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Humanity has got its earliest ever look at the dawn of the universe as a dazzling, unprecedented batch of images are revealed to the world for the first time.Billed as the 'next giant leap in space astronomy', they were taken by the new James Webb Space Telescope — a successor to the famous Hubble observatory — and are being released by NASA at a global press conference today.It puts an end to months of waiting and feverish anticipation as people across the globe are treated to a view that is actually more than 13 billion years in the making.Webb's infrared capabilities mean it can 'see back in time' to within a mere 100-200 million years of the Big Bang, allowing it to take pictures of the very first stars to shine in the universe.Its first images are of nebulae, an exoplanet and galaxy clusters, on what has been hailed a 'great day for humanity'.One spectacular picture captures a planetary nebula caused by a dying star — a fate that awaits our sun some time in the distant future.Nearly half a light-year in diameter and located approximately 2,500 light-years away from Earth, the Southern Ring Nebula can be seen in incredible never-before-seen detail.Among the other images revealed is an analysis of the atmosphere of a giant planet outside our solar system called WASP-96 b — located nearly 1,150 light-years from Earth.It is the first ever spectrum analysis of an exoplanet's atmosphere.Webb captured the distinct signature of water, along with evidence for clouds and haze, in the atmosphere surrounding the hot, puffy gas giant planet, which orbits a distant sun-like star every 3.4 days. WASP-96 b has about half the mass of Jupiter, and its discovery was announced in 2014.While the Hubble Space Telescope has analysed numerous exoplanet atmospheres over the past two decades, capturing the first clear detection of water in 2013, NASA said that Webb's immediate and more detailed observation marks a giant leap forward in the quest to characterize potentially habitable planets beyond Earth.Scroll down for video Humanity has got its earliest ever look at the dawn of the universe as a dazzling, unprecedented batch of images are revealed to the world for the first time. One spectacular picture captures a planetary nebula caused by a dying star — a fate that awaits our sun some time in the distant future Two cameras aboard Webb captured the latest image of this planetary nebula, cataloged as NGC 3132, and known informally as the Southern Ring Nebula. It is approximately 2,500 light-years away Webb also analysed the atmosphere of a giant planet outside our solar system called WASP-96 b (pictured) — a giant gas located nearly 1,150 light-years from Earth which orbits its star every 3.4 days Spectacular: Pictured is the first image from the James Webb Space Telescope, showing SMACS 0723, a galaxy cluster billions of light-years from Earth. It was revealed to the world yesterday by US President Joe Biden HOW DOES JAMES WEBB SEE BACK IN TIME? The further away an object is, the further back in time we are looking. This is because of the time it takes light to travel from the object to us.With James Webb's larger mirror, it will be able to see almost the whole way back to the beginning of the universe, more than 13.5 billion years ago.With its ability to view the Universe in longer wavelength infrared light, James Webb will be capable of seeing some of the most distant galaxies in our universe, certainly with more ease than than the visible/ultraviolet light view of Hubble.This is because light from distant objects is stretched out by the expansion of our universe - an effect known as redshift - pushing the light out of the visible range and into infrared.Source: Royal Museums Greenwich Yesterday, US President Joe Biden previewed the main event as he unveiled one of Webb's images that showed a cluster of galaxies 4 billion light-years away from Earth.This provided the deepest and sharpest infrared look at the distant universe to date, capturing the galaxy cluster SMACS 0723 as it appeared 4.6 billion years ago.President Biden called it 'a historic moment for science and technology, for astronomy and space exploration and all of humanity'.This deep field, taken by Webb's Near-Infrared Camera (NIRCam), is a composite made from images at different wavelengths and took just 12.5 hours to compile, compared with the weeks it took predecessor Hubble to observe other 'deep fields' – images of a portion of the sky taken with a very long exposure time.According to NASA, SMACS 0723 has a gravitational pull so powerful that it warps both space-time and the path that light subsequently travels through it.By studying this light, scientists want to learn about the origins of the cosmos, and possibly even catch a glimpse of the elusive photons that came from the very first stars to ever exist. NASA said Webb's NIRCam has brought distant galaxies into sharp focus in the new image — they have tiny, faint structures that have never been seen before, including star clusters and diffuse features. 'If you held a grain of sand on the tip of your finger at arm's length. That's what you're seeing, just one little speck, said NASA administrator Bill Nelson. 'You're seeing galaxies that are shining around other galaxies who's light has been bent and you're seeing just a small little portion of the universe.'We're looking back more than 13 billion years. Light travels at 186,000 miles per second — that light that you're seeing on one of those little specks has been traveling for 13 billion years.'By the way, we're going further.'Since we know the universe is 13.8 billion years old, we're going back almost to the beginning.' Nelson said the $10 billion (£7.4 billion) observatory is so precise that scientists will be able to see whether or not planets in other galaxies are habitable — so whether or not they can host life, possibly like on Earth. The telescope (pictured), which was launched from Guiana Space Centre in French Guiana on December 25 last year, will explore the universe in the infrared spectrum, allowing it to gaze through clouds of gas and dust where stars are being bornWebb's infrared capabilities allow it to 'see back in time' to the Big Bang, which happened 13.8 billion years ago. Light waves move extremely fast, about 186,000 miles (300,000 km) per second, every second. The further away an object is, the further back in time we are looking. This is because of the time it takes light to travel from the object to us WHAT IS THE DIFFERENCE BETWEEN WEBB AND HUBBLE? NASA likes to think of James Webb as a successor to Hubble rather than a replacement, as the two will work in tandem for a while.That's because they look at stars and galaxies in different ways. Hubble studies the universe predominantly at optical, or visible, wavelengths, which is the same type of light we detect with our eyes.Webb, on the other hand, is set up to specifically look in the infrared, which is invisible to our eyes but allows it to identify the glow from the most distant objects in the universe.It works in much the same way night vision goggles use thermal imaging technology to capture infrared light. Researchers will soon begin to learn more about the galaxies' masses, ages, histories and compositions, as Webb seeks the earliest galaxies in the universe. The telescope, which was launched from Guiana Space Centre in French Guiana on December 25 last year, will explore the universe in the infrared spectrum, allowing it to gaze through clouds of gas and dust where stars are being born.In comparison, its predecessor Hubble has operated primarily at optical and ultraviolet wavelengths since its launch in 1990.As the universe is expanding, light from the earliest stars shifts from the ultraviolet and visible wavelengths it was emitted in, to longer infrared wavelengths.Astronomers will use Webb to observe the infrared universe, analyse the data collected, and publish scientific papers on their discoveries.'James Webb allows us to see deeper into space than ever before,' said Vice President Kamala Harris, who leads the National Space Council.'It will enhance what we know about our universe our solar system and possibly life itself.'Webb is the most advanced telescope ever built and is 100 times more powerful than the Hubble Space Telescope, which is still operational 32 years after its launch.Last week, NASA shared its list of targets for the first images to be captured by Webb — including the giant exoplanet WASP-96 b, the Carina Nebula and Stephan's Quintet. Yesterday, US President Joe Biden previewed the main event as he unveiled one of Webb's images that showed a cluster of galaxies 4 billion light-years away from Earth Webb's primary mirror consists of 18 hexagonal segments of gold-plated beryllium metal, and measures 21 feet 4 inches (6.5 metres) in diameter. It is supported by three shallow carbon fibre tubes, or struts, that extend out from the primary mirror TARGETS ACQUIRED! WHAT JAMES WEBB HAS CAPTURED FIRST The targets of the James Webb Space Telescope's first images were: SMACS 0723Massive foreground galaxy clusters magnify and distort the light of objects behind them, permitting a deep field view into both the extremely distant and intrinsically faint galaxy populations. Carina NebulaThe Carina Nebula is one of the largest and brightest nebulae in the sky, located approximately 7,600 light-years away in the southern constellation Carina. Nebulae are stellar nurseries where stars form. The Carina Nebula is home to many massive stars, several times larger than the sun.WASP-96bWASP-96 b is a giant planet outside our solar system, composed mainly of gas. The planet, located nearly 1,150 light-years from Earth, orbits its star every 3.4 days. It has about half the mass of Jupiter, and its discovery was announced in 2014. Southern Ring NebulaThe Southern Ring, or 'Eight-Burst' nebula, is a planetary nebula – an expanding cloud of gas, surrounding a dying star. It is nearly half a light-year in diameter and is located approximately 2,000 light years away from Earth. Stephan's QuintetAbout 290 million light-years away, Stephan's Quintet is located in the constellation Pegasus. It is notable for being the first compact galaxy group ever discovered in 1877. Four of the five galaxies within the quintet are locked in a cosmic dance of repeated close encounters. WASP-96 b, which was discovered in 2014, is a giant planet outside of our solar system that is composed mainly of gas.It is 1,150 light-years from Earth, orbits its star every 3.4 days is about half the mass of Jupiter.Stephan's Quintet is located in the constellation Pegasus and is known for being the first compact galaxy group ever discovered in 1787.Four of the five galaxies within the quintet are locked in a cosmic dance of repeated close encounters, NASA said.Webb has an ambitious mission to study the early universe, work out how fast it is now expanding and analyse objects throughout the cosmos ranging from galaxies to exoplanets.The telescope has a gigantic golden mirror measuring just over 21 feet across that is made up of 18 individual hexagonal segments that can fold up and unfold.They were slowly and meticulously deployed over the past six months to prepare James Webb for its science mission.The observatory and most of its instruments have an operating temperature of roughly 40 Kelvin – about minus 387 Fahrenheit (minus 233 Celsius). Anticipation for the images has only grown as NASA scientists have shared their thoughts over the last week. 'What I have seen moved me, as a scientist, as an, and as a human being,' NASA's deputy administrator, Pam Melroy, said in a press conference in June. NASA administrator Bill Nelson said earlier this month that Webb would be able to gaze further into space than any telescope before it.'It's going to explore objects in the solar system and atmospheres of exoplanets orbiting other stars, giving us clues as to whether potentially their atmospheres are similar to our own,' he said.'It may answer some questions that we have: Where do we come from? What more is out there? Who are we? 'And of course, it's going to answer some questions that we don't even know what the questions are.' Beyond what is already planned for Webb, there are the unexpected discoveries astronomers cannot anticipate. In 1990, when Hubble was launched, dark energy was completely unknown. Now it is one of the most exciting areas of astrophysics. Last week NASA shared a 'teaser' image ahead of the eagerly-anticipated release of the first deep-space pictures from its James Webb Space Telescope Webb is pictured prior to launch. The primary mirror is composed of 18 hexagonal segments made of the metal beryllium and coated with gold to capture faint infrared light INSTRUMENTS ON THE JAMES WEBB TELESCOPE NIRCam (Near InfraRed Camera) an infrared imager from the edge of the visible through the near infrared NIRSpec (Near InfraRed Spectrograph) will also perform spectroscopy over the same wavelength range. MIRI (Mid-InfraRed Instrument) will measure the mid-to-long-infrared wavelength range from 5 to 27 micrometers.FGS/NIRISS (Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph), is used to stabilise the line-of-sight of the observatory during science observations. NASA likes to think of James Webb as a successor to Hubble rather than a replacement, as the two will work in tandem for a while.That's because they look at stars and galaxies in different ways. Hubble studies the universe predominantly at optical, or visible, wavelengths, which is the same type of light we detect with our eyes.Webb, on the other hand, is set up specifically to look in the infrared, which is invisible to our eyes but allows it to identify the glow from the most distant objects in the universe.It works in much the same way night vision goggles use thermal imaging technology to capture infrared light.Currently, the earliest cosmological observations date to within 330 million years of the Big Bang, but with Webb's capacities, astronomers believe they will easily break the record.The telescope and most of its instruments have an operating temperature of roughly 40 Kelvin – about minus 387 Fahrenheit (minus 233 Celsius). It began development in 1996 and was originally envisaged to launch in 2007, but a major redesign in 2005 put this back and a series of further delays led to it eventually making it to orbit at the end of last year.THE JAMES WEBB TELESCOPE The James Webb telescope has been described as a 'time machine' that could help unravel the secrets of our universe.The telescope will be used to look back to the first galaxies born in the early universe more than 13.5 billion years ago, and observe the sources of stars, exoplanets, and even the moons and planets of our solar system.The vast telescope, which has already cost more than $7 billion (£5 billion), is considered a successor to the orbiting Hubble Space TelescopeThe James Webb Telescope and most of its instruments have an operating temperature of roughly 40 Kelvin – about minus 387 Fahrenheit (minus 233 Celsius).It is the world's biggest and most powerful orbital space telescope, capable of peering back 100-200 million years after the Big Bang.The orbiting infrared observatory is designed to be about 100 times more powerful than its predecessor, the Hubble Space Telescope.NASA likes to think of James Webb as a successor to Hubble rather than a replacement, as the two will work in tandem for a while. The Hubble telescope was launched on April 24, 1990, via the space shuttle Discovery from Kennedy Space Centre in Florida.It circles the Earth at a speed of about 17,000mph (27,300kph) in low Earth orbit at about 340 miles in altitude.
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Cosmology & The Universe
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Astronomers discover new link between dark matter and clumpiness of the universe
In a study published today in the Journal of Cosmology and Astroparticle Physics, researchers at the University of Toronto reveal a theoretical breakthrough that may explain both the nature of invisible dark matter and the large-scale structure of the universe known as the cosmic web. The result establishes a new link between these two longstanding problems in astronomy, opening new possibilities for understanding the cosmos.
The research suggests that the "clumpiness problem," which centers on the unexpectedly even distribution of matter on large scales throughout the cosmos, may be a sign that dark matter is composed of hypothetical, ultra-light particles called axions. The implications of proving the existence of hard-to-detect axions extend beyond understanding dark matter and could address fundamental questions about the nature of the universe itself.
"If confirmed with future telescope observations and lab experiments, finding axion dark matter would be one of the most significant discoveries of this century," says lead author Keir Rogers, Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics in the Faculty of Arts & Science at the University of Toronto.
"At the same time, our results suggest an explanation for why the universe is less clumpy than we thought, an observation that has become increasingly clear over the last decade or so, and currently leaves our theory of the universe uncertain."
Dark matter, comprising 85 percent of the universe's mass, is invisible because it does not interact with light. Scientists study its gravitational effects on visible matter to understand how it is distributed in the universe.
A leading theory proposes that dark matter is made of axions, described in quantum mechanics as "fuzzy" due to their wave-like behavior. Unlike discrete point-like particles, axions can have wavelengths larger than entire galaxies. This fuzziness influences the formation and distribution of dark matter, potentially explaining why the universe is less clumpy than predicted in a universe without axions.
This lack of clumpiness has been observed in large galaxy surveys, challenging the other prevailing theory that dark matter consists only of heavy, weakly interacting sub-atomic particles called WIMPs. Despite experiments like the Large Hadron Collider, no evidence supporting the existence of WIMPs has been found.
"In science, it's when ideas break down that new discoveries are made and age-old problems are solved," says Rogers.
For the study, the research team—led by Rogers and including members of associate professor Renée Hložek's research group at the Dunlap Institute, as well as from the University of Pennsylvania, Institute for Advanced Study, Columbia University and King's College London—analyzed observations of relic light from the Big Bang, known as the Cosmic Microwave Background (CMB), obtained from the Planck 2018, Atacama Cosmology Telescope and South Pole Telescope surveys.
The researchers compared these CMB data with galaxy clustering data from the Baryon Oscillation Spectroscopic Survey (BOSS), which maps the positions of approximately a million galaxies in the nearby universe. By studying the distribution of galaxies, which mirrors the behavior of dark matter under gravitational forces, they measured fluctuations in the amount of matter throughout the universe and confirmed its reduced clumpiness compared to predictions.
The researchers then conducted computer simulations to predict the appearance of relic light and the distribution of galaxies in a universe with long dark matter waves. These calculations aligned with CMB data from the Big Bang and galaxy clustering data, supporting the notion that fuzzy axions could account for the clumpiness problem.
Future research will involve large-scale surveys to map millions of galaxies and provide precise measurements of clumpiness, including observations over the next decade with the Rubin Observatory.
The researchers hope to compare their theory to direct observations of dark matter through gravitational lensing, an effect where dark matter clumpiness is measured by how much it bends the light from distant galaxies, akin to a giant magnifying glass. They also plan to investigate how galaxies expel gas into space and how this affects the dark matter distribution to further confirm their results.
Understanding the nature of dark matter is one of the most pressing fundamental questions and key to understanding the origin and future of the universe.
Presently, scientists do not have a single theory that simultaneously explains gravity and quantum mechanics—a theory of everything. The most popular theory of everything over the last few decades is string theory, which posits another level below the quantum level, where everything is made of string-like excitations of energy. According to Rogers, detecting a fuzzy axion particle could be a hint that the string theory of everything is correct.
"We have the tools now that could enable us to finally understand something experimentally about the century-old mystery of dark matter, even in the next decade or so—and that could give us hints to answers about even bigger theoretical questions," says Rogers. "The hope is that the puzzling elements of the universe are solvable."
More information: Ultra-light axions and the S8 tension: joint constraints from the cosmic microwave background and galaxy clustering, Journal of Cosmology and Astroparticle Physics (2023). DOI: 10.1088/1475-7516. iopscience.iop.org/article/10. … 475-7516/2023/06/023
Provided by University of Toronto
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Cosmology & The Universe
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Astronomers have detected a hot bubble of gas swirling around the Milky Way's supermassive black hole at over 200 million miles an hour.It is circling Sagittarius A* at almost a third of the speed of light on an orbit similar in size to that of the planet Mercury, completing a full circle in just 70 minutes.Experts say the discovery could help us to better understand the enigmatic and dynamic environment of the enormous void at the heart of our galaxy.Lead author Dr Maciek Wielgus, of the Max Planck Institute for Radio Astronomy in Germany, said: 'We think we're looking at a hot bubble of gas zipping around Sagittarius A* on an orbit similar in size to that of the planet Mercury — but making a full loop in just around 70 minutes.'He added: 'This requires a mind-blowing velocity of about 30 per cent of the speed of light.' Mysterious: Astronomers have detected a hot bubble of gas swirling around the Milky Way's supermassive black hole at over 200 million miles an hour. The ALMA radio telescope spotted signs of a 'hot spot' orbiting Sagittarius A* (shown), the black hole at the centre of our galaxy WHAT IS SAGITTARIUS A* AND HOW WAS IT CAUGHT ON CAMERA? Sagittarius A* - abbreviated to Sgr A*, which is pronounced "sadge-ay-star" - owes its name to its detection in the direction of the constellation Sagittarius.Its existence has been assumed since 1974, with the detection of an unusual radio source at the centre of the galaxy.In the 1990s, astronomers mapped the orbits of the brightest stars near the centre of the Milky Way, confirming the presence of a supermassive compact object there - work that led to the 2020 Nobel Prize in Physics.Though the presence of a black hole was thought to be the only plausible explanation, the new image provides the first direct visual proof.Because it is 27,000 light years from Earth, it appears the same size in the sky as a donut on the moon.Capturing images of such a faraway object required linking eight giant radio observatories across the planet to form a single 'Earth-sized' virtual telescope called the EHT.These included the Institute for Millimeter Radio Astronomy (IRAM) 30-meter telescope in Spain, the most sensitive single antenna in the EHT network.The EHT gazed at Sgr A* across multiple nights for many hours in a row - a similar idea to long-exposure photography and the same process used to produce the first image of a black hole, released in 2019.That black hole is called M87* because it is in the Messier 87 galaxy. An international team spotted the 'hot spot' using the ALMA (Atacama Large Millimeter/submillimeter Array) radio telescope in the Chilean Andes. Supermassive black holes are incredibly dense areas in the centre of galaxies. They act as intense sources of gravity which hoover up dust and gas around them. Sagittarius A* – located just 26,000 light years from Earth – is one of very few black holes in the universe where we can actually witness the flow of matter nearby.But as the area absorbs all surrounding light, it is incredibly difficult to see, so scientists have spent decades searching for hints of black hole activity.The observations were made by the European Southern Observatory (ESO) during a campaign by the Event Horizon Telescope (EHT) Collaboration to image black holes.In April 2017 eight existing radio telescopes were linked worldwide, resulting in the first ever image of Sagittarius A*.Dr Wielgus and colleagues used ALMA data recorded simultaneously with the EHT observations of Sagittarius A*.There were more clues to the nature of the black hole hidden in the ALMA-only measurements.Serendipitously, some were done shortly after a burst or flare of X-ray energy was emitted from the centre of the Milky Way and detected by NASA's Chandra Space Telescope.These kinds of flares, previously observed with X-ray and infrared telescopes, are thought to be associated with 'hot spots' — gas bubbles that orbit very fast and close to the black hole.Dr Wielgus said: 'What is really new and interesting is such flares were so far only clearly present in X-ray and infrared observations of Sagittarius A*.'Here we see for the first time a very strong indication that orbiting hot spots are also present in radio observations.'Less than one per cent of the material initially within the black hole's gravitational influence reaches the event horizon, or point of no return, because much of it is ejected.Consequently, the X-ray emission from material is remarkably faint, like that of most of the giant black holes in galaxies in the nearby universe.Co author Jesse Vos, a PhD student at Radboud University, the Netherlands, said: 'Perhaps these hot spots detected at infrared wavelengths are a manifestation of the same physical phenomenon.'As infrared-emitting hot spots cool down, they become visible at longer wavelengths, like the ones observed by ALMA and the EHT.'The flares were thought to originate from magnetic interactions in the extremely hot gas orbiting very close to the black hole. The research's findings support this idea.Co-author Dr Monika Moscibrodzka, also from Radboud, said: 'Now we find strong evidence for a magnetic origin of these flares and our observations give us a clue about the geometry of the process.'The new data are extremely helpful for building a theoretical interpretation of these events.'ALMA allows astronomers to study polarised radio emission from Sagittarius A*, which can be used to unveil the black hole's magnetic field. An international team spotted the 'hot spot' using the ALMA (Atacama Large Millimeter/submillimeter Array) radio telescope in the Chilean Andes (pictured)The data combined with theoretical models shed light on the formation of the hot spot and the environment it is embedded in, including the magnetic field.Stronger constraints on the shape of than previous observations help uncover the nature of our black hole and its surroundings.Scans by ALMA and the GRAVITY instrument at ESO's Very Large Telescope (VLT), which observes in the infrared, suggest the flare originates in a clump of gas.It swirls around the black hole at about 30 percent of the speed of light in a clockwise direction in the sky — with the orbit of the hot spot being nearly face-on.Co author Dr Ivan Marti-Vidal, of the University of Valencia, said: 'In future we should be able to track hot spots across frequencies using coordinated multiwavelength observations with both GRAVITY and ALMA.'The success of such an endeavour would be a true milestone for our understanding of the physics of flares in the Galactic centre.' This visible light wide-field view shows the rich star clouds in the constellation of Sagittarius (the Archer) in the direction of the centre of our Milky Way galaxyThe team is also hoping to be able to directly observe the orbiting gas clumps with the EHT, to probe ever closer to the black hole and learn more about it. Dr Wielgus added: 'Hopefully, one day, we will be comfortable saying we "know" what is going on in Sagittarius A*.'How black holes form is still poorly understood. Astronomers believe it happens when a large cloud of gas up to 100,000 times bigger than the sun collapses.Many of these 'seeds' then merge to form much larger supermassive black holes, which are found at the centre of every known massive galaxy.Alternatively, a supermassive black hole seed could come from a giant star, about 100 times the sun's mass, that ultimately forms into a black hole after it runs out of fuel and collapses.When these giant stars die, they also go 'supernova', a huge explosion that expels the matter from the outer layers of the star into deep space.The new study has been published in the journal Astronomy & Astrophysics. WHAT IS ALMA?Deep in the Chilean desert, the Atacama Large Millimetre Array, or ALMA, is located in one of the driest places on Earth.At an altitude of 16,400ft, roughly half the cruising height of a jumbo jet and almost four times the height of Ben Nevis, workers had to carry oxygen tanks to complete its construction.Switched on in March 2013, it is the world's most powerful ground based telescope.It is also the highest on the planet and, at almost £1 billion ($1.2 billion), one of the most expensive of its kind. Deep in the Chilean desert, the Atacama Large Millimetre Array, or ALMA, is located in one of the driest places on Earth. Switched on in March 2013, it is the world's most powerful ground based telescope
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Cosmology & The Universe
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It’s got a mirror that looks like a honeycomb and can peer deep into the universe. Here’s what to know about NASA’s James Webb Space Telescope, and what its colorful images could tell us about what’s beyond the Milky Way.1. NASA launched the telescope from a space center in South America last December.The telescope took off on Christmas morning from the Guiana Space Center in French Guiana, attached to another rocket. In January, it reached a point in space one million miles from earth and began to prep for picture-taking.On Monday, July 11, President Joe Biden revealed the first full-color image from the James Webb Space Telescope at a White House event. NASA released several more images during a live TV broadcast on July 12.Related:First image of universe from James Webb Telescope shared by NASA, White House2. It’s the most powerful telescope ever sent into space.The James Webb Space Telescope isn’t the only telescope on the block. NASA’s Hubble Space Telescope has been orbiting the earth since 1990.But James Webb can take pictures at a much higher resolution than Hubble, presenting scientists with sharper, clearer images of galaxies millions of light years away.“We’re getting quality and resolution like we haven’t seen before,” said McKenna Dowd, a program coordinator at the University of Texas at Arlington’s Planetarium.Dowd said telescopes like the James Webb collect light for their images similar to how water collects in a rain bucket. The bigger the bucket, the more light that can be collected and reflected back to the telescope’s camera.The James Webb Space Telescope’s primary mirror, which looks a bit like a honeycomb, is the telescope’s “bucket.” It’s the biggest mirror NASA has sent into space, meaning it can collect even more light and information.FILE - This March 5, 2020, photo made available by NASA shows the main mirror assembly of the James Webb Space Telescope during testing at a Northrop Grumman facility in Redondo Beach, Calif. (Chris Gunn/NASA via AP, File)(Chris Gunn / ASSOCIATED PRESS)3. It can see past “space dust.”Nevin Weinberg, an associate professor of physics at UT Arlington, said many of the Hubble Telescope’s images feature clouds of space dust: tiny particles that float around between stars. The dust can absorb certain wavelengths of light, preventing scientists from seeing what’s through the clouds.With the James Webb Space Telescope, that’s about to change.According to Weinberg, the space telescope can take pictures in a wavelength of light called infrared, which is different from the wavelengths of light that we can see. Space dust can’t absorb infrared light as easily, meaning that some of the light can pass through the clouds.“That is a way of seeing through the dust,” Weinberg said, “into the heart of whatever you’re trying to look at.”That heart could be anything from the core of a galaxy to a young star, Weinberg said.Related:See the latest images as NASA’s new telescope shows a dying star, dancing galaxies4. The telescope can see back in time.The universe is constantly getting bigger, which means things are constantly moving closer and further away from us. The further away something is, the longer it takes for its light to reach us. By the time scientists can get a picture of a galaxy billions of light years away, a fair amount of time has passed since that galaxy got its photo snapped.That means photos of the universe are like windows into the past.“When we see a galaxy that’s a billion light years away, we’re seeing it as it was a billion years ago,” Weinberg said.The first image released from the James Webb Space Telescope contains glamour shots of galaxies from as long ago as 4.6 billion years ago, with the oldest being from 13.1 billion years ago. Weinberg said some of the redder dots and smears in the image are galaxies way out into the universe: both in space and in time.5. Scientists hope its pictures can tell us how our universe came to be.Dowd says scientists can use the telescope’s images to investigate how stars live and die, and even how planets form. They can also study the telescope’s time-traveling images of early galaxies to figure out how those galaxies came to be.Dowd says determining the answer to that question could help us understand how the galaxy we live in, the Milky Way, came about, too.The telescope has the potential to answer scientists’ burning questions about the origin story of the universe – a universe that we’re very much a part of.This image released by NASA on Tuesday, July 12, 2022, shows the edge of a nearby, young, star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) on the James Webb Space Telescope, this image reveals previously obscured areas of star birth, according to NASA. (NASA, ESA, CSA, and STScI via AP)(Uncredited / ASSOCIATED PRESS)Adithi Ramakrishnan is a science reporting fellow at The Dallas Morning News. Her fellowship is supported by the University of Texas at Dallas. The News makes all editorial decisions.Adithi Ramakrishnan, Science reporting fellow. Adithi recently graduated from the College of William and Mary with a degree in neuroscience and has previously written for WUNC - North Carolina Public Radio, the National Association of Science Writers, and Massive Science. adithi.ramakrishnan@dallasnews.com adithi_r1
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Cosmology & The Universe
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The scientists say they have observed a new kind of “pentaquark” and the first-ever pair of “tetraquarks,” adding three members to the list of new hadrons found at the LHC.A worker walks in the CERN's Large Hadron Collider (LHC) tunnel during maintenance works on July 19, 2013 in Meyrin, near Geneva.Fabrice Coffrini / AFP via Getty Images fileJuly 5, 2022, 3:45 PM UTCScientists working with the Large Hadron Collider (LHC) have discovered three subatomic particles never seen before as they work to unlock the building blocks of the universe, the European nuclear research centre CERN said on Tuesday.The 27 kilometre-long (16.8 mile) LHC at CERN is the machine that found the Higgs boson particle, which along with its linked energy field is thought to be vital to the formation of the universe after the Big Bang 13.7 billion years ago.Now scientists at CERN say they have observed a new kind of “pentaquark” and the first-ever pair of “tetraquarks,” adding three members to the list of new hadrons found at the LHC.They will help physicists better understand how quarks bind together into composite particles.Quarks are elementary particles that usually combine in groups of twos and threes to form hadrons such as the protons and neutrons that make up atomic nuclei.More rarely, however, they can also combine into four-quark and five-quark particles, or tetraquarks and pentaquarks.“The more analyses we perform, the more kinds of exotic hadrons we find,” physicist Niels Tuning said in a statement.“We’re witnessing a period of discovery similar to the 1950s, when a ‘particle zoo’ of hadrons started being discovered and ultimately led to the quark model of conventional hadrons in the 1960s. We’re creating ‘particle zoo 2.0’.”
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Cosmology & The Universe
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NASA is scheduled to release some of the very first images taken by the James Webb Space Telescope on July 12, 2022. They’ll mark the beginning of the next era in astronomy as Webb – the largest space telescope ever built – offers scientific data that will help answer questions about the earliest moments of the universe and allow astronomers to study exoplanets in greater detail than ever before.
NASA is expected to reveal the new images beginning at 10:30 a.m. EDT. Watch live in our player above.
But it has taken nearly eight months of travel, setup, testing and calibration to make sure this most valuable of telescopes is ready for prime time. Marcia Rieke, an astronomer at the University of Arizona and the scientist in charge of one of Webb’s four cameras, explains what she and her colleagues have been doing to get this telescope up and running.
READ MORE: Here’s the deepest, clearest infrared image of the universe ever produced
What’s happened since the telescope launched?
After the successful launch of the James Webb Space Telescope on Dec. 25, 2021, the team began the long process of moving the telescope into its final orbital position, unfolding the telescope and – as everything cooled – calibrating the cameras and sensors onboard.
The launch went as smoothly as a rocket launch can go. One of the first things my colleagues at NASA noticed was that the telescope had more remaining fuel onboard than predicted to make future adjustments to its orbit. This will allow Webb to operate for much longer than the mission’s initial 10-year goal.
The first task during Webb’s monthlong journey to its final location in orbit was to unfold the telescope. This went along without any hitches, starting with the white-knuckle deployment of the sun shield that helps cool the telescope, followed by the alignment of the mirrors and the turning on of sensors.
WATCH: Biden offers first peek of historic image from James Webb Space Telescope
Once the sun shield was open, our team began monitoring the temperatures of the four cameras and spectrometers onboard, waiting for them to reach temperatures low enough so that we could start testing each of the 17 different modes in which the instruments can operate. The NIRCam on Webb was the first instrument to go online and helped align the 18 mirror segments. NASA Goddard Space Center/Wikimedia Commons
What did you test first?
The cameras on Webb cooled just as the engineers predicted, and the first instrument the team turned on was the Near Infrared Camera – or NIRCam. NIRCam is designed to study the faint infrared light produced by the oldest stars or galaxies in the universe. But before it could do that, NIRCam had to help align the 18 individual segments of Webb’s mirror.
Once NIRCam cooled to minus 280 F, it was cold enough to start detecting light reflecting off of Webb’s mirror segments and produce the telescope’s first images. The NIRCam team was ecstatic when the first light image arrived. We were in business!
These images showed that the mirror segments were all pointing at a relatively small area of the sky, and the alignment was much better than the worst-case scenarios we had planned for.
Webb’s Fine Guidance Sensor also went into operation at this time. This sensor helps keep the telescope pointing steadily at a target – much like image stabilization in consumer digital cameras. Using the star HD84800 as a reference point, my colleagues on the NIRCam team helped dial in the alignment of the mirror segments until it was virtually perfect, far better than the minimum required for a successful mission.
What sensors came alive next?
As the mirror alignment wrapped up on March 11, the Near Infrared Spectrograph – NIRSpec – and the Near Infrared Imager and Slitless Spectrograph – NIRISS – finished cooling and joined the party.
NIRSpec is designed to measure the strength of different wavelengths of light coming from a target. This information can reveal the composition and temperature of distant stars and galaxies. NIRSpec does this by looking at its target object through a slit that keeps other light out.
WATCH: NASA’s James Webb telescope poised to launch new golden age of astronomy
NIRSpec has multiple slits that allow it to look at 100 objects at once. Team members began by testing the multiple targets mode, commanding the slits to open and close, and they confirmed that the slits were responding correctly to commands. Future steps will measure exactly where the slits are pointing and check that multiple targets can be observed simultaneously.
NIRISS is a slitless spectrograph that will also break light into its different wavelengths, but it is better at observing all the objects in a field, not just ones on slits. It has several modes, including two that are designed specifically for studying exoplanets particularly close to their parent stars.
So far, the instrument checks and calibrations have been proceeding smoothly, and the results show that both NIRSpec and NIRISS will deliver even better data than engineers predicted before launch. The MIRI camera, image on the right, allows astronomers to see through dust clouds with incredible sharpness compared with previous telescopes like the the Spitzer Space Telescope, which produced the image on the left. NASA/JPL-Caltech (left), NASA/ESA/CSA/STScI (right)/Flickr, CC BY
What was the last instrument to turn on?
The final instrument to boot up on Webb was the Mid-Infrared Instrument, or MIRI. MIRI is designed to take photos of distant or newly formed galaxies as well as faint, small objects like asteroids. This sensor detects the longest wavelengths of Webb’s instruments and must be kept at minus 449 F – just 11 degrees F above absolute zero. If it were any warmer, the detectors would pick up only the heat from the instrument itself, not the interesting objects out in space. MIRI has its own cooling system, which needed extra time to become fully operational before the instrument could be turned on.
Radio astronomers have found hints that there are galaxies completely hidden by dust and undetectable by telescopes like Hubble that captures wavelengths of light similar to those visible to the human eye. The extremely cold temperatures allow MIRI to be incredibly sensitive to light in the mid-infrared range which can pass through dust more easily. When this sensitivity is combined with Webb’s large mirror, it allows MIRI to penetrate these dust clouds and reveal the stars and structures in such galaxies for the first time.
What’s next for Webb?
As of June 15, 2022, all of Webb’s instruments are on and have taken their first images. Additionally, four imaging modes, three time series modes and three spectroscopic modes have been tested and certified, leaving just three to go.
On July 12, NASA plans to release a suite of teaser observations that illustrate Webb’s capabilities. These will show the beauty of Webb imagery and also give astronomers a real taste of the quality of data they will receive.
After July 12, the James Webb Space Telescope will start working full time on its science mission. The detailed schedule for the coming year hasn’t yet been released, but astronomers across the world are eagerly waiting to get the first data back from the most powerful space telescope ever built.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Cosmology & The Universe
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By Matt WilliamsThe idea of one day traveling to another star system and seeing what is there has been the fevered dream of people long before the first rockets and astronauts were sent to space. But despite all the progress we have made since the beginning of the Space Age, interstellar travel remains just that – a fevered dream. While theoretical concepts have been proposed, the issues of cost, travel time and fuel remain highly problematic.A lot of hopes currently hinge on the use of directed energy and lightsails to push tiny spacecrafts to relativistic speeds. But what if there was a way to make larger spacecraft fast enough to conduct interstellar voyages? According to Prof. David Kipping – the leader of Columbia University’s Cool Worlds lab – future spacecraft could rely on a Halo Drive, which uses the gravitational force of a black hole to reach incredible speeds. Prof. Kipping described this concept in a recent study that appeared online (the preprint is also available on the Cool Worlds website). In it, Kipping addressed the single-greatest challenges posed by space exploration, which is the sheer amount of time and energy it would take to send a spacecraft on a mission to explore beyond our Solar System.As Kipping told Universe Today via email:“Interstellar travel is one of the most challenging technical feats we can conceive of. Whilst we can envisage drifting between the stars over millions of years – which is legitimately interstellar travel – to achieve journeys on timescales of centuries or less requires relativistic propulsion.” As Kipping put it, relativistic propulsion (or accelerating to a fraction of the speed of light) is very expensive in terms of energy. Existing spacecraft simply don’t have the fuel capacity in order to be able to get up to those kinds of speeds, and short of detonating nukes to generate thrust – à la Project Orion (video above) – or building a fusion ramjet – à la Project Daedalus – there are not a lot of options available.In recent years, attention has shifted towards the idea of using lightsails and nanocraft to conduct interstellar missions. A well-known example of this is Breakthrough Starshot, an initiative that aims to send a smartphone-sized spacecraft to Alpha Centauri within our lifetime. Using a powerful laser array, the lightsail would be accelerated to speeds of up to 20% of the speed of light – thus making the trip in 20 years.“But even here you are talking about several terra-joules of energy for the most minimalist (a gram-mass) spacecraft conceivable,” said Kipping. “That’s the cumulative energy output of nuclear power stations running for weeks on end (which by the way we have no way of storing so much energy either)! So this is why it’s hard.” To this, Kipping suggests a modified version of what is known as the “Dyson Slingshot“, an idea was proposed by venerated theoretical physicist Freeman Dyson (the mind behind the Dyson Sphere). In the 1963 book, Interstellar Communications (Chapter 12: “Gravitational Machines“), Dyson described how spacecraft could slingshot around compact binary stars in order to receive a significant boost in velocity.As Dyson described it, a ship that would be dispatched to a compact binary system (two neutron stars that orbit each other) where it would perform a gravity-assist maneuver. This would consist of the spaceship picking up speed from the binary’s intense gravity – adding the equivalent of twice their rotational velocity to its own – before being flung out of the system.While the prospect of harnessing this kind of energy for the sake of propulsion was highly theoretical in Dyson’s time (and still is), Dyson offered two reasons why “gravitational machines” were worth exploring:“First, if our species continues to expand its population and its technology at an exponential rate, there may come a time in the remote future where engineering on an astronomical scale may be both feasible and necessary. Second, if we are searching for signs of technologically advanced life already existing elsewhere in the universe, it is useful to consider what kind of observable phenomena a really advanced technology might be capable of producing.” In short, gravitational machines are worth studying in case they become possible someday, and because this study could allow us to spot possible extra-terrestrial intelligences (ETIs) through the technosignatures such machines would create. Expanding upon this, Kipping considers how black holes – especially those found in binary pairs – could constitute even more powerful gravitational slingshots.This proposal is based in part on the recent success of the Laser Interferometer Gravitational-Wave Observatory (LIGO), which has picked multiple gravitational waves signals since the first was detected in 2016. According to recent estimates based on these detections, there could be as many as 100 million black holes in the Milky Way galaxy alone.Where binaries occur, they possess an incredible amount of rotational energy, which is the result of their spin and the way they rapidly orbit one another. In addition, as Kipping notes, black holes can also act as a gravitational mirror – where photons directed at the edge of the event horizon will bend around and come straight back at the source. As Kipping put it:“So the binary black hole is really a couple of giant mirrors circling around one another at potentially high velocity. The halo drive exploits this by bouncing photons off the “mirror” as the mirror approaches you, the photons bounce back, pushing you along, but also steal some of the energy from the black hole binary itself (think about how a ping pong ball thrown against a moving wall would come back faster). Using this setup, one can harvest the binary black hole energy for propulsion.” Image Credit: NASA/CXC/M.Weis This method of propulsion offers several obvious advantages. For starters, it offers users the potential to travel at relativistic speeds without the need for fuel, which currently accounts for the majority of a launch vehicle’s mass. There is also the many, many black holes that exist across the Milky Way, which could act as a network for relativistic space travel.What’s more, scientists have already witnessed the power of gravitational slingshot thanks to the discovery of hyper-velocity stars. According to research from the Harvard-Smithsonian Center for Astrophysics (CfA), these stars are a result of galactic mergers and interaction with massive black holes, which causes them to be kicked out of their galaxies at one-tenth to one-third the speed of light – ~30,000 to 100,000 km/s (18,600 to 62,000 mps).But of course, the concept comes with innumerable challenges and more than a few disadvantages. In addition to building spacecraft that would be capable of being flung around the event horizon of a black hole, there’s also the tremendous amount of precision needed – otherwise the ship and crew (if it has one) could end up being pulled apart in the maw of the black hole. On top of that, there’s the simply matter of reaching one:“[T]he thing has a huge disadvantage for us in that we have to first get to one of these black holes. I tend to think of it like a interstellar highway system – you have to pay a one-time toll to get on the highway, but once your on you can ride across the galaxy as much as you like without expending any more fuel.” The challenge of how humanity might go about reaching the nearest suitable black hole will be the subject of Kipping’s next paper, he indicated. And while an idea like this is about as remote to us as building a Dyson Sphere or using black holes to power starships, it does offer some pretty exciting possibilities for the future.In short, the concept of a black hole gravity machine presents humanity with a plausible path to becoming an interstellar species. In the meantime, the study of the concept will provide SETI researchers with another possible technosignature to look for. So until the day comes when we might try something like this out for ourselves, we will be able to see if any other species has already taken a stab at it and made it work!Source: Universe Today - Further Reading: Cool Worlds If you enjoy our selection of content please consider following Universal-Sci on social media:
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Cosmology & The Universe
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Clara Aldegunde goes on an intellectual journey to understand how quantum phenomena may thread together the fabric of space–time, giving rise to our reality (Clara Aldegunde) November 2021, Clara Aldegunde on Level 2 of the Central Library, Imperial College London, UK
I’m at the library, deeply engrossed in some research for my first article on quantum physics, when my phone rings and I snap back to reality. My parents are calling, and I hastily leave the silent study area to speak to them.
After the usual greetings and gossip, I can’t help but share with them what I’ve been learning. Some theorists, I’ve learned, think that quantum interactions are responsible for creating the space–time fabric of our universe. Using simplified models and mathematical tools, these researchers hope to explain how both space and time emerged. Although further investigation is vital to extrapolate this theory to a universe with the same characteristics as ours, this could be a promising first step towards quantum gravity and the long-sought “Theory of Everything”.
“Isn’t that exciting?” I ask my parents, who listen dumbfounded on the other end of the line. Carried away by the will to make them understand the incredibly deep implications of this concept, I find I have to begin by explaining the basics of quantum mechanics.
To truly get to grips with quantum mechanics, we must set aside our more classical mindset. Right now, there are two things I am sure of: I’m in South Kensington, London, standing at rest, explaining quantum mechanics to my family, and they are sitting on a sofa 2197 km away. If we were quantum particles, such as a proton and an electron, none of this would be true. In classical mechanics, we have definite answers when asked the position and momentum of a system at a given time. But cross the boundary from the classical to the quantum realm, and you’ll find, as physicists did in the early 20th century, that these rules break down.
At the quantum scale, one can never entirely accurately predict both the position of a particle, and its momentum, at a given time. And to describe any system, we need the wavefunction – a mathematical description of the quantum state of a system, which contains all its measurable information – to handle the probabilistic nature of quantum measurements. That’s why quantum particles are mathematically expressed in a way that embraces multiple possibilities, existing in a “superposition” of states at the same time. When we perform a measurement, the wavefunction collapses and picks a single definite value, corresponding to what we observe: a known definite measurement.
After giving my parents this rapid introduction, and suddenly thinking of the phone bill, I decide to go straight to the focal point of the article I’m working on: quantum entanglement. Too enthusiastic to wonder if they have been following my explanations so far, I try to clarify how this concept is “the characteristic trait of quantum mechanics, the one that enforces its entire departure from classical lines of thought” – just as Erwin Schrödinger declared almost 90 years ago (Math. Proc. Camb. Philos. Soc. 32 446).
Entanglement is a purely quantum-mechanical phenomenon, whereby two or more particles can have a closer relationship than is allowed by classical physics. It means that if we determine the state of one of particle, it instantaneously fixes the quantum state of the other(s), no matter how near or far they may be. It also means that if two such entangled particles are in a superposition of states, the collapse of the wavefunction of one of them means the instant co-ordinated collapse of the other. This strong correlation seems to transcend space and time, such that we can determine the state of one particle simply by measuring its entangled pair, no matter the distance between them. For example, if you know the spin of one particle, you can always determine that of the other. Could it be, perhaps, that it is this deep quantum connection between fundamental particles that threads together space and time?
But what are we ultimately looking for, and what would such a quantum space–time look like? Albert Einstein ousted Isaac Newton’s law of universal gravitation with his general theory of relativity (GR). It describes gravity as a geometric property of space–time, wherein the energy and momentum of matter and radiation directly determines the curvature of space–time – but GR is also formulated within the confines of classical physics. In an effort to unify quantum mechanics and gravity, researchers have long been on the hunt for a consistent theory of quantum gravity. One tempting solution is rooted in the aforementioned idea that, perhaps, the very fabric of space–time may be an emergent property of some kind of quantum entanglement; one that ultimately satisfies Einstein’s relativistic field equations.
“Doesn’t it feel like magic?” I ask my parents. Their bewildered silence doesn’t shake my enthusiasm. After I get off the phone and return to my desk, I picture myself as the pioneering theoretical physicists Juan Maldacena and Gerard ’t Hooft, thinking back to when they were on the precipice of discoveries that started to illuminate the links between the quantum world and space–time.
[Disclaimer: although the scientists featured below are real, the scenarios and quotes are fictional, imagined by the author for the purpose this article]
Building a quantum space–time
(Courtesy: Clara Aldegunde)
Gravity is a force that determines how objects interact with one another on a large scale. On a much smaller end of the scale – where gravity plays a near negligible effect – are the fundamental particles that make up everything in our universe, and their interactions are determined by the laws of quantum mechanics.
Quantum field theories are frameworks that combine classical field theory (which tells us how fundamental particles and fields interact), special relativity (which gives us an equivalence between space and time) and quantum mechanics. They apply to three of the four fundamental forces in the universe – the electromagnetic, strong and weak forces but not gravity.
Unfortunately, the general theory of relativity (GR) – which describes how gravity and space–time work in our universe – is not compatible with quantum mechanics. Indeed, GR says that space–time is continuous, whereas quantum mechanics dictates that everything is in discrete quantized packets of matter and energy.
To unify gravity and quantum mechanics, physicists and mathematicians have long been working on developing a theory of quantum gravity. In an attempt to show how a region of space–time with gravity could potentially be derived from a purely quantum theory, in 1997 Argentinian theoretical physicist Juan Maldacena proposed a conjectured link between two physical theories, which he dubbed the anti-de Sitter space/conformal field theory correspondence (AdS/CFT).
On the one hand are anti-de Sitter spaces (AdS) – a particular kind of space–time geometry that is used in theories of quantum gravity and is formulated in terms of string theory. On the other hand are conformal field theories (CFT) – a special version of quantum field theory that is invariant under conformal transformations. These transformations are such that the angles and velocities of a space–time are preserved and remain unchanged, despite any other changes, such as a change in scale. Unfortunately, this does not hold true for the quantum electrodynamics we observe in our universe, as a change in scale would impact the charges and energies of fundamental particles and fields, meaning that the quantum fields we observe in our reality are not described by conformal field theories.
Maldacena’s AdS/CFT correspondence postulates that these two theories provide two different descriptions of the same physical phenomena. In his proposed universe, the AdS is a space–time region that emerges, like a hologram, from the CFT, the gravity-free boundary of this holographic universe. Indeed, the 3D AdS has gravity, and is negatively curved (imagine a saddle shape), which allows it to have a boundary – the 2D CFT, which does not include gravity.
The lower-dimensional boundary is what gives rise to the so called “holographic principle” or duality that gives us two different ways of looking at the same system – just like in a hologram, where all of the 3D information is stored on a 2D surface. As the CFT has one fewer dimension than the AdS space, you can picture it as the 2D surface of a 3D cylinder – one where the quantum mechanics at play on surface includes all of the information of the bulk. And as it happens, it is the quantum entanglement in the boundary that gives rise to the space–time geometry in the bulk. January 1998, Juan Maldacena in the living room of his home near Harvard University, US
After a long day at work, you (Juan Maldacena) arrive home to find your two-year-old daughter in the living room, surrounded by her toys – miniature versions of everyday objects. You have just published a paper on how particular space–time geometries (“toy universes”) could be found to have certain correspondences to a type of quantum theory without gravity (more specifically known as a conformal field theory, CFT). And just as your daughter’s toys represent a version of reality that is much easier to handle, simplified versions of our universe make the problem of understanding the origins of space–time considerably more approachable.
Passionate about this beautiful symmetry, you start explaining to your daughter that her toys are just like anti-de Sitter space (AdS) – a multi-dimensional space–time with gravity that is used in theories of quantum gravity based on string theories. Indeed, AdS is the most used alternative space–time geometry to study this matter since you discovered the AdS/CFT correspondence (see box above).
By analysing this duality between a specific space–time geometry (easier to handle than our actual universe) and quantum mechanics, we have the right starting point to answer the most fundamental question of physics: what is space–time ultimately made of?
Your perplexed child looks on as you explain how even though an AdS universe is negatively curved and therefore is collapsing in on itself – as opposed to our positively curved and expanding universe – these simplified universes can be of enormous help when studying the physics behind quantum entanglement knitting space–time. “Solving challenging problems is much easier when you can divide them into not-so-challenging little parts,” you solemnly declare.
Nonetheless, there is still a huge conceptual roadblock: the maths of quantum physics operates in three dimensions, whereas space–time accounts for four. Luckily enough, your daughter need not be too concerned, as another theorist is already on the case.
1994, Gerard ’t Hooft in a lecture theatre at Utrecht University, Netherlands
You (Gerard ’t Hooft) are in your regular undergraduate lecture, surrounded by enthusiastic students who want you to explain to them a concept you introduced to the scientific community a year ago: the holographic principle. Developed as a solution for what happens when gravity, quantum mechanics and the laws of thermodynamics truly clash at the event horizons of black holes, the holographic principle suggests that a 4D space–time can be projected onto a 3D surface expressed by quantum mechanics. Just as a 2D array of pixels on a TV represents a 3D image, space–time can be mathematically described by this “hologram” in one fewer dimension.
The holographic principle suggests that 3D space could be threaded by fields that, when structured in the right way, generate an extra fourth dimension, giving rise to space–time. The lower-dimension hologram (3D quantum description) would serve as a frontier to the 4D bulk space, created thanks to entanglement on this boundary (figure 1). As the US theorist Ted Jacobson would later affirm in 1995, more entanglement would mean that parts of the hologram are more tightly connected, making deforming the space–time fabric more difficult, and leading to a weaker gravity as understood by Einstein.
1 Quantum holograms (a) The holographic principle related to AdS/CFT correspondence; information on space–time is stored as quantum information (qubits) of one less dimension (projected onto the walls). (b) Entanglement at the boundary connects different parts of the hologram. (Courtesy: Clara Aldegunde)
“But what would happen if we mathematically took out the entanglement from this quantum-mechanical description that we called a ‘hologram’?” you rhetorically ask your students. “Well, we find that the space–time splits up. As a matter of fact, if we remove all the entanglement, we are left with no space–time.”
Your students don’t seem convinced, so you decide to go a bit further, introducing the concept of entanglement entropy. This is a measurement of the amount of entanglement between two systems, and theorists have been able to directly relate it to the surface of the bulk, finding that it is proportional to the amount of entanglement.
But to be able to make this connection, you say that we need to consider a continuum of entanglements, leaving the idea of discrete connections behind. When we do this and let the entanglement in the hologram tend to zero, the bulk area (where space–time lives) also vanishes, as would happen if we were to take the threads off a piece of cloth (figure 2).
You pause for dramatic effect, meeting the eyes of your most eager students one by one, before you ask, “Isn’t this a strong argument supporting that space–time is indeed fundamentally quantum mechanical, being held together by entanglement between different parts of the hologram?”
25 December 2021, Clara Aldegunde in the dining room of her family home
“Finally, a well-deserved break,” I think in the middle of the family Christmas dinner when I overhear my dad describing my article as being about “some interaction between particles that, who knows how, forms space and time”. Suddenly, I feel the need to make my whole family understand how vital this hypothesis is for modern physics. Driven by my passion and all the recent knowledge I have absorbed, I decide to have another go at explaining these ideas to them by introducing the concept of a quantum bit, or qubit.
2 Pulling the threads Theoretical prediction of what would happen if entanglement between different parts of the hologram were removed. When mathematically reducing the amount of entanglement on the CFT surface, we find that space splits up (like pinching off a ball of clay). (Courtesy: Clara Aldegunde)
A qubit is a quantum system with two (or more) possible states. While classical bits can take a value of either 0 or 1, qubits (characterized, for example, by the spin of the quantum particle) have quantum properties and can exist in a superposition of the states. And if these qubits are entangled, knowing the state of one of them would mean knowing the state of the other, a concept that could be easily extended to a collection of any number of qubits.
Entangling each qubit with its neighbour would give rise to a completely entangled 2D network, and entangling two such networks would result in a 3D geometry. I then realize that this relates back to ’t Hooft’s ideas, as entangled qubits creating one more dimension beyond the number of dimensions they occur in explains the existence of the bulk and the boundary introduced by the holographic principle.
“But if two distant points of the hologram are entangled to form the space–time bulk in between, and information is travelling from one quantum particle to another instantly, wouldn’t this mean surpassing the speed of light?” asks my aunt who, to my delight, is following my explanation.
In fact, this conceptual problem can be solved by arguing that entangled particles do not really have to cover the space separating them. The speed of light can still be a physical limit, as long as we understand that entanglement does not occur in space–time, it creates space–time. Just as a rock or an orange are made up of atoms but don’t exhibit the properties of atomic physics, so the elements building space don’t need to be spatial, but will have spatial properties when combined in the right way.
Apart from my aunt, most of my family look confused and are unimpressed by my revelation. But I realize that this discussion has cleared up several ideas in my mind, as it dawns on me how quantum mechanics became a geometry that could now be compared to space–time.
Over the course of the holidays, I long to get back to my research into trying to discover the origins of space–time. I take a break from the family festivities and find a quiet room to think about Stanford University professor Monika Schleier-Smith, whose team is working on reverse-engineering highly entangled quantum systems in their lab, to see if some sort of space–time emerges. I ponder how, in 2017, Brandeis University physicist Brian Swingle came to the conclusion that “a geometry with the right properties built from entanglement has to obey the gravitational equations of motion” (Annu. Rev. Condens. Matter Phys. 9 345).
2015, Monika Schleier-Smith replying to Brian Swingle’s e-mail from her office at Stanford University, US
“Yes, Professor Swingle, I can reverse time in my lab,” you (Monika Schleier-Smith) say in reply to the very specific question from Brian Swingle. In your laboratory, you are working to control entanglement between atoms so precisely that it becomes possible to reverse their interactions, in the hope that you can experimentally create space–time in your lab.
Theoretical CFT models are often too complex to handle with existing mathematical tools, so trying to find their gravitational (AdS) dual in the lab could be the better option, potentially entailing the discovery of simpler systems than the ones being studied theoretically.
To be able to experimentally test this hypothesis of the origins of space–time, you decide to tackle the problem the other way around. Instead of starting from our universe and trying to explain it through quantum calculations, you study how controlling quantum entanglement may produce space–time geometry analogues that satisfy Einstein’s equations of general relativity.
The desired entanglement geometry forms a tree-like structure, where each pair of entangled atoms is entangled with another pair. The idea is that such individual, low-level entanglement is built up into a completely entangled system. Connecting various structures of this kind gives rise to the space–time bulk, thanks to a circle of connections between different parts of the CFT surface.
The key to observing this emergent space–time in the lab is to trap atoms with light to cause entanglement, and then control them using magnetic fields. To accomplish this, your laboratory is brimming with mirrors, fibre-optics and lenses around a vacuum chamber that contains rubidium atoms, cooled to fractions of a degree above zero kelvin. The entanglement is then controlled using a specially tuned laser and magnetic fields, allowing you to choose which atoms are getting entangled with each other.
This set-up seems to create holography in the laboratory – you can reverse time at the quantum scale. You realize the enormity of this finding. It will lend experimental support to Swingle’s theoretical work, and most importantly allow the scientific community to test the connections between quantum mechanics and gravity, bringing us one step closer to unifying modern physics.
9 January 2022, 23:00, Clara Aldegunde in her study at Imperial College London, UK
After almost two months of researching, discovering and learning, I have finally submitted my article. Concluding this work gave me answers to questions I hadn’t even thought of. More importantly, it left me with hundreds more questions.
Is this thread I am following leading us towards quantum gravity and a Theory of Everything, the ultimate goal of physicists? That is to say, would this quantum model be able to unify general relativity and quantum mechanics under one unique explanation, giving rise to a single theory able to describe our whole universe?
Is this thread I am following leading us towards quantum gravity and a Theory of Everything? The scientific community strongly supports this idea, and many physicists around the world are currently working on it, firmly expecting hints towards a unification theory. As I write in my recently finished paper, understanding entanglement as a geometrical structure would allow us to compare it to gravity and to check its correspondence with Einstein’s relativistic equations, thereby solving one of modern physics’ biggest quandaries.
Nonetheless, I’m left with the impression of having to make too many assumptions to connect quantum entanglement to the formation of the fabric of space–time. What am I missing, and what should I focus on as I begin my research career?
As I see it, the first problem to tackle would be to describe entanglement as the continuum version of discrete tensor metric in GR, which holds all the information about the geometric structure of a space–time. Once this is done, Einstein’s equations could be derived for this space–time model, explaining how gravity arises from entanglement for the simplified AdS space. The other key issue with an AdS universe is that its collapsing geometry looks nothing like our expanding universe, and several adjustments should be made to fully expand these findings to our reality.
Despite these open questions and concerns, this toy universe has provided both vital theoretical insights and the capacity to make some predictions; for example, volumes and areas scale the same way in AdS and in our universe.
What else can be done to illuminate the connection between entanglement and space–time? One idea would be to investigate more complex space–time structures, both mathematically (with tensor networks that, for example, represent black holes) or experimentally (as Schleier-Smith has only created simple space–time structures so far).
I remember the closing statement in Swingle’s paper: “Interestingly, the interior [of a black hole] continues to grow long after all entanglement entropies equilibrate, which is an observation that suggests ‘entanglement is not enough’.”
After reminding myself of all I have learned, I cannot help but feel extremely fulfilled. I let sleep take me, content in the knowledge that finishing my paper meant nothing but the beginning of my journey towards unmasking how the universe knits space–time.
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Cosmology & The Universe
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Binary black holes may be more stable than scientists had previously believed, with the action of dark energy accelerating the expansion of the universe and helping black holes in these binaries maintain a safe distance.
Black holes are regions of space around an infinitely dense "singularity" born from the collapse of a massive star. With masses many times that of the sun crammed into widths as small as 10 miles (16 kilometers), black holes have a gravitational pull so strong that not even light can escape a boundary around them, called the event horizon. And because massive stars are commonly found in binary pairs orbiting each other, black holes, too, often come in binary partnerships.
As these black holes move, they create gravitational waves — ripples in the fabric of space-time — and these waves carry angular momentum away from the system. This causes the black holes to spiral together, with gravity eventually taking over, causing the black holes to collide, merge and form a single, more massive black hole. Until now, scientists had thought that process was inevitable — meaning binary black holes are ultimately destined to become single solitary objects.
That's the case if the universe is static. However, since the early 1900s and the discovery by Edwin Hubble that galaxies are rapidly moving away from each other, scientists have known that the universe is expanding. Additionally, at the end of the 20th century, astronomers discovered that this expansion is actually accelerating, with the cause of the acceleration labeled "dark energy."
Dark energy accounts for as much as 68% of the energy and matter content of the cosmos, though scientists remain in the dark about what exactly it is.
"The standard model of cosmology assumes that the Big Bang brought the universe into existence and that, approximately 9.8 billion years ago, it became dominated by a mysterious force, coined 'dark energy,' which accelerates the universe at a constant rate," University of Southampton professor Oscar Dias, lead author of the new study, said in a statement.
Is two company for black holes?
The action of dark energy means that black holes sit in an ever-expanding fabric of space-time, leading the team to question if this expansion could help black hole pairings stay separated. They tackled the problem with some complex mathematical models and found that two non-rotating black holes could indeed exist in equilibrium, with the gravitational attraction between them counteracted by expansion.
"Viewed from a distance, a pair of black holes whose attraction is offset by cosmic expansion would look like a single black hole," Dias added. "It might be hard to detect whether it is a single black hole or a pair of them."
On the flip side of that, the gravitational attraction between the binary black holes would prevent the expansion of the universe from pushing the black holes too far apart.
The researchers think that their solution could be expanded to include rotating black holes, known officially as "Kerr black holes," and even more exotic black hole systems with more than two of these objects.
"Our theory is proven for a pair of static black holes, but we believe it could be applied to spinning ones, too," study co-author Jorge Santos, a researcher at the University of Cambridge in England, said in the same statement. "Also, it seems plausible that our solution could hold true for three or even four black holes, opening up a whole range of possibilities."
The team's research was published last month in the journal Physical Review Letters.
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Cosmology & The Universe
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Gravity doesn’t discriminate. An experiment in orbit has confirmed, with precision a hundred times greater than previous efforts, that everything falls the same way under the influence of gravity. The finding is the most stringent test yet of the equivalence principle, a key tenet of Einstein’s theory of general relativity. The principle holds to about one part in a thousand trillion, researchers report September 14 in Physical Review Letters. The idea that gravity affects all things equally might not seem surprising. But the slightest hint otherwise could help explain how general relativity, the foundational theory of gravity, meshes with the standard model of particle physics, the theoretical framework that describes all fundamental particles of matter. General relativity is a classical theory that sees the universe as smooth and continuous, whereas the standard model is a quantum theory involving grainy bits of matter and energy. Combining them into a single theory of everything has been an unfulfilled dream of scientists extending back to Einstein (SN: 1/12/22). Sign Up For the Latest from Science News Headlines and summaries of the latest Science News articles, delivered to your inbox “The equivalence principle is the most important cornerstone of Einstein’s theory of general relativity,” says Sabine Hossenfelder, a physicist with the Frankfurt Institute for Advanced Studies in Germany who was not involved in the study. “We know [it] eventually has to be altered because it cannot in its present form take into account quantum effects.” To help search for potential alterations, the MICROSCOPE experiment tracked the motion of nested metal cylinders — a 300-gram titanium outer cylinder and a 402-gram platinum inner one — as they orbited the Earth in near-perfect free fall. Any difference in the effect of gravity on the respective cylinders would cause them to move relative to each other. Small electrical forces applied to bring the cylinders back into alignment would have revealed a potential violation of the equivalence principle. From April 2016 to October 2018, the cylinders were shielded inside a satellite that protected them from the buffeting of solar winds, the minuscule pressure that sunlight exerts and the residual atmosphere at an orbital altitude of a little over 700 kilometers high. By performing the experiment in orbit, the researchers could compare the free fall of two different materials for extended periods without the confounding effects of vibrations or of objects nearby that could exert gravitational forces, says Manuel Rodrigues, a MICROSCOPE team member and physicist with the French aerospace lab ONERA in Palaiseau. “One of the lessons learned by MICROSCOPE is … that space is the best way to get an important improvement in the accuracy for this kind of test.” Over its two-and-a-half-year mission, MICROSCOPE found no sign of cracks in the equivalence principle, the new study reports. The finding builds on a previous interim report from the experiment that found the same thing, but with less precision (SN: 12/4/17). Some physicists suspect that limits to the equivalence principle may never turn up in experiments, and that Einstein will perpetually be proven right. Even 100 times greater precision from a follow-up MICROSCOPE 2 mission, tentatively planned for the 2030s, is unlikely to reveal an equivalence principle breakdown, says Clifford Will, a physicist at the University of Florida in Gainesville who is not affiliated with the experiment. “It really is still this basic idea that Einstein taught,” he says. What we see as the force of gravity is actually the curvature of spacetime. “Any body simply moves along the path in Earth’s spacetime,” whether it’s made of dense platinum, lighter titanium or any other material. But even if physicists never prove Einstein wrong, Hossenfelder says, experiments like MICROSCOPE are still important. “These tests aren’t just about the equivalence principle,” she says. “They implicitly look for all other kinds of deviations, new forces and so on,” that aren’t part of general relativity. “So really it’s a multiple-purpose, high-precision measurement.” Now that the mission is complete, the MICROSCOPE satellite will slowly spiral out of orbit. “It’s difficult to bet where in 25 years it will fall down,” Rodrigues says. Along with a reference set of platinum cylinders on board, “it’s [a] couple of millions of euros [in] platinum.” Where that precious platinum metal will land is anyone’s guess, but the gravity that pulls it down will tug on the titanium just as hard, to one part in a thousand trillion at least.
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Cosmology & The Universe
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The frontiers of astronomy are being pushed regularly these days thanks to next-generation telescopes and scientific collaborations. Even so, astronomers are still waiting to peel back the veil of the cosmic “Dark Ages,” which lasted from roughly 370,000 to 1 billion years after the Big Bang, where the Universe was shrouded with light-obscuring neutral hydrogen. The first stars and galaxies formed during this period (circa 100 to 500 million years), slowly dispelling the “darkness.” This period is known as the Epoch of Reionization, or as many astronomers call it: Cosmic Dawn.
By probing this period with advanced radio telescopes, astronomers will gain valuable insights into how the first galaxies formed and evolved. This is the purpose of the Hydrogen Epoch of Reionization Array (HERA), a radio telescope dedicated to observing the large-scale structure of the cosmos during and before the Epoch of Reionization located in the Karoo desert in South Africa. In a recent paper, the HERA Collaboration reports how it doubled the array’s sensitivity and how their observations will lead to the first 3D map of Cosmic Dawn.
The HERA Collaboration is an international consortium comprised of astronomers and astrophysicists from South Africa, Australia, the United States, the United Kingdom, Israel, Italy, and India. The research was led by Joshua Dillon, a research scientist at UC Berkeley’s Department of Astronomy and the lead author of the paper. The paper that describes their research and findings recently appeared online and has been accepted for publication by the Astrophysical Journal. Their results provide new insight into how reionization occurred in the early Universe.
From Dark to Dawn
Based on current cosmological models, the Universe began 13.8 billion years ago with the Big Bang, which produced a flurry of energy and elementary particles that slowly cooled to create the first protons and electrons (which combined to form the first hydrogen and helium atoms). The leftover “relic radiation” is observable today in the form of the Cosmic Microwave Background (CMB). Thanks to missions like the COBE, WMAP, and Planck, astronomers have mapped the faint variations in temperature that existed 380,000 years after the Big Bang.
Meanwhile, thanks to missions like Hubble, astronomers have observed galaxies as they existed roughly 1 billion years after the Big Bang (circa 13 billion years ago). This has led to a greater understanding of how galaxies evolved and the possible role of Dark Matter and Dark Energy in the process. However, there is a gap between these observations of the CMB and early galaxies: the aforementioned “Dark Ages” (circa 370,000 to 1 billion years after the Big Bang). This epoch cannot be studied with conventional telescopes because photons in this period were either part of the CMB or those released by neutral hydrogen atoms — the 21-centimeter hydrogen line.
As the first stars and galaxies gradually formed, the intense radiation they emitted reionized much of the surrounding Universe. This led to the Epoch of Reionization, where neutral hydrogen began to form clouds of plasma of free electrons and protons. To map these bubbles, HERA, and other sophisticated radio telescopes were created to observe the hydrogen line (which has a frequency of 1,420 megahertz). This wavelength of light is one that neutral hydrogen absorbs and emits, but ionized hydrogen does not.
Since the Epoch of Reionization, this radiation has been redshifted by the expansion of the Universe to a wavelength of about 2 meters (6 feet). HERA’s simple antennas, built from chicken wire, PVC pipe, and telephone poles, are 14 meters (46 feet) in diameter, allowing them to focus this radiation onto detectors. The backend is where things get sophisticated, consisting of a supercomputer and machine learning algorithms performing advanced data analysis. This map could track galactic evolution from the very early Universe to today.
The Earliest Stars
The team’s results showed that the earliest stars, which may have formed around 200 million years after the Big Bang, contained few other elements than hydrogen and helium. The finding is consistent with accepted models of stellar evolution, which state that metals (from lithium to uranium) formed within the first generation of stars. When these stars collapsed after a comparatively short lifespan (hundreds of millions of years rather than billions), these metals were shed with the stars’ outer layers, seeding the Universe with metals that became part of subsequent generations of stars.
Astronomers are interested in the atomic composition of these early stars since this would show how long they took to heat the intergalactic medium (IGM) and cause reionization to occur. A key element here is high-energy radiation (primarily X-rays) produced by binary stars once one of them goes supernova, collapsing into a black hole or neutron star and eventually consuming their companion. Since the earliest stars had very few heavy elements (low metallicity), they would not have heated the surrounding region much and produced fewer X-rays.
Ultimately, the HERA Collaboration did not find the signal these bubbles would have emitted in the data. According to Aaron Parsons, the principal investigator for HERA, an associate professor of astronomy at UC Berkeley, and the director of its Radio Astronomy Laboratory, this rules out some theories of how stars evolved in the early Universe. “Early galaxies have to have been significantly different than the galaxies that we observe today for us not to have seen a signal,” he said. “In particular, their X-ray characteristics have to have changed. Otherwise, we would have detected the signal we’re looking for.”
The absence of the signal largely rules out the “Cold Reionization” theory, which posits that reionization had a colder starting point. Instead, the HERA researchers suspect that the X-rays from binary stars heated the intergalactic medium (IGM) first. Said Joshua Dillon, a research scientist at UC Berkeley’s Department of Astronomy and lead author of the paper:
“Our results require that even before reionization and by as late as 450 million years after the Big Bang, the gas between galaxies must have been heated by X-rays. These likely came from binary systems where one star loses mass to a companion black hole. Our results show that if that’s the case, those stars must have been very low ‘metallicity,’ that is, very few elements other than hydrogen and helium in comparison to our sun, which makes sense because we’re talking about a period in time in the Universe before most of the other elements were formed.”
These findings agree with the preliminary results from the first analysis of HERA data (reported last year) that hinted that alternative theories like “Cold Reionization” were unlikely. These results were based on 18 nights of observation by Phase I of the HERA project (about 40 antennas) and were the most sensitive observations of the early Universe to date. This latest is based on 94 nights of Phase I observations (between 2017 and 2018) and demonstrates how the HERA team has improved the array’s sensitivity.
This includes a 2.1-factor increase for light emitted about 650 million years after the Big Bang (a redshift value (z) of 7.9) and a 2.6-factor increase for radiation emitted about 450 million years after the Big Bang (z=10.4). This represents a great step forward for the project and astronomers’ understanding of the early Universe. According to Eloy de Lera Acedo, an astrophysicist from the University of Cambridge’s Cavendish Astrophysics, these latest observations are the “best evidence we have of heating of the intergalactic medium by early galaxies.”
What’s next
The HERA team continues to improve the telescope’s calibration and data analysis in the hopes of seeing the predicted ionization bubbles in the early Universe. Filtering out the local radio noise to see the radiation of the early Universe remains a challenge since the radio emissions from this era are about one-millionth the intensity of radio noise in the vicinity of Earth. When all of HERA’s radio dishes are online and fully calibrated, the team hopes to construct a 3D map of the ionized and neutral hydrogen bubbles from ca. 200 million to 1 billion years after the Big Bang.
Once that is complete, the HERA Collaboration and other astronomers expect to see a “Swiss-cheese” pattern in the early Universe, where galaxies make holes in a neutral hydrogen background. Said Dillion:
“This is moving toward a potentially revolutionary technique in cosmology. Once you can get down to the sensitivity you need, there’s so much information in the data. A 3D map of most of the luminous matter in the Universe is the goal for the next 50 years or more. What we’ve done is we’ve said the cheese must be warmer than if nothing had happened. If the cheese were really cold, it turns out it would be easier to observe that patchiness than if the cheese were warm.”
Other cutting-edge telescopes are allowing astronomers to peer into the early Universe. This includes the Canadian Hydrogen Intensity Mapping Experiment (CHIME) in British Columbia, which also observes the 21-cm hydrogen line to study how the Universe evolved. There’s also the James Webb Space Telescope, which observed a galaxy that existed about 325 million years after the Big Bang this past summer. This established a new record for the earliest galaxy ever observed. However, the JWST can only observe the brightest galaxies from this epoch, while arrays like HERA and CHIME continue to probe the “darker” regions of the early Universe.
“HERA is continuing to improve and set better and better limits,” said Parsons. “The fact that we’re able to keep pushing through, and we have new techniques that are continuing to bear fruit for our telescope, is great.”
This article was originally published on Universe Today by Matt Williams. Read the original article here.
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Cosmology & The Universe
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On Tuesday afternoon, we were treated to some of the most detailed images of the universe that anyone has ever seen. The pictures were the first to be released from the James Webb space telescope (JWST) and were greeted with joy by astronomers and journalists. The former because the images demonstrated that the telescope was working and the latter because the pictures would be much more pleasing to view on a newspaper’s front page than the candidates for leadership of the Conservative party.The first images are, literally, wonderful. Specialist astronomers can see details of the birth and death of stars, as well as all the stages in between; and witness gravitational lensing, predicted by Einstein, previously only partially recorded by the JWST’s predecessor, the Hubble space telescope (HST). They continue to rhapsodise about the number and diversity of exoplanets – planets outside the solar system – that the JWST should find, and how instruments on the telescope will be able to detect and analyse exoplanetary atmospheres. The first signature of life on a planet beyond the solar system might be recorded by the JWST.These discoveries are important and hugely significant – for astronomers and astrophysicists. But how important is the JWST for the much greater number of people for whom the closest they get to the study of stars is a daily read of their horoscope? It is true that increasing the sum of human knowledge is a Good Thing. And that understanding the origin of the universe and the potential for life beyond Earth are questions that drive many scientists (myself included). But is the £8.4bn price tag worth it? What might come from the JWST that benefits us all?For a start, there is the inspirational value of the images. The simple joy in appreciating their beauty. The colour and texture of the pictures we have seen bring to (my) mind works by some of the finest artists. What would Turner or Monet have been moved to paint if they could have seen the JWST’s shot of the Carina Nebula? How might contemporary artists, including poets and musicians, be inspired by the JWST, enriching all of us with their interpretations?There are, though, more practical benefits that have already come from the telescope. The real heroes in the JWST story are not the scientists who will interpret the results. Not even the instrument specialists who designed and built the equipment that will detect planets, stars and galaxies. The heroes are the engineers and technologists who built the telescope. If the JWST is pushing the limits of how far back in time cosmologists can see, it has been enabled by engineers pushing at the limits of technology. And whenever technologies advance in one field, opportunities to apply those advances elsewhere inevitably follow.What advances have (so far) been recognised from the JWST? There are at least two that have resulted from the design of the mirror, the 6.5m gold-plated array of hexagons. In simple terms, a telescope is a bucket to collect radiation – the bigger the bucket, the more radiation can be collected in a period of time. The first picture released from the JWST was of a cluster of galaxies with the less than memorable name SMACS 0723. It had taken just over 12 hours to collect – in comparison with a less distinct version of a similar region produced over several weeks by the 2.4m-wide HST. So, the bigger your bucket – or the wider your mirror – the faster you can obtain an image.An image from the Mid-Infrared Instrument (Miri) on the James Webb space telescope shows details of Stephan’s Quintet, a visual grouping of five galaxies. Photograph: NASA/AFP/Getty ImagesThe mirror on the JWST is made from beryllium, a metal that is much lighter than aluminium or glass. It was fabricated as 18 hexagonally shaped plates, and it is from these plates that the first technological spin-out was recognised. The plates have to be flat. Really, really flat, as any distortion would ruin the ability of the telescope to produce useful results. And, remember, the JWST is about a million miles away from Earth, so if anything goes wrong, it cannot be fixed by physical additions to the structure.The engineers developed an improved sensor to measure how light scattered from the front of the mirror – in effect, looking for humps and bumps in the surface that were less than the width of a human hair in size. This technology has now been implemented in the health sector, for looking for irregularities in the shape of an eye, allowing more rapid diagnosis of ocular problems. It is anticipated that the sensor will also find many other uses – such as detection of swelling in blood vessels and impurities in semi-conductors.Second, once the JWST arrived at its designated station, the array was unfolded. Each segment had to be aligned, using tiny motors (actuators) to push them into position. Again, the precision required to align the mirrors correctly was to less than the width of a human air. Actuators are widely used in many sectors – and the design of a new generation of even smaller, automatically controlled motors has a range of applications, starting with precision-positioning of surgical instruments through to life detection in hazardous situations. There will doubtless be other benefits, and the beauty of the images will always be with us.One final thought. It might have escaped your notice, but I have not referred to Nasa’s JWST. This is because it is not Nasa’s JWST. It was designed and built by a consortium: the European and Canadian space agencies (ESA and CSA, respectively) working alongside Nasa.As part of our membership of ESA, the UK played a major role in the design and build of Miri, the Mid Infrared Instrument on the JWST. The UK has a thriving space industry, with government figures showing it added some £16.5bn to our economy in 2019/20 – sufficient for us to launch two JWSTs of our own. The space sector has a positive growth forecast, despite a shrinking economy, and that’s worth a lot more than any horoscope predictions about gifts from the stars.
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Cosmology & The Universe
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In April 2023, scientists from the Atacama Cosmology Telescope (ACT) collaboration created a map of the universe showing the detailed distribution of dark matter, a mysterious form of matter that makes up around 85% of the total matter in the universe (opens in new tab).
While creating any accurate map of matter distribution across the cosmos is an impressive feat, it is particularly extraordinary for dark matter, which does not interact with light and thus cannot be seen directly with telescopes or other instruments.
So, if dark matter is effectively "invisible," how can scientists map it? And how do we even know dark matter exists? Put simply, to detect dark matter, astronomers look at its indirect effects on gravity and how it impacts other objects with mass and light.
Related: Latest dark matter news
All galaxies are believed to be wrapped in an invisible halo of dark matter, and this envelope is vitally important; galaxies are rotating so rapidly, that without dark matter, they would have been torn apart long ago if they were held together only by the influence of their stars, gas, dust and planets, according to the European Organization for Nuclear Research (opens in new tab) (CERN). As such, this mysterious substance must have played an important role in the evolution of the universe.
What makes dark matter "invisible"?
Everything we see around us on a day-to-day basis is made up of "ordinary" matter, known as baryonic matter, meaning it's composed of baryons (such as protons and neutrons). According to the Swinburne Centre for Astrophysics and Supercomputing (opens in new tab), cosmic objects made of baryonic matter include clouds of cold gas, planets, comets and asteroids, stars, neutron stars and even black holes.
Most of these cosmic objects (as well as Earthbound objects, such as tables, cars and cats) can be seen because baryons interact with the electromagnetic force, one of the universe's four fundamental forces. When electromagnetic radiation, including visible light, falls on baryonic objects, they absorb photons and reemit them, or simply reflect them, so these objects can be seen. Even dark clouds of cosmic gas that do not shine brightly absorb photons of light at certain wavelengths, so they can be seen by their interaction with light.
Scientists know that dark matter is distinct from ordinary baryonic matter because whatever particles dark matter comprises either don't reflect, absorb or emit electromagnetic radiation or if they do interact with light, they do so incredibly weakly. This means dark matter can't be seen in traditional ways that rely on electromagnetic radiation.
How do scientists know dark matter is there?(opens in new tab)
Although dark matter does not interact strongly via electromagnetism, it does interact with another fundamental force: gravity. It is through the interaction with gravity that astronomers were first able to discover dark matter and, later, accurately map it.
The first hints of dark matter were observed in 1933 when California Institute of Technology astronomer Fritz Zwicky (opens in new tab) used the Mount Wilson Observatory to measure the visible mass of the Coma Cluster of galaxies. Zwicky, later dubbed "the father of dark matter," found that single galaxies in this cluster were moving too fast for the cluster to remain together based on the gravity of the visible matter alone.
Zwicky suggested that an as-yet-unobserved type of mass — "dunkle Materie," or "dark matter" — might explain this disparity, but the concept wouldn't be widely accepted for decades to come, until after his death in 1974.
While studying the rotational dynamics of galaxies, Carnegie Institution astronomer Vera Rubin became the next scientist to infer the presence of dark matter with observations that helped to cement it as an accepted element of the universe. Rubin saw that the stars at the edge of spiral galaxies far from their dense centers were moving as fast as stars closer to the galactic heart, according to the American Museum of Natural History (opens in new tab).
This was odd, as the visible mass of these galaxies shouldn't have enough gravitational influence to keep stars moving rapidly in sparsely populated outer regions in place. This meant that there had to be a huge amount of invisible matter in the outer regions of galaxies away from dense stellar populations. Rubin calculated that visible matter in the galaxies she observed must account for just 10% of their mass, and when revisiting Zwicky's findings from around four decades before, she discovered that a similar ratio of seen and unseen matter binds the Coma Cluster.
Since the 1970s and Rubin's discovery, astronomers have been using the gravitational influence of dark matter on the very fabric of space to better infer the location of dark matter. They theorize that filaments of dark matter link clumps of this mysterious substance, forming a vast cosmic web containing clusters of galaxies.
Mapping dark matter with a little help from Einstein
To map dark matter, astronomers use Albert Einstein's 1915 theory of general relativity, which states that gravity arises from objects with mass shaping the very fabric of time and space. This phenomenon affects the objects in space, energy and even light. As theoretical physicist John Wheeler once famously and succinctly said about general relativity (opens in new tab), "Space-time tells matter how to move; matter tells space-time how to curve."
To understand the effect of mass on space, it may be helpful to look to a commonly cited analogy. Imagine placing objects of various masses on a stretched rubber sheet. The more mass one of these objects has, the more it warps the sheet. That means very massive cosmic objects, like galaxies, have considerable effects on the fabric of space.
Astronomers can measure this effect — and thus the mass of an object and how matter is distributed through it — using light that passes through this warped space. Light always travels in a straight line, but massive objects can cause the warping the space the path of light traveling through it is bent and is thus distorted. This phenomenon, known as gravitational lensing, is useful for detecting very faint objects, such as distant galaxies. It also allows astronomers to map dark matter, which has mass and, therefore, warps space-time and can indirectly affect the passage of light. By looking at how galaxies and galactic clusters cause light to bend, astronomers can calculate the mass of visible matter and its effect on this process and then estimate the amount of dark matter and how it is distributed.
Mapping dark matter with a cosmic fossil(opens in new tab)
The dark matter map created by the ACT collaboration covers a quarter of the sky visible over Earth and extends deep into the universe. To create this model and show the large-scale distribution of dark matter, the team needed to look at distortions in the cosmic microwave background (CMB). The CMB is the oldest form of light in the universe, created during an event called "the last scattering (opens in new tab)", which occurred around 380,000 years after the Big Bang. At this time, the universe was hot and dense, but as it expanded and cooled, it reached a temperature at which electrons could bind to protons to form the first atoms.
Until this point, electrons had been endlessly scattering photons. This meant light couldn't travel, so the universe was opaque. With free electrons snatched up and bound to protons, light could finally travel freely, and the universe instantly became transparent.
Because this first light was emitted when the universe was a fraction of its current size, it fills the universe with an extremely high degree of uniformity. Therefore, by looking at distortions in this first light caused by gravitational lensing, ACT scientists could measure the distribution of dark matter.
In addition to fitting the picture of the universe and dark matter suggested by general relativity and the standard model of cosmology, these highly accurate measurements could lead to a deeper understanding of dark matter.
Mapping dark matter FAQs answered by an expert
We asked Renée Hložek, an associate professor at the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto and a contributing member at the Atacama Cosmology Telescope collaboration, some questions about the mapping of dark matter.
Renée Hložek is an associate professor at the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto and a contributing member of the Atacama Cosmology Telescope collaboration.
What makes dark matter effectively "invisible"?
Dark matter is effectively invisible because it is "weakly interacting" with light. One of the ways we "'see" matter is if it makes its own light (like the sun) and if light bounces off its surface (as it does off your skin). The fact that dark matter is weakly interacting with light means that this process occurs only very, very rarely (or maybe not at all!), so it appears effectively "invisible" to us when looking with light. Searching for signs of dark matter is one of the biggest research areas in modern cosmology.
If dark matter doesn't interact with light, how do we know it's there?
The amazing thing is that matter interacts in other ways not related to light. It interacts gravitationally (just as you and I, and the sun, etc. do). This gravitational interaction means that it bends/curves the space around it as predicted by Einstein's theory of general relativity. To use the analogy of the sun, the sun is a massive object, and it bends the space around it. The Earth moves in that space around the sun in an orbit on a "geodesic" in this space. If you replaced the normal matter of the sun with dark matter, you wouldn't see any light from the sun, but Earth's orbit would continue unchanged!
Why is the gravitational influence of dark matter important?
The reason why this gravitational influence of dark matter is so cool is that we can exploit this fact to "'see" it in the sky. When a massive object distorts the space around it through its gravitational interaction, it means that objects will travel on geodesics in that curved space around the object. Just as the Earth's path is "bent" into an orbit, light will also be bent by the massive object. That means we can use the bending of light to detect the presence of dark matter with mass that isn't shining like "normal" matter.
This bending of light is actually one of the ways that Einstein's theory was first tested in the early 20th century. During the 1919 solar eclipse, when the normal shining light of the sun was blocked by the moon, the projected positions of stars close to the sun on the sky were recorded and they were slightly shifted because the light from those stars was being bent by the sun.
How can we use this to "map" dark matter?
In our case, the ACT collaboration is measuring the very small bending or deflections of light that originated a few hundred thousand years after the Big Bang, from a time we call "recombination," because the protons and electrons in the universe recombined to be neutral atoms. We call this light the cosmic microwave background, or CMB. The dark matter in the universe between us and that time of recombination very slightly bends, or "lenses," the CMB light. It's a really subtle effect, and so our team has developed sophisticated tools to measure the lensing deflection signal of the CMB light and use it to infer, or "see," the integrated dark matter.
What have we learned about the universe by creating these dark matter maps?
Partly, we confirm that there must be something massive bending the light of the CMB — which may sound like "We confirmed it is there," but it's actually more profound. Some folks don't like dark matter as a concept and try to explain other pieces of evidence for dark matter (like the rotation curves of galaxies) by suggesting that perhaps light itself is behaving differently in those systems. But seeing this map of the dark matter we infer from its lensing signal makes those arguments for light behaving weirdly much harder to swallow. It is a beautiful prediction of general relativity, and to see it mapped across the sky is breathtaking! This same theory (general relativity) makes predictions for how the universe will change in the future, and so any adjustments to this theory or the parameters within it that we can make through observations is key to understanding the eventual fate of the universe — or, as I like to think of it, how this movie is going to end.
Additional resources
Vera Rubin is considered the "mother of dark matter." Read about her work to uncover this mysterious form of matter on this page from the American Museum of Natural History (opens in new tab). The cosmic microwave background was integral to this latest map of dark matter. Read more about the CMB from these resources (opens in new tab) from the European Space Agency.
Bibliography
American Museum of Natural History. (2000). Vera Rubin and dark matter. In Soter, S. & deGrasse Tyson, N. (Eds.), Cosmic horizons: Astronomy at the cutting edge. New Press.
CERN. (n.d.). Dark matter. Retrieved April 28, 2023, from https://home.cern/science/physics/dark-matter (opens in new tab)
Clavin, W. (2020, October 23). Where is dark matter hiding? Caltech Magazine. https://magazine.caltech.edu/post/where-is-dark-matter-hiding (opens in new tab)
De Swart, J. (2019, September 3). Deciphering dark matter: The remarkable life of Fritz Zwicky. Nature. https://www.nature.com/articles/d41586-019-02603-7 (opens in new tab)
Overduin, J. (2007, November). Einstein's spacetime. Gravity Probe B: Testing Einstein's Universe. Stanford University. https://einstein.stanford.edu/SPACETIME/spacetime2.html (opens in new tab)
Swinburne University. (n.d.). Baryonic matter. Cosmos: The SAO Encyclopedia of Astronomy. Retrieved April 28, 2023, from https://astronomy.swin.edu.au/cosmos/b/Baryonic+Matter (opens in new tab)
U.S. Department of Energy. (n.d.). DOE explains … dark matter. Retrieved April 28, 2023, from https://www.energy.gov/science/doe-explainsdark-matter (opens in new tab)
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Cosmology & The Universe
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What's happening Astronomers have recorded the longest-lasting fast radio burst, or FRB, yet from a distant galaxy. Why it matters The powerful burst of radio waves could help solve many mysteries of the cosmos, including the origins of FRBs themselves. Among the newer mysteries of the cosmos are fast radio bursts, or FRBs: intense, bright blasts of radio waves from the other side of the universe that typically last just a few milliseconds. Now scientists have detected the longest-lasting FRB yet, which resembles something more like a celestial pulse than a fleeting alien blip. "It was unusual," Daniele Michilli, a researcher at MIT, recalled in a statement. "Not only was it very long, lasting about three seconds, but there were periodic peaks that were remarkably precise, emitting every fraction of a second -- boom, boom, boom -- like a heartbeat. This is the first time the signal itself is periodic." Though three seconds may still seem fleeting, it's about a thousand times longer than the typical FRB. Within that short timeframe, the signal would peak every fifth of a second in a clear pattern. "There are not many things in the universe that emit strictly periodic signals," explains Michilli. "Examples that we know of in our own galaxy are radio pulsars and magnetars, which rotate and produce a beamed emission similar to a lighthouse. And we think this new signal could be a magnetar or pulsar on steroids." Now playing: Watch this: Repeating radio signals coming from space 1:30 It makes sense that the source of the signal would be something mind-bendingly powerful like a neutron star. Pulsars and magnetars are both types of neutron stars, which are the extremely dense collapsed cores of giant stars that spin rapidly in deep space while emitting periodic blasts of energy. In this case, those bright blasts likely traveled several billion light-years from a distant and ancient galaxy to be picked up by the Canadian Hydrogen Intensity Mapping Experiment, or Chime, a special type of radio telescope in British Columbia. The signal is labeled FRB 20191221A and a paper on the discovery authored by the Chime/FRB Collaboration and dozens of co-authors is published in this week's issue of the journal Nature. We've known about the existence of FRBs only since 2007, and so far FRBs that repeat or demonstrate any sort of pattern have been quite rare. Deepening the mystery around FRB 20191221A is the fact that the signal looks to be about a million times stronger than the radio bursts we'd expect to see from pulsars and magnetars in our own galaxy. This could be because it came from some monster object in the deep cosmic past that's normally obscured, or perhaps a more typical object just threw off a onetime series of remarkably brilliant bursts for an unknown reason. "This detection raises the question of what could cause this extreme signal that we've never seen before, and how can we use this signal to study the universe," Michilli says. "Future telescopes promise to discover thousands of FRBs a month, and at that point we may find many more of these periodic signals." Those signals can be used as tools to investigate even bigger mysteries, like the expansion of the universe and the life cycles of stars.
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Cosmology & The Universe
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12 min agoNASA released the 1st Webb Telescope image yesterday — and more are coming todayFrom CNN's Ashley StricklandThe first image from the James Webb telescope, released on Monday, July 11. (NASA/ESA/CSA/STScI)NASA on Monday released the first image from the James Webb Space Telescope. NASA called the image "the deepest & sharpest infrared image of the early universe ever taken." The image depicts a massive group of galaxy clusters that act as a magnifying glass for the objects behind them. Called gravitational lensing, this will create Webb's first deep field view of incredibly old and distant, faint galaxies. The rest of the images will be released today. The series of pictures as a whole is likely to include a new look at five cosmic targets.16 min agoScientists hope Webb will be the first step in identifying signs of life in spaceFrom CNN's Ashley StricklandCould there be life in space? Scientists hope the James Webb Space Telescope will help them get closer to the answer.Astronomers have yet to find a solar system quite like ours. And of the thousands of known exoplanets, none quite match up with the planets in our cosmic backyard. But scientists have only just begun to scratch the surface of these planets outside the solar system. The next step is looking inside of them.Webb will peer into the very atmospheres of exoplanets, some of which are potentially habitable. Since the first exoplanets were discovered in the 1990s, many have wondered if we might find another Earth out there, a place called Planet B.So far, the study of these bodies hasn't revealed another Earth, and it's unlikely that even with technology like the Webb, there won't be "a true Earth analog" out there, said Klaus Pontoppidan, Webb project scientist at the Space Telescope Science Institute in Baltimore. Signs of life: The Webb telescope will look inside the atmospheres of exoplanets orbiting much smaller stars than our sun. These planets are connected with an intriguing idea: What if life happens differently outside of Earth? And it's something that the successors of this telescope could investigate in the decades to come.In fact, the task of identifying signs of life on other planets is already slated for future telescopes, like the one outlined in the recently released Astro2020 decadal survey that will look at 25 potentially habitable exoplanets."I kind of really want us to be able to find life on something that looks not a lot like Earth," said Nikole Lewis, astrophysicist and an assistant professor of astronomy at Cornell University.Life, as we understand it, needs energy, liquid and the right temperature, she said. What happens when a potential sign of life is detected? Finding the sign is fantastic — and figuring out the next step is crucial, said Sara Seager, an astrophysicist, planetary scientist and professor at the Massachusetts Institute of Technology.If it's determined that there was no other way a potential sign of life could be created, collaboration will be a key aspect, Lewis said. Engaging with chemists, biologists and people of different disciplines outside of astronomy and planetary science can determine the path forward."My hope is that we'll be careful, and that we will engage with all of the relevant experts to try to understand if this is in fact, a signature that could only mean that life is on this planet, and then hopefully announced such a thing to the public," Lewis said.Jill Tarter, astronomer and former director of the Center for SETI Research, believes that the answer to finding life may rely on technosignatures, rather than biosignatures, because the evidence of past or present technology is "potentially a lot less ambiguous."Biosignatures could be gases or molecules that show signs of life. Technosignatures are signals that could be created by intelligent life.Read further about the search for life in space here.Watch more: 20 min agoThe Webb telescope was built to look at the structure of the universe itself. Here's what to know about it.From CNN's Ashley StricklandThe James Webb telescope on March 5, 2020. (Chris Gunn/NASA)In addition to investigating the wealth of planets outside of our solar system, the James Webb Space Telescope is peering back to some of the earliest galaxies that formed after the Big Bang and the very structure of the universe itself.Launched in December, the Webb is allowing researchers to get four times closer to the Big Bang than the Hubble Space Telescope, according to Marcia Rieke, a regents professor of astronomy at the University of Arizona's Steward Observatory and principal investigator for the Near Infrared Camera on the Webb telescope. Hubble observed the universe 450 million years after the Big Bang.Each space telescope builds on the knowledge gained from the previous one. In the case of Webb, its mirror is nearly 60 times larger than previous space telescopes, including the retired Spitzer Space Telescope. The observatory also improves on the sensitivity and resolution of the Hubble.Collecting infrared observations from space prevents interference created by the heat from our planet and its atmosphere. These observations could confirm or entirely upend predictions and ideas that scientists have about the origin of the universe and how it evolved.Here are some other things to know about the Webb telescope:A massive mirror: The telescope comes equipped with a mirror that can extend 21 feet and 4 inches (6.5 meters) — a massive length that will allow the mirror to collect more light from the objects it observes once the telescope is in space. The more light the mirror can collect, the more details the telescope can observe. The mirror includes 18 hexagonal gold-coated segments, each 4.3 feet (1.32 meters) in diameter. It's the largest mirror NASA has ever built, the agency saidSuper sunshield: The spacecraft includes a five-layer sunshield that unfurled to reach the size of a tennis court. It will protect Webb's giant mirror and instruments from the sun's heat because they need to be kept at a very frigid negative 370 degrees Fahrenheit (negative 188 degrees Celsius) to operate. Scientists say this allows it to look at things that were out of reach before.Key wavelengths: Key questions about the universe can be answered when scientists have access to data from different wavelengths of light — something scientists really started looking at in the last 70 years. Before that, "all astronomy was done in optical (visible light) and looking at the universe in optical is like going to the symphony concert and only listening to one note. Now, we've got the whole symphony," said George Rieke, a regents professor of astronomy at the University of Arizona's Steward Observatory who worked on Webb as the science team lead for the telescope's Mid-Infrared Instrument.38 min agoThe first photos from the Webb telescope come after decades of workFrom CNN's Ashley StricklandThe James Webb Space Telescope is the most powerful telescope ever built — a moment that has been decades in the making.The telescope, which includes instruments from the Canadian Space Agency and the European Space Agency, has endured years of delays, including a combination of factors brought on by the pandemic and technical challenges.Here are some of the key dates:1989: The concept for Webb was first imagined as a successor to the Hubble telescope at a workshop.2004: Construction began on Webb. Thousands of scientists, technicians and engineers from 14 countries have spent 40 million hours building.2018: The telescope was initially planned to launch in 2018, but endured years of delays, including a combination of factors brought on later by the pandemic and technical challenges.December 2021: The previous launch date of Dec. 18 was pushed to Dec. 22 after technicians were preparing to attach the telescope to the upper stage of the rocket when "a sudden, unplanned release of a clamp band caused a vibration throughout the observatory," according to the agency. After testing and reviewing the observatory, teams concluded that the telescope was not damaged. After another delay, weather pushed the launch back again one more day from Dec. 24 to Dec. 25.Dec. 25, 2021: The telescope successfully launched from Europe's Spaceport in French Guiana.Dec. 26, 2021: Webb released its antenna assembly, including a high-data-rate dish antenna, that will serve as the telescope's way of sending back 28.6 gigabytes of science data twice a day. Once it is in orbit, Webb will continue to communicate with teams on Earth and the space observatory using the Deep Space Network, which is composed of three massive antenna ground stations in Australia, Spain and California.January 2022: Webb reached it final destination in space and unfurled its tennis court-size sunshield and unfolded a massive gold mirror. It is in an orbit called the second sun-Earth Lagrange point, or L2. This vantage point is ideal for Webb because the gravitational forces of the sun and Earth will basically ensure the spacecraft doesn't have to use much thrust to stay in orbit. And it will allow the telescope to have an unimpeded view of the universe, unlike the Hubble Space Telescope, which moves in and out of Earth's shadow every 90 minutes.March 2022: Webb completed a series of tests to make sure it was working as expected. The team didn't encounter any issues and determined that Webb can observe light from distant objects and feed that light into the science instruments aboard the observatory.May 2022: One of the 18 golden segments of the James Webb Space Telescope's giant mirror was hit by a micrometeoroid. Spacecrafts don't have a protective bubble of atmosphere around them like the Earth does, so it's almost impossible to avoid these impacts. Fortunately, each hexagonal mirror segment is fully adjustable, and the impacted segment has already been adjusted to lessen some of the distortion.Arianespace's Ariane 5 rocket with NASAs James Webb Space Telescope onboard lifts up from the launchpad, at the Europes Spaceport, the Guiana Space Center in Kourou, French Guiana, on December 25, 2021. (Jody Amiet/AFP/Getty Images)1 hr 3 min agoScientists say new NASA images could change our perspective on the universe. Here's what to expect.From CNN's Ashley StricklandArtist conception of the James Webb Space Telescope. (Adriana Manrique Gutierrez/CIL/GSFC/NASA)We're about to have an entirely new perspective on the universe.The James Webb Space Telescope will release the rest of its first high-resolution color images on Tuesday. "We're only beginning to understand what Webb can and will do," said NASA Administrator Bill Nelson during a news conference in June."It's going to explore objects in the solar system and atmospheres of exoplanets orbiting other stars, giving us clues as to whether potentially their atmospheres are similar to our own."The space observatory, which launched in December, will be able to peer inside the atmospheres of exoplanets and observe some of the first galaxies created after the universe began by observing them through infrared light, which is invisible to the human eye.Webb began taking its first images a couple of weeks ago. The first packet of color images will be the result of 120 hours of observation, which is about five days' worth of data.The initial goal for the telescope was to see the first stars and galaxies of the universe, essentially watching "the universe turn the lights on for the first time," said Eric Smith, Webb program scientist and NASA Astrophysics Division chief scientist.What they will show: Klaus Pontoppidan, Webb project scientist at the Space Telescope Science Institute, said each image "will reveal different aspects of the universe in unprecedented detail and sensitivity." The images shared Tuesday will focus on four cosmic targets: the Carina Nebula, WASP-96b, the Southern Ring Nebula and Stephan's Quintet.They will show how galaxies interact and grow and how the collisions between galaxies drive star formation, as well as examples of the violent life cycle of stars. And we can expect to see the first spectrum of an exoplanet, or how wavelengths of light and different colors reveal characteristics of other worlds.The first release will highlight Webb's science capabilities as well as the ability of its massive golden mirror and science instruments to produce spectacular images.1 hr 13 min agoThese first images from the Webb telescope are just the beginning of the mission, scientists sayFrom CNN's Ashley StricklandNASA is releasing the first few images from the James Webb Space Telescope on Tuesday, but these initial pictures are just the beginning.The mission, originally expected to last for 10 years, has enough excess fuel capability to operate for 20 years, according to NASA Deputy Administrator Pam Melroy.The data collected by the space observatory will be publicly released so scientists around the world "can start a shared journey of discovery," Klaus Pontoppidan, Webb project scientist at the Space Telescope Science Institute, said.The data gathered by Webb will enable scientists to make precise measurements of planets, stars and galaxies in a way that has never been possible before, said Susan Mullally, Webb deputy project scientist at the Space Telescope Science Institute."Webb can see backwards in time just after the big bang by looking for galaxies that are so far away, the light has taken many billions of years to get from those galaxies to ourselves," said Jonathan Gardner, Webb deputy senior project scientist at NASA.Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate, has seen some of the first images that will be shared on Tuesday."It's an emotional moment when you see nature suddenly releasing some of its secrets," Zurbuchen said on Wednesday. "With this telescope, it's really hard not to break records."1 hr 19 min agoHow scientists are trying to protect the Webb telescope from being hit by micrometeoroidsFrom CNN's Ashley StricklandBall Aerospace optical technician Scott Murray inspects the first gold primary mirror segment, a critical element of NASA's James Webb Space Telescope, prior to cryogenic testing in the X-ray & Cryogenic Facility at NASA's Marshall Space Flight Center in Huntsville, Alabama. (David Higginbotham/MSFC/NASA)One of the 18 golden segments of the James Webb Space Telescope's giant mirror was hit by a micrometeoroid in May, according to an update from NASA. A micrometeoroid is a particle in space that is smaller than a grain of sand. Earth's atmosphere is hit by millions of meteoroids and micrometeoroids on a regular basis, but most are vaporized when they hit the atmosphere, according to NASA.But spacecraft don't have a protective bubble of atmosphere around them, so it's almost impossible to avoid these impacts.The team is continuing to analyze and assess what happened and how it may affect the telescope's performance. It's also likely the first of many such experiences that Webb will have over its time in space.When the telescope and its massive mirror were being built and tested on Earth, engineers made sure that the mirror could survive the micrometeoroid environment the spacecraft would experience in its orbit about a million miles from Earth at a point called L2, where dust particles are accelerated to extreme velocities.Webb was put through its paces while on Earth, and the team used both simulations and test impacts on mirror samples to understand what it would face. The May impact event was larger than anything the team tested or would have been able to model while Webb was still on the ground.Fortunately, each hexagonal mirror segment is fully adjustable, and the impacted segment has already been adjusted to lessen some of the distortion. This is something engineers can continue to do in the future as they monitor Webb's mirror for any signs of degradation in the space environment.Looking ahead: The Webb team will work closely with micrometeoroid prediction experts at NASA's Marshall Space Flight Center in Huntsville, Alabama. And Webb will be able to help NASA scientists learn more about the dust environment of the solar system at this orbit point, which can assist with preparing for future missions."With Webb's mirrors exposed to space, we expected that occasional micrometeoroid impacts would gracefully degrade telescope performance over time," said Lee Feinberg, Webb optical telescope element manager at NASA Goddard, in a statement."Since launch, we have had four smaller measurable micrometeoroid strikes that were consistent with expectations and this one more recently that is larger than our degradation predictions assumed. We will use this flight data to update our analysis of performance over time and also develop operational approaches to assure we maximize the imaging performance of Webb to the best extent possible for many years to come," Feinberg said.1 hr 25 min agoThese are the 5 cosmic targets captured in first Webb telescope imagesFrom CNN's Ashley StricklandThe Hubble Space Telescope captured this 50-light-year-wide view of the central region of the Carina Nebula. (NASA/ESA/N. Smith (UC, Berkeley)/Hubble Heritage Team (STScI/AURA)NASA is releasing the first images from its James Webb Space Telescope on Tuesday which will include a new look at four cosmic targets: the Carina Nebula, WASP-96b, the Southern Ring Nebula and Stephan's Quintet. A first image, shared Monday, showcased SMACS 0723.Located 7,600 light-years away, the Carina Nebula is a stellar nursery, where stars are born. It is one of the largest and brightest nebulae in the sky and home to many stars much more massive than our sun.Webb's study of the giant gas planet WASP-96b will be the first full-color spectrum of an exoplanet. The spectrum will include different wavelengths of light that could reveal new information about the planet, such as whether it has an atmosphere. Discovered in 2014, WASP-96b is located 1,150 light-years from Earth. It has half the mass of Jupiter and completes an orbit around its star every 3.4 days.The Southern Ring Nebula, also called the "Eight-Burst," is 2,000 light-years away from Earth. This large planetary nebula includes an expanding cloud of gas around a dying star.The space telescope's view of Stephan's Quintet will reveal the way galaxies interact with one another. This compact galaxy group, first discovered in 1787, is located 290 million light-years away in the constellation Pegasus. Four of the five galaxies in the group "are locked in a cosmic dance of repeated close encounters," according to a NASA statement.The image released Monday shows SMACS 0723, where a massive group of galaxy clusters act as a magnifying glass for the objects behind them. Called gravitational lensing, this will create Webb's first deep field view of incredibly old and distant, faint galaxies. It is "the deepest and sharpest infrared image of the distant universe to date," according to NASA.The targets were selected by an international committee, including members from NASA, the European Space Agency, the Canadian Space Agency and the Space Telescope Science Institute in Baltimore.1 hr 25 min agoHere's how the events will unfold todayFrom CNN's Ashley StricklandNASA is unveiling new photos from the James Webb Space Telescope on Tuesday. The first images from the telescope look deep into space as scientists explore stars, galaxies and exoplanets.Here's how the reveal will go:9:45 a.m. ET: NASA leadership and the Webb team will make opening remarks.10:30 a.m. ET: In a broadcast, the images will start to be released one by one.12:30 p.m. ET: Officials will hold a news conference and offer details about the images.NASA released the first image on Monday, capturing the deepest view of our universe ever to be seen by humans. NASA called the image "the deepest & sharpest infrared image of the early universe ever taken." Webb began taking its first images a couple of weeks ago. The first color images will be the result of 120 hours of observation, which is about five days' worth of data.
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Cosmology & The Universe
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Our view of the universe just expanded: The first image from NASA’s new space telescope unveiled Monday is brimming with galaxies and offers the deepest look of the cosmos ever captured.The first image from the $10 billion James Webb Space Telescope is the farthest humanity has ever seen in both time and distance, closer to the dawn of time and the edge of the universe. That image will be followed Tuesday by the release of four more galactic beauty shots from the telescope’s initial outward gazes.The “deep field” image released at a White House event is filled with lots of stars, with massive galaxies in the foreground and faint and extremely distant galaxies peeking through here and there. Part of the image is light from not too long after the Big Bang, which was 13.8 billion years ago.“We’re going to give humanity a new view of the cosmos,” NASA Administrator Bill Nelson told reporters last month in a briefing. “And it’s a view that we’ve never seen before.”President Biden and White House Office of Science and Technology Policy acting director Alondra Nelson met with NASA leaders to view the first image from the new Webb Space Telescope on Monday.Chip Somodevilla/GettyThe images on tap for Tuesday include a view of a giant gaseous planet outside our solar system, two images of a nebula where stars are born and die in spectacular beauty and an update of a classic image of five tightly clustered galaxies that dance around each other.The world’s biggest and most powerful space telescope rocketed away last December from French Guiana in South America. It reached its lookout point 1 million miles (1.6 million kilometers) from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool.The plan is to use the telescope to peer back so far that scientists will get a glimpse of the early days of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus.Webb is considered the successor to the highly successful, but aging Hubble Space Telescope. Hubble has stared as far back as 13.4 billion years. It found the light wave signature of an extremely bright galaxy in 2016. Astronomers measure how far back they look in light-years with one light-year being 5.8 trillion miles (9.3 trillion kilometers).“Webb can see backwards in time to just after the Big Bang by looking for galaxies that are so far away that the light has taken many billions of years to get from those galaxies to our telescopes,” said Jonathan Gardner, Webb’s deputy project scientist said during the media briefing.How far back did that first image look? Over the next few days, astronomers will do intricate calculations to figure out just how old those galaxies are, project scientist Klaus Pontoppidan said last month.The deepest view of the cosmos “is not a record that will stand for very long,” Pontoppidan said, since scientists are expected to use the telescope to go even deeper.Vice President Kamala Harris and NASA Administrator Bill Nelson joined a briefing to review the first images transmitted back to earth from the Webb telescope.Chip Somodevilla/GettyThomas Zurbuchen, NASA’s science mission chief said when he saw the images he got emotional and so did his colleagues: “It’s really hard to not look at the universe in new light and not just have a moment that is deeply personal.”At 21 feet (6.4 meters), Webb’s gold-plated, flower-shaped mirror is the biggest and most sensitive ever sent into space. It’s comprised of 18 segments, one of which was smacked by a bigger than anticipated micrometeoroid in May. Four previous micrometeoroid strikes to the mirror were smaller. Despite the impacts, the telescope has continued to exceed mission requirements, with barely any data loss, according to NASA.NASA is collaborating on Webb with the European and Canadian space agencies.“I’m now really excited as this dramatic progress augurs well for reaching the ultimate prize for many astronomers like myself: pinpointing “Cosmic Dawn” — the moment when the universe was first bathed in starlight,” Richard Ellis, professor of astrophysics at University College London, said via email.___AP Aerospace Writer Marcia Dunn contributed.___The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
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Cosmology & The Universe
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Whether extraterrestrial life exists or whether intelligent extraterrestrial life exists aren't the same question. Finding the former is, of course, more likely than finding the latter. We are simultaneously looking for both, but both require an entirely different approach. When it comes to the search for extraterrestrial intelligence, SETI (which literally stands for Search for ExtraTerrestrial Intelligence) contains a comprehensive variety of efforts.During the early beginnings in the late 1800s, we first started looking for signs of extraterrestrial intelligence within our own solar system. In modern times, however, most of the global effort goes to monitoring electromagnetic radiation to detect potential transmissions. A more recent niche avenue in the search takes aim at technosignatures (where scientists look for signs of megastructures like space mirrors and Dyson spheres). At the very cutting edge in the search, we find interstellar quantum communications. Scientists have only recently started thinking of concrete ways of how to search for this kind of transmission.But if we are to actually discover extraterrestrial life, what do scientists expect to find? According to cosmologist Martin Rees, we aren't likely to find the classic aliens as commonly portrayed in sci-fi movies; he thinks it is far likely that we will stumble upon something else. In this article, Rees explains why he expects that the bulk of civilizations out there would probably be artificial. Enjoy!By Martin Rees - Emeritus Professor of Cosmology and Astrophysics, University of Cambridge Is there intelligent life elsewhere in the universe? It’s a question that has been debated for centuries, if not millenia. But it is only recently that we’ve had an actual chance of finding out, with initiatives such as SETI using radio telescopes to actively listen for radio messages from alien civilizations.What should we expect to detect if these searches succeed? My suspicion is that it is very unlikely to be little green men – something I speculated about at a talk at a Breakthrough Listen (a SETI project) conference.Suppose there are other planets where life began and that it followed something like a Darwinian evolution (which needen’t be the case). Even then, it’s highly unlikely that the progression of intelligence and technology would happen at exactly the same pace as on Earth. If it lagged significantly behind, then that planet would plainly reveal no evidence of extraterrestrial life to our radio telescopes. But around a star older than the Sun, life could have had a head start of a billion years or more.Human technological civilization only dates back millennia (at most) – and it may be only one or two more centuries before humans, made up of organic materials such as carbon, are overtaken or transcended by inorganic intelligence, such as AI. Computer processing power is already increasing exponentially, meaning AI in the future may be able to use vastly more data than it does today. It seems to follow that it could then get exponentially smarter, surpassing human general intelligence.Perhaps a starting point would be to enhance ourselves with genetic modification in combination with technology – creating cyborgs with partly organic and partly inorganic parts. This could be a transition to fully artificial intelligences.AI may even be able to evolve, creating better and better versions of itself on a faster-than-Darwinian timescale for billions of years. Organic human-level intelligence would then be just a brief interlude in our “human history” before the machines take over. So if alien intelligence had evolved similarly, we’d be most unlikely to “catch” it in the brief sliver of time when it was still embodied in biological form. If we were to detect extraterrestrial life, it would be far more likely to be electronic than flesh and blood – and it may not even reside on planets.We must therefore reinterpret the Drake equation, which was established in 1960 to estimate the number of civilizations in the Milky Way with which we could potentially communicate. The equation includes various assumptions, such as how many planets there are, but also how long a civilization is able to release signals into space, estimated to be between 1,000 and 100 million years.But the lifetime of an organic civilization may be millennia at most, while its electronic diaspora could continue for billions of years. If we include this in the equation, it seems there may be more civilizations out there than we thought, but that the majority of them would be artificial.We may even want to rethink the term “alien civilizations”. A “civilization” connotes a society of individuals. In contrast, extraterrestrials might be a single integrated intelligence.Decoding messagesIf SETI succeeded, it would therefore be unlikely to record decodable messages. Instead, it may spot a byproduct (or even a malfunction) of some super complex machine far beyond our comprehension.SETI focuses on the radio part of the electromagnetic spectrum. But as we have no idea of what’s out there, we should clearly explore all wavebands, including the optical and X-ray parts. Rather than just listening for radio transmission, we should also be alert to other evidence of non-natural phenomena or activity. These include artificial structures built around stars to absorb their energy (Dyson spheres) or artificially created molecules, such as chlorofluorocarbons – nontoxic, nonflammable chemicals containing carbon, chlorine, and fluorine – in planet atmospheres. These chemicals are greenhouse gasses that can’t be created by natural processes, meaning they could be a sign of “terraforming” (changing a planet to make it more habitable) or industrial pollution. I’d argue it would even be worth looking for traces of aliens in our own solar system. While we can probably rule out visits by human-like species, there are other possibilities. An extraterrestrial civilisation that had mastered nanotechnology may have transferred its intelligence to tiny machines, for example. It could then invade other worlds, or even asteroid belts, with swarms of microscopic probes.And even if we did receive a decodable radio message, how could we know what the intention of the super-intelligent sender would be? We have absolutely zero idea – think of the variety of bizarre motives (ideological, financial and religious) that have driven human endeavors in the past. They may be peaceful and inquisitive. Even less obtrusively, they may realize that it’s easier to think at low temperatures – getting far away from any star, or even hibernating for billions of years until it’s cooler. But they could be expansionist – and this seems the expectation of most who’ve thought about the future trajectory of civilizations.The future of intelligenceAs the universe evolves, intelligent species may get unfathomably clever. Just take our own future. Eventually, stellar births and deaths in our galaxy will proceed gradually more slowly, until it gets jolted as the Milky Way crashes with the Andromeda galaxy in about billion years. The debris of our galaxy, Andromeda and their smaller companions within our local group of galaxies will thereafter clump together into one amorphous galaxy, while distant ones move away from us and eventually disappear.But our remnant will continue for far longer – time enough, perhaps, for a civilization to emerge that could be in possession of huge amounts of energy, even harnessing the entire mass of a galaxy.This may be the culmination of the long-term trend for living systems to gain complexity. At this stage, all the atoms that were once in stars and gas could be transformed into a giant organism of galactic scale. Some science fiction authors envisage stellar-scale engineering to create black holes and wormholes – bridges connecting different points in spacetime, in theory providing shortcuts for space travelers. These concepts are far beyond any technological capability that we can envisage, but not in violation of basic physical laws.Are we artificial?Post-human intelligences may also be able to build computers with enormous processing power. Humans are already able to model some quite complex phenomenon, such as the climate. More intelligent civilizations, however, may be able to simulate living things – with actual consciousnesses – or even entire worlds or universes. How do we know that we aren’t living in such a simulation created by technologically superior aliens? Maybe we are no more than a bit of entertainment for some supreme being who is running such a model? Indeed, if life is destined to be able to create technologically advanced civilisations that can make computer programs, there may be more simulated universes our there than real ones out there – making it conceivable that we are in one of them.This conjecture may sound outlandish, but it is all based on our current understanding of physics and cosmology. We should, however, surely be open-minded about the possibility that there’s much we don’t understand. Perhaps the laws we see and the constants we measure are only “local” and differ in other parts of the universe? That would lead to even more jaw-dropping possibilities.Ultimately, physical reality could encompass complexities that neither our intellect nor our senses can grasp. Some electronic “brains” may simply have a quite different perception of reality. Nor can we predict or understand their motives. That’s why we can’t assess whether the current radio silence that Seti are experiencing signifies the absence of advanced alien civilisations, or simply their preference.*This article is partly adapted from a speech given by the author at a Breakthrough Listen conference in 2018*Banner Image Credit: cbpix via Shutterstock / HDR tune by Universal-SciSources and further reading:The ConversationSearching for Interstellar Quantum Communications - (The Astronomical Journal)The SETI InstituteWhy the idea of alien life now seems inevitable and possibly imminent - (Universal-Sci)Putting unfathomable astronomical distances into human perspective - (Universal-Sci)
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Cosmology & The Universe
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The case for a small universe
The universe is big, as Douglas Adams would say.
The most distant light we can see is the cosmic microwave background (CMB), which has taken more than 13 billion years to reach us. This marks the edge of the observable universe, and while you might think that means the universe is 26 billion light-years across, thanks to cosmic expansion it is now closer to 46 billion light-years across. By any measure, this is pretty darn big. But most cosmologists think the universe is much larger than our observable corner of it. That what we can see is a small part of an unimaginably vast, if not infinite creation. However, a new paper published on the arXiv preprint server argues that the observable universe is mostly all there is.
In other words, on a cosmic scale, the universe is quite small.
There are several reasons why cosmologists think the universe is large. One is the distribution of galaxy clusters. If the universe didn't extend beyond what we see, the most distant galaxies would feel a gravitational pull toward our region of the cosmos, but not away from us, leading to asymmetrical clustering. Since galaxies cluster at around the same scale throughout the visible universe. In other words, the observable universe is homogenous and isotropic.
A second point is that spacetime is flat. If spacetime weren't flat, our view of distant galaxies would be distorted, making them appear much larger or smaller than they actually are. Distant galaxies do appear slightly larger due to cosmic expansion, but not in a way that implies an overall curvature to spacetime. Based on the limits of our observations, the flatness of the cosmos implies it is at least 400 times larger than the observable universe.
Then there is the fact that the cosmic microwave background is almost a perfect blackbody. There are small fluctuations in its temperature, but it is much more uniform than it should be. To account for this, astronomers have proposed a period of tremendous expansion just after the Big Bang, known as early cosmic inflation. We have not observed any direct evidence of it, but the model solves so many cosmological problems that it's widely accepted. If the model is accurate, then the universe is on the order of 1026 times larger than the observable universe.
So given all of this theoretical and observational evidence, how could anyone argue that the universe is small? It has to do with string theory and the swamplands.
Although string theory is often presented as a physical theory, it's actually a collection of mathematical methods. It can be used in the development of complex physical models, but it can also just be mathematics for its own sake. One of the problems with connecting the mathematics of string theory to physical models is that the effects would only be seen in the most extreme situations, and we don't have enough observational data to rule out various models. However, some string theory models appear much more promising than others. For example, some models are compatible with quantum gravity, and others are not. So often theorists will define a "swampland" of theories that aren't promising.
When you separate the promising theoretical lands from the swamp, what you are left with are theories where early cosmic inflation isn't an option. Most of the inflationary string theory models are in the swampland. This leads one to ask whether you could construct a model cosmology that matches observation without early inflation. Which brings us to this new study.
One way to get around early cosmic inflation is to look at higher-dimensional structures. Classic general relativity relies upon four physical dimensions, three of space and one of time, or 3+1. Mathematically you could imagine a 3+2 universe or 4+1, where the global structure can be embedded into an effective 3+1 structure. This is a common approach in string theory since it isn't limited to the standard structure of general relativity.
The authors demonstrate that under just the right conditions, you could construct a higher-dimensional structure within string theory that matches observation and avoids the swampland. Based on their toy models, the universe may only be a hundred or a thousand times larger than the observed universe. Still big, but downright tiny when compared to the early inflation models.
All of this is pretty speculative, but in a way so is early cosmic inflation. If early cosmic inflation is true, we should be able to observe its effect through gravitational waves in the somewhat near future. If that fails, it might be worth looking more closely at string theory models that keep us out of the theoretical swamp.
More information: Jean-Luc Lehners et al, A small Universe, arXiv (2023). DOI: 10.48550/arxiv.2309.03272
Journal information: arXiv
Provided by Universe Today
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Cosmology & The Universe
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Celestial phenomena that change with time such as exploding stars, mysterious objects that suddenly brighten and variable stars are a new frontier in astronomical research, with telescopes that can rapidly survey the sky revealing thousands of these objects.
The largest data release of relatively nearby supernovae (colossal explosions of stars), containing three years of data from the University of Hawaiʻi Institute for Astronomy's (IfA) Pan-STARRS telescope atop Haleakalā on Maui, is publicly available via the Young Supernova Experiment (YSE). The project, which began in 2019, surveyed more than 1,500 square degrees of sky every three days, and discovered thousands of new cosmic explosions and other astrophysical transients, dozens of them just days or hours after exploding.
The newly-released data contains information on nearly 2,000 supernovae and other luminous variable objects with observations in multiple colors. It is also the first to extensively use the multi-color imaging to classify the supernovae and estimate their distances.
Astrophysicists use large imaging surveys -- systematic studies of large areas of the sky over time -- and different parts of the electromagnetic spectrum for many scientific goals. Some are used to study distant galaxies and how they evolve over cosmic time, or look at specific regions of the sky that are especially important, such as the Andromeda Galaxy.
"Pan-STARRS produces a steady stream of transient discoveries, observing large areas of the sky every clear night with two telescopes," said Mark Huber, a senior researcher at IfA. "With over a decade of observations, Pan-STARRS operates one of the best calibrated systems in astronomy, with a detailed reference image of the static sky visible from Haleakalā. This enables rapid discovery and follow-up of supernovae and other transient events, well suited for programs like YSE to build up the sample required for analysis and this significant data release."
YSE is designed to find energetic astrophysical "transient" sources such as supernovae, tidal disruption events and kilonovae (extremely energetic explosions). These transients evolve quickly, rising to their maximum brightness and then fading away after a few days or months.
Multi-institution collaboration
The images from Pan-STARRS are transferred to UH's Information Technology Center for initial processing and scientific calibration by the Pan-STARRS Image Processing Pipeline. Higher-level processing, detailed analysis and storage was then performed using computing systems at the National Center for Supercomputing Applications' (NCSA) Center for Astrophysical Surveys (CAPS), the University of California, Santa Cruz (UCSC), and the Dark Cosmology Centre (DARK) at the Niels Bohr Institute at the University of Copenhagen.
The survey and the tools used to analyze the data are critical precursors to the upcoming Vera C. Rubin Observatory Legacy Survey of Space and Time, a new 8.4-meter telescope being built in Chile. Rubin Observatory will survey the entire sky every three nights, discovering so many variable and exploding objects that it will be impossible to obtain detailed follow-up observations. The ability to classify these objects from the survey data alone will be vital to choosing the most interesting ones for astronomers to target with other telescopes.
Gautham Narayan, deputy director of CAPS, is leading the cosmological analysis for the data sample and former CAPS graduate fellow Patrick Aleo is lead author of the paper, "The Young Supernova Experiment Data Release 1 (YSE DR1): Light Curves and Photometric Classification of 1975 Supernovae."
"Much of the time-domain universe is uncharted. We still do not know the progenitor systems of many of the most common classes of transients, such as type Ia supernovae, while still using these sources to try and understand the expansion history of our universe," Narayan said. "We've also seen one electromagnetic counterpart to a binary neutron star merger. There are many kinds of transients that are theoretically predicted, but have never been seen at all."
Ken Chambers, Pan-STARRS director, added that "this collaboration with the Young Supernova Experiment makes exceptional use of Pan-STARRS' ability to routinely survey the sky for transient phenomena and moving objects. We have provided an unprecedented sample of young supernovae discovered before their peak luminosity that will be an important resource for supernova researchers and cosmologists for many years. Looking ahead, Pan-STARRS will remain a crucial resource in the Northern Hemisphere to complement the Rubin Observatory in the Southern Hemisphere."
This groundbreaking effort is a collaboration between UH, UCSC, DARK, NCSA and University of Illinois -- Urbana-Champaign (UIUC) and the University of Hawaiʻi. The collaboration used Hawaiʻi's Pan-STARRS1 telescope and data pipeline to collect and process the images, DARK's analysis of the data on its computing cluster, UCSC's organization of the survey and data hosting, and NCSA and UIUC's analysis.
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Cosmology & The Universe
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The James Webb Space Telescope (JWST) may have found evidence of a strange and elusive type of star that only existed in the very early universe, when invisible dark matter was one of the only available fuel sources.
New research suggests that three of the earliest objects identified as galaxies by the JWST aren't galaxies at all, but rather "dark stars" — immense, ultrabright hypothetical objects that are powered by dark matter rather than nuclear fusion. If the theory is correct, then this could finally help scientists better understand dark matter, the universe's most mysterious component.
"These things are atomic matter that is powered by dark matter, and one supermassive dark star could be as bright as an entire galaxy containing normal fusion-powered stars," astrophysicist Katherine Freese, an astrophysicist at the University of Texas at Austin and lead author of a new study published July 11 in the journal Proceedings of the National Academy of Sciences, told Live Science.
Explosive annihilation
According to theory, dark stars are enormous in comparison to "ordinary" stars that exist in the universe today, like the sun. Dark stars are hypothesized to have widths hundreds of times greater than the sun's. These stars, composed mostly of hydrogen and some helium, existed in protogalaxies when the universe contained mostly those two elements; heavier elements hadn't yet been forged by nuclear fusion in stars. However, about one thousandth of a dark star’s mass would be made of a secret fuel source — dark matter.
Dark matter, which is all but invisible because it doesn't interact with light, makes up an estimated 85% of the matter in the universe. Theory suggests that when two dark matter particles collide, they may "annihilate" each other, turning their combined mass into a shower of energetic gamma-ray radiation.
"If dark matter is self-annihilating, then the annihilation products could get stuck inside this hydrogen cloud,” that makes up dark stars, Freese said. “And what that means is you're taking all of the energy that used to be in the mass of the dark matter and dumping it into this cloud," Feese said.
Freese added that while "everyday" stars depend on high temperatures, dark matter annihilation could occur at any temperature.
"Dark matter annihilation doesn't care about the temperature," Freese said. "So you have dark matter annihilation throughout the entire [width] of the dark star. And the surface temperature is relatively cool. Because of that, there's no ionizing photons or other stuff coming off preventing the accretion of more matter."
In contrast, when normal stars have acquired enough mass to start nuclear fusion, the radiation that they pump out pushes away the gas envelope that surrounds them, preventing them from accreting more matter and thus growing further.
This means that, while dark stars may start out with a mass about the same as the sun, the objects can accrete more and more matter, growing to be a million times as massive as the sun, and a billion times as bright, Freese added.
Dark star, or ancient galaxy?
Given their huge size, dark stars would appear as more spread-out objects rather than as point-like objects, like modern-day stars. This is how three ancient objects detected by the JWST — namedJADES-GS-z13–0, JADES-GS-z12–0, and JADES-GS-z11–0 — could have been misidentified as galaxies, according to the new research. These candidate dark stars date to between 320 million and to 420 million years after the Big Bang.
But, the dark matter annihilation process can't continue forever. Dark stars sit in the dark-matter-rich centers of protogalaxies, which merge together continuously to form proper galaxies, and eventually, this moves dark stars away from their dark matter fuel.
"As dark stars get displaced from the dark-matter-rich center, the dark stars start collapsing," Freese explained. "This will trigger fusion in the smaller ones, creating ordinary fusion-powered stars [which are all created from collapsing clouds of gas]. The bigger ones will collapse immediately into black holes."
This means that dark stars don't exist in the universe today, Freese added. However, it’s difficult to pinpoint exactly when in the 13.8-billion-year history of the universe that dark stars would have ceased to be.
Confirming the existence of dark stars via these JWST observations would be huge, but Freese pointed out that she and the team aren't quite there yet. This confirmation would require either looking at these candidate dark stars for much longer to build a more complete picture of their light output, or waiting for magnified observations that better reveal the light emissions of these objects, which could allow scientists to identify whether the objects have pure hydrogen and helium compositions, as would be expected from dark stars.
"The dark star idea has been hanging in there for many years, and it would be extremely exciting to me to have this proven correct," Freese concluded.
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Robert Lea is a science journalist in the U.K. who specializes in science, space, physics, astronomy, astrophysics, cosmology, quantum mechanics and technology. Rob's articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University
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Cosmology & The Universe
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Stars beam brightly out of the darkness of space thanks to fusion, atoms melding together and releasing energy. But what if there’s another way to power a star?
A team of three astrophysicists — Katherine Freese at The University of Texas at Austin, in collaboration with Cosmin Ilie and Jillian Paulin ’23 at Colgate University — analyzed images from the James Webb Space Telescope (JWST) and found three bright objects that might be “dark stars,” theoretical objects much bigger and brighter than our sun, powered by particles of dark matter annihilating. If confirmed, dark stars could reveal the nature of dark matter, one of the deepest unsolved problems in all of physics.
“Discovering a new type of star is pretty interesting all by itself, but discovering it’s dark matter that’s powering this—that would be huge,” said Freese, director of the Weinberg Institute for Theoretical Physics and the Jeff and Gail Kodosky Endowed Chair in Physics at UT Austin.
Although dark matter makes up about 25% of the universe, its nature has eluded scientists. Scientists believe it consists of a new type of elementary particle, and the hunt to detect such particles is on. Among the leading candidates are Weakly Interacting Massive Particles. When they collide, these particles annihilate themselves, depositing heat into collapsing clouds of hydrogen and converting them into brightly shining dark stars. The identification of supermassive dark stars would open up the possibility of learning about the dark matter based on their observed properties.
The research is published in the Proceedings of the National Academy of Sciences.
Follow-up observations from JWST of the objects’ spectroscopic properties — including dips or excess of light intensity in certain frequency bands — could help confirm whether these candidate objects are indeed dark stars.
Confirming the existence of dark stars might also help solve a problem created by JWST: There seem to be too many large galaxies too early in the universe to fit the predictions of the standard model of cosmology.
“It’s more likely that something within the standard model needs tuning, because proposing something entirely new, as we did, is always less probable,” Freese said. “But if some of these objects that look like early galaxies are actually dark stars, the simulations of galaxy formation agree better with observations.”
The three candidate dark stars (JADES-GS-z13-0, JADES-GS-z12-0, and JADES-GS-z11-0) were originally identified as galaxies in December 2022 by the JWST Advanced Deep Extragalactic Survey (JADES). Using spectroscopic analysis, the JADES team confirmed the objects were observed at times ranging from about 320 million to 400 million years after the Big Bang, making them some of the earliest objects ever seen.
“When we look at the James Webb data, there are two competing possibilities for these objects,” Freese said. “One is that they are galaxies containing millions of ordinary, population-III stars. The other is that they are dark stars. And believe it or not, one dark star has enough light to compete with an entire galaxy of stars.”
Dark stars could theoretically grow to be several million times the mass of our sun and up to 10 billion times as bright as the sun.
“We predicted back in 2012 that supermassive dark stars could be observed with JWST,” said Ilie, assistant professor of physics and astronomy at Colgate University. “As shown in our recently published PNAS article, we already found three supermassive dark star candidates when analyzing the JWST data for the four high redshift JADES objects spectroscopically confirmed by Curtis-Lake et al, and I am confident we will soon identify many more.”
The idea for dark stars originated in a series of conversations between Freese and Doug Spolyar, at the time a graduate student at the University of California, Santa Cruz. They wondered: What does dark matter do to the first stars to form in the universe? Then they reached out to Paolo Gondolo, an astrophysicist at the University of Utah, who joined the team. After several years of development, they published their first paper on this theory in the journal Physical Review Letters in 2008.
Together, Freese, Spolyar and Gondolo developed a model that goes something like this: At the centers of early protogalaxies, there would be very dense clumps of dark matter, along with clouds of hydrogen and helium gas. As the gas cooled, it would collapse and pull in dark matter along with it. As the density increased, the dark matter particles would increasingly annihilate, adding more and more heat, which would prevent the gas from collapsing all the way down to a dense enough core to support fusion as in an ordinary star. Instead, it would continue to gather more gas and dark matter, becoming big, puffy and much brighter than ordinary stars. Unlike ordinary stars, the power source would be evenly spread out, rather than concentrated in the core. With enough dark matter, dark stars could grow to be several million times the mass of our sun and up to 10 billion times as bright as the sun.
Funding for this research was provided by the U.S. Department of Energy’s Office of High Energy Physics program and the Vetenskapsradet (Swedish Research Council) at the Oskar Klein Centre for Cosmoparticle Physics at Stockholm University.
Journal
Proceedings of the National Academy of Sciences
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Supermassive Dark Star candidates seen by JWST
Article Publication Date
11-Jul-2023
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Cosmology & The Universe
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Listening to the radio on the far side of the moon
There are unexplored regions of the universe—and there are also unexplored times. In fact, there's a nearly 400-million-year gap in our universe's history that we've never seen: a time before stars known as the Dark Ages. To investigate that era, researchers want to pick up a particular radio signal that can't be measured from Earth.
The first step to listening for it is a pathfinder project known as the Lunar Surface Electromagnetics Experiment-Night, or LuSEE-Night. The experiment is slated to head to the moon in 2025, where it will test technology in the harsh lunar environment.
The project is a collaboration between NASA and the Department of Energy, with partners from Lawrence Berkeley National Laboratory (Berkeley Lab), Brookhaven National Laboratory (lead DOE lab), UC Berkeley, and the University of Minnesota. The Berkeley Lab team has started building the experiment's antenna that will try to tune in to those ancient radio waves.
"If you're on the far side of the moon, you have a pristine, radio-quiet environment from which you can try to detect this signal from the Dark Ages," said Kaja Rotermund, a postdoctoral researcher at Berkeley Lab who is working on the antenna. "LuSEE-Night is a mission showing whether we can make these kinds of observations from a location that we've never been in, and also for a frequency range that we've never been able to observe."
The Dark Ages signal can't be measured from the Earth because our atmosphere absorbs, refracts, and reflects the radio signal before it ever reaches instruments on the ground. Even if it could, the radio signal would be drowned out by noise from our own electronics and communications.
The moon acts as a shield, blocking out radio waves from Earth. And by gathering data only during the two-week lunar night, the experiment can also block out radio waves from the sun. But this isolated spot also brings challenges. LuSEE-Night must operate in temperatures around -280 degrees Fahrenheit, then weather an extreme swing to 250 degrees Fahrenheit during lunar day, when it will recharge its batteries.
And because the far side of the moon never faces Earth, direct communication with the experiment is impossible. LuSEE-Night will have to send all its data through a relay satellite that passes overhead.
"The engineering to land a scientific instrument on the far side of the moon alone is a huge accomplishment," said Aritoki Suzuki, who leads the antenna project for Berkeley Lab. "If we can demonstrate that this is possible—that we can get there, deploy, and survive the night—that can open up the field for the community and future experiments."
Rocking out to the dark ages
After the big bang, the universe was filled with a hot, opaque plasma of roaming particles. After about 400,000 years, the plasma had cooled enough for protons and electrons to combine into hydrogen, freeing light to travel through the universe. That light, known as the cosmic microwave background or CMB, reached our telescopes and gave us a baby picture of our universe. After that, hydrogen gas dominated for nearly 400 million years during the Dark Ages, until the first stars and galaxies began to form at the cosmic dawn.
"With the CMB, we have this snapshot of the early universe. And we also have images from the more recent universe, once the stars are born," Suzuki said. "We want to study the Dark Ages period because it connects how the early universe evolved into the universe we see today."
Researchers expect that the hydrogen absorbed some of the energy from the CMB at a particular frequency. As the universe expanded, the frequency shifted lower and might now be picked up as radio waves. LuSEE-Night will listen for frequencies between 0.5 and 50 megahertz, though it's likely that future, more sensitive experiments will be needed to find the faint signal.
"We're looking for this very tiny dip that is potentially the Dark Ages signal," Rotermund said. "We can learn a lot about the cosmology that's being governed during this time period in a way that is unaffected by stars and other objects that grow very differently, compared to the universe in general."
From the lab to the moon
To collect radio waves, LuSEE-Night will use two pairs of antennas that are six meters from tip to tip—but the whole experiment must travel to the moon in a cube with one-meter sides. Once LuSEE-Night lands, the spring-loaded "stacer" antennas will uncoil into position.
To make the antenna system for its lunar voyage, Berkeley Lab researchers began with simulations and models and then turned to building and testing.
The team headed to the roof of one of Berkeley Lab's buildings with a scale model of one antenna, reduced from 3 meters to 30 centimeters. They used a transmitter to send signals to the antenna across the wide-open space.
"It's important to characterize our antennas so we're confident in the information that we're getting, and so that we set it up in a way that has the best chance of seeing the Dark Ages signal," Rotermund said. The team has figured out the best design, simulated what the antennas' beam patterns will look like, and calibrated the electronics so they can tell how strong a signal they are receiving.
The Berkeley Lab team is also building a turntable that will periodically rotate the antennas. Because researchers expect the Dark Ages signal to be the same in all directions, any signal that changes after the spin can essentially be filtered from the data. That includes radio noise from other planets or galaxies, or even variations caused by the rocky surface (the "lunar regolith") underneath the experiment.
Following a successful technical review in summer, the team is now working with UC Berkeley's Space Science Laboratory and building the flight model that will head to the moon. They'll deliver the final antenna subsystem by January 2024, where it will be integrated with LuSEE-Night's other components—including the whopping 110-pound (50-kg) battery that sustains it through the night. The experiment will head to the moon on a future Commercial Lunar Payload Services (CLPS) flight operated by Firefly Aerospace and collect data for 18 months.
Provided by Lawrence Berkeley National Laboratory
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Cosmology & The Universe
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Vast bubble of galaxies discovered, given Hawaiian name
A University of Hawaiʻi-led discovery of an immense bubble 820 million light years from Earth is believed to be a fossil-like remnant of the birth of the universe. Astronomer Brent Tully from the UH Institute for Astronomy and his team unexpectedly found the bubble within a web of galaxies. The entity has been given the name Hoʻoleilana, a term drawn from the Kumulipo, a Hawaiian creation chant evoking the origin of structure.
The new findings, published in The Astrophysical Journal, mention that these massive structures are predicted by the Big Bang theory, as the result of 3D ripples found in the material of the early universe, known as Baryon Acoustic Oscillations (BAO).
"We were not looking for it. It is so huge that it spills to the edges of the sector of the sky that we were analyzing," explained Tully. "As an enhancement in the density of galaxies it is a much stronger feature than expected. The very large diameter of one billion light years is beyond theoretical expectations. If its formation and evolution are in accordance with theory, this BAO is closer than anticipated, implying a high value for the expansion rate of the universe."
Astronomers located the bubble using data from Cosmicflows-4, which is to date, the largest compilation of precise distances to galaxies. Tully co-published the exceptional catalog in fall 2022. His team of researchers believe this may be the first time astronomers identified an individual structure associated with a BAO. The discovery could help bolster scientists' knowledge of the effects of galaxy evolution.
Enormous bubbles of matter
In the well-established Big Bang theory, during the first 400,000 years, the universe is a cauldron of hot plasma similar to the interior of the sun. Within a plasma, electrons were separated from the atomic nuclei. During this period, regions with slightly higher density began to collapse under gravity, even as the intense bath of radiation attempted to push matter apart. This struggle between gravity and radiation made the plasma oscillate or ripple and spread outward.
The largest ripples in the early universe depended on the distance a sound wave could travel. Set by the speed of sound in the plasma, this distance was almost 500 million light years, and was fixed once the universe cooled and stopped being a plasma, leaving vast three-dimensional ripples. Throughout the eons, galaxies formed at the density peaks, in enormous bubble-like structures. Patterns in the distribution of galaxies, properly discerned, could reveal the properties of these ancient messengers.
"I am the cartographer of the group, and mapping Hoʻoleilana in three dimensions helps us understand its content and relationship with its surroundings," said researcher Daniel Pomarede of CEA Paris-Saclay University in France. "It was an amazing process to construct this map and see how the giant shell structure of Hoʻoleilana is composed of elements that were identified in the past as being themselves some of the largest structures of the universe."
This same team of researchers also identified the Laniākea Supercluster in 2014. That structure, which includes the Milky Way, is small in comparison. Stretching at a diameter of about 500 million light years, Laniākea extends to the near edge of this much larger bubble.
Uncovering a single BAO
Tully's team discovered that Hoʻoleilana had been noted in a 2016 research paper as the most prominent of several shell-like structures seen in the Sloan Digital Sky Survey. However, the earlier work did not reveal the full extent of the structure, and that team did not conclude they had found a BAO.
Using the Cosmicflows-4 catalog, the researchers were able to see a full spherical shell of galaxies, identify its center, and show that there is a statistical enhancement in the density of galaxies in all directions from that center. Hoʻoleilana encompasses many well-known structures previously found by astronomers, such as the Harvard/Smithsonian Great Wall containing the Coma Cluster, the Hercules Cluster and the Sloan Great Wall. The Boötes Supercluster resides at its center. The historic Boötes Void, a massive empty spherical region, lies inside Hoʻoleilana.
The implications of Hoʻoleilana
Tests with simulations have demonstrated that the shell structure identified as Hoʻoleilana has less than 1% probability of being a statistical accident. Hoʻoleilana has the properties of a theoretically anticipated baryon acoustic oscillation, including the prominence at its center of a rich supercluster; however, it stands out stronger than expected.
In detail, Hoʻoleilana is slightly larger than anticipated from the theory of the standard model of cosmology, and what has been found from prior statistical pair-wise studies of galaxy separations. The size is in accord with observations of the local expansion rate of the universe and of galaxy flows on large scales that also hint at subtle problems with the standard model.
More information: R. Brent Tully et al, Ho'oleilana: An Individual Baryon Acoustic Oscillation?, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/aceaf3
R. Brent Tully et al, Cosmicflows-4, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/ac94d8
Journal information: Astrophysical Journal
Provided by University of Hawaii at Manoa
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Cosmology & The Universe
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Recent debates around the testability of the inflationary paradigm raise the question of how to model-independently discriminate it from competing scenarios. We argue that a detection of the cosmic graviton background (CGB), the relic radiation from gravitons decoupling around Planck time, would rule out the inflationary paradigm, as realistic inflationary models would dilute the CGB to an unobservable level. The CGB contribution to the effective number of relativistic species, ΔNeff,g ≈ 0.054, is well within the reach of next-generation cosmological probes. We argue that detecting the high-frequency stochastic gravitational wave background associated to the CGB will be challenging but potentially feasible. We briefly discuss expectations within alternatives to inflation, focusing on bouncing cosmologies and emergent scenarios.Inflation, a postulated stage of quasi-de Sitter expansion in the primordial universe, is widely regarded as the leading paradigm for the very early universe. Originally introduced to address various fine-tuning problems of the hot big bang (hBB) model, inflation provides a compelling mechanism for generating the density perturbations from which structure eventually originated (Starobinsky 1980; Guth 1981; Mukhanov & Chibisov 1981; Albrecht & Steinhardt 1982; Linde 1982). The predictions of some of the simplest inflationary models are in remarkable agreement with observations of the cosmic microwave background (CMB) and the large-scale structure (LSS), which in turn is commonly viewed as a sign of the inflationary paradigm's success.Despite these successes, inflation is not free of open issues, and over the years criticisms have been raised about its status (see, e.g., Ijjas et al. 2014; Martin 2019). One of the major bones of contention is driven by the large flexibility with regards to the predictions of individual inflationary models, and concerns whether or not the inflationary paradigm is falsifiable. We use the term "paradigm" and not "model" since any given inflationary model is clearly falsifiable, whereas these doubts concern the inflationary scenario as a whole. Here we do not seek to take sides in the debate, but simply note that these issues strongly motivate the question of how to model-independently discriminate the inflationary paradigm from alternative scenarios for the production of density perturbations.We address the above question by identifying a signature de facto precluded to any realistic inflationary model, and whose observation would thus rule out the inflationary paradigm. The decoupling of primordial gravitons around Planck time should leave behind a thermal background of relic gravitons: the cosmic graviton background (CGB). An inflationary phase taking place between the Planck era and today would wash out the CGB, rendering it unobservable: an unambiguous CGB detection would therefore pose a major threat to the inflationary paradigm. In this Letter, we formalize these arguments and discuss prospects for detecting the CGB.We now discuss the features of the CGB in the absence of inflation. We adopt the working assumption that above the Planck scale pointlike four-particle interactions involving two gravitons, whose rate at temperature T is of order , kept gravitons in thermal equilibrium in the primordial plasma (see also Zhao et al. 2009; Giovannini 2020). If we assume adiabatic evolution throughout the early stages of the primordial plasma, and therefore that the universe was radiation dominated up to then, the Hubble rate scales as H ∼ T2/MPl. Comparing the two rates indicates that gravitons decouple at a temperature Tg,dec ∼ MPl (or equivalently around Planck time tg,dec ∼ tPl): besides ruling out inflation, a detection of the CGB would thus provide an experimental test bed for theories attempting to unify quantum mechanics and gravity.Being massless and thus decoupling while relativistic, primordial gravitons preserve the blackbody form of their spectrum following decoupling, with the effective CGB temperature Tg redshifting with the scale factor a as Tg ∝ 1/a. Since the entropy density scales as s ∝ a−3, where is the (temperature-dependent) effective number of entropy degrees of freedom (dof), we can relate the present-day temperatures of the CGB and CMB, Tg,0 and Tγ,0, respectively, as follows:where is the present-day effective number of entropy dof excluding gravitons (accounting for photons and neutrinos), and is the effective number of entropy dof prior to graviton decoupling, including gravitons. Accounting only for standard model (SM) dof up to the Planck scale, above the electroweak (EW) scale . Precise measurements of the CMB frequency spectrum from COBE/FIRAS fix Tγ,0 ≈ 2.7 K and therefore under these minimal assumptions the present-day CGB temperature is predicted to be Tg,0 ≃ (3.91/106.75)1/3 Tγ,0 ≈ 0.9 K, making the CGB about three times colder than the CMB.Lacking a precise knowledge of the type of new physics lying beyond the TeV scale, the assumption of only considering SM dof up to the Planck scale is conservative, but likely somewhat unrealistic, as one might expect several additional dof to appear in the "desert" between the EW and Planck scales. If so, in the denominator of Equation (1) can only increase, decreasing Tg,0 with respect to the previous estimate Tg,0 ≈ 0.9 K, which therefore should be viewed more as a conservative upper bound on Tg,0. However, the exact numbers are highly model dependent and depend on the specific new physics model. For instance, Tg,0 ≈ 0.7 K in a supersymmetric-like scenario where doubles, whereas Tg,0 ≈ 0.4 K in a hypothetical scenario where increases by an order of magnitude.Our assumption of adiabatic evolution from TPl down to present times breaks down whenever comoving entropy is generated, e.g., during reheating at the end of inflation. An inflationary phase alters the relation between Tg,0 and Tγ,0 in Equation (1), as the latter would be determined by the dynamics of reheating, which however can at most produce out-of-equilibrium graviton excitations, unless the effective gravitational constant Geff was significantly higher at reheating. Since the scale factor increases exponentially during inflation, the CGB temperature itself is exponentially suppressed by a factor of e−N , with N the number of e folds of inflation.We can obtain an extremely conservative upper limit on in the presence of a phase of inflation (the tilde distinguishes the present-day graviton temperatures with and without inflation), using the facts that (a) solving the horizon and flatness problems requires N ≳ 60, and (b) reheating should occur at Trh ≳ 5 MeV in order to not spoil Big Bang nucleosynthesis predictions (de Salas et al. 2015). From these requirements we find that , implying that inflation would dilute the CGB to an unobservable level. More generically, we find the following upper limit:However, is a very conservative upper limit, for two reasons. First, in most realistic models inflation typically proceeds for more than 60 e folds, leading to further exponential suppression (see Equation (2)). Next, although reheating at scales as low as is observationally allowed, models realizing this in practice are very hard to construct (see, e.g., Kawasaki et al. 1999; Hannestad 2004; Khoury & Steinhardt 2011). 4 It is far more likely that, if inflation did occur, reheating took place way above the EW scale, further tightening the upper bound on Tg,0.One may try to evade these conclusions invoking models of incomplete inflation with a limited number of e folds 46 ≲ N ≲ 60; however, if inflation is indeed the solution to the flatness problem, such models are essentially ruled out by current stringent bounds on spatial curvature (Vagnozzi et al. 2021), as argued explicitly in Efstathiou & Gratton (2020). Even if N < 60, bringing to a detectable level still requires an extremely low reheating scale, typically harder to achieve within models of incomplete inflation.A caveat to our previous results is our assumption of inflation occurring at sub-Planckian scales. Specifically, Trh > MPl is required for the CGB not to be washed out by inflation. However, on general grounds there are serious concerns about the consistency of trans-Planckian effects both during inflation and at reheating (e.g., Brandenberger & Martin 2013; Brandenberger & Kamali 2022). A specific concern is given by the trans-Planckian censorship conjecture, which sets tight limits on the maximum inflationary scale and reheating temperature: (Bedroya & Vafa 2020; Bedroya et al. 2020; Kamali & Brandenberger 2020; Mizuno et al. 2020).More importantly, the lack of detection of inflationary B modes indicates that is at least 4 orders of magnitude below the Planck scale. For instantaneous reheating, the reheating temperature is obviously limited to , as reheating to higher temperatures would violate (covariant) stress-energy conservation. For noninstantaneous reheating, Trh is of course even lower (see also Cook et al. 2015). Therefore, we deem it very safe to assume that Trh ≪ MPl, corroborating all our earlier findings. In summary, within realistic inflationary cosmologies one does not expect to be able to detect the relic thermal graviton background—conversely, a convincing detection thereof would rule out the inflationary paradigm.We now investigate whether detecting the CGB is experimentally feasible, considering our benchmark Tg,0 ≈0.9 K case. The contribution of the CGB to the effective number of relativistic species Neff is given by:For , we therefore find that ΔNeff,g ≈0.054, as expected for a species with 2 spin dof decoupling before the QCD phase transition.A contribution to Neff of this size is a factor of 3 below the sensitivity of current probes. However, this number is well within the reach of a combination of next-generation CMB and LSS surveys. For instance, even after marginalizing over the total neutrino mass, Brinckmann et al. (2019) forecast a sensitivity of combining CMB data from CMB-S4 and LiteBIRD with galaxy clustering and cosmic shear data from Euclid, whereas with a PICO-like experiment in place of CMB-S4+LiteBIRD the sensitivity improves to . Therefore, if the benchmark 0.9 K CGB were present, CMB-S4+LiteBIRD+Euclid would be able to detect it through its imprint on Neff at ≃2.5σ, whereas PICO+Euclid would be able to do so at ≃3.2σ.Should the CGB contribution to Neff be detected, one may wonder how we know that the excess radiation density is associated to the CGB, rather than another dark radiation component. To remove this ambiguity, we consider the stochastic background of (high-frequency) gravitational waves (GWs) associated to the CGB. It is useful to think in terms of characteristic strain hc , i.e., the dimensionless strain that would be produced due to the passing stochastic GW background (SGWB) in the arms of an interferometer with arms of equal length L in the x- and y-directions, hc (ν) ≃ ΔL/L. The characteristic CGB strain hg (ν) is given by:where h2Ωg (ν) is the CGB spectral energy density in units of the present-day critical density;with h the reduced Hubble parameter, h2Ωγ,0 the photon density parameter today, xg ≡ h ν/(kB Tg,0), and . The CGB spectrum peaks at frequencies ν ≈ 75 GHz, making it a source of high-frequency GWs: Figure 1 shows the characteristic CGB strain alongside demonstrated or forecasted sensitivities of various detector concepts (see Aggarwal et al. 2021).Figure 1. Strain of the CGB stochastic background of high-frequency GWs, alongside the sensitivities of various detector concepts discussed in the main text. The red line ("EMC") refers to enhanced magnetic conversion, with the more transparent extension referring to potential future technological improvements discussed in the main text.Download figure: Standard image High-resolution image Aside from optically levitated sensors (Arvanitaki & Geraci2013) and bulk acoustic wave devices (Goryachev & Tobar2014), all probes in Figure 1 exploit the inverse Gertsenshtein effect (IGE), whereby GWs convert to photons within a strong magnetic field (Gertsenshtein 1962). While apart from small prototypes, dedicated instruments exploiting the IGE do not exist; Ito et al. (2020) and Ejlli et al. (2019) showed how constraints on high-frequency GWs can be obtained reinterpreting data from ongoing or planned axion experiments: in Figure 1 this includes ADMX, SQMS, IAXO, single-photon detectors (SPDs), JURA, OSQAR, and DMRadio8-100 (Domcke et al. 2022). The IGE can also be exploited in strongly magnetized astrophysical environments (Chen 1995; Domcke & Garcia-Cely 2021), recasting observations from radio telescopes such as EDGES and ARCADE. For more details on these detector concepts, see Aggarwal et al. (2021), Berlin et al. (2022), and Domcke et al. (2022).Unfortunately, as is clear from Figure 1, all these detector concepts fall short of the CGB signal by several orders of magnitude. The only promising probe is enhanced magnetic conversion (EMC), a proposal to enhance the efficiency of IGE-based magnetic conversion detectors by seeding the conversion volume with locally generated auxiliary EM fields, e.g., EM Gaussian beams (GBs) oscillating at the frequency of the GW signal searched for (Li & Yang 2004; Baker et al. 2008). Until recently, EMC appeared to be well beyond technological reach, particularly due to the requirement of a GB geometric purity at the 10−21 level to reach strain levels of hc ∼ 10−30 at .However, Ringwald et al. (2021) argued that reaching the above benchmark limit is feasible, exploiting state-of-the-art superconducting magnets utilized in near-future axion experiments to generate the required EM signal, then enhanced by a GB produced by an MW-scale 40 GHz gyrotron. While this still leaves us 2 orders of magnitude short of the CGB peak strain, realistic improvements in the development of gyrotrons, SPDs, and superconducting magnets, can bring the projected sensitivity down to hc ∼ 10−32, sufficient to detect the CGB in our benchmark scenario. We estimate that an increase in the gyrotron available power to ∼100 MW (which is realistically achievable) over a stable running time of ∼1 month (which is much more challenging), alongside improvements in SPD dark count rates to ∼10−5 s−1, would result in a sensitivity to strains of order hc ∼ 10−33, sufficient to detect our benchmark CGB. All quoted sensitivities can be further improved by increasing the reflector size, and the intensity and length of the magnets. Therefore, measuring strains as small as hc ∼ 10−33 at , and detecting the benchmark CGB, might be feasible in the not-too-far-off future. 5 Another interesting potential detection channel proposed very recently by Brandenberger et al. (2022) proceeds through a parametric instability of the EM field in the presence of GWs. This would allow for conversion of high-frequency GWs to photons without the need for a strong background magnetic field. Sensitivity reach estimates for this probe, while not yet available, are worth further investigation in this context.An important issue concerns how to distinguish the CGB from competing SGWB sources. Possible examples could be the SGWB produced during preheating (Easther & Lim 2006) or during oscillon formation (Zhou et al. 2013); however, both these sources are important at lower frequencies, (see Aggarwal et al. 2021), and hence should not confuse the CGB detection. The CGB SGWB can also be distinguished from the SGWB produced by out-of-equilibrium gravitational excitations at reheating (Ringwald et al. 2021); the latter would not be of the blackbody form, and its strength would be orders of magnitude below the CGB as long as the reheating temperature is Trh ≪ MPl, which as argued earlier can be safely assumed. This highlights the importance of detecting the CGB over a range of frequencies, given the clear prediction for its frequency dependence. Within the EMC experimental setup, this can be achieved by tuning the gyrotron frequency; the output frequencies available for typical gyrotrons fall within the ∼20–500 GHz range, perfectly suited to probe the CGB spectrum around its peak frequency. A similar tuning procedure should also be possible for the GW-photon parametric instability probe.A caveat to our findings is the assumption of a pure blackbody spectrum for primordial gravitons. This is likely to be an approximation at best, particularly at low frequencies, whose modes would have been superhorizon at Planck time. However, in the absence of detailed knowledge regarding the underlying theory of quantum gravity, this is among the most conservative assumptions we can make (note that the same approximation has been made in several earlier works discussing primordial gravitons, e.g., Zhao et al. 2009 and Giovannini 2020). Moreover, what is important for our results is the high-frequency tail of the CGB spectrum, where our assumption is likely to be far more realistic. Overall, it remains true that finding any trace of a GW background of the estimated amplitude at the estimated frequency will rule out the standard inflationary scenario.Our previous discussion raises the question of whether an unambiguous CGB detection would also spell trouble for alternative paradigms, where density perturbations are produced during a noninflationary phase. While the answer to this question is highly model dependent, we wish to provide a brief qualitative assessment limited to two well-motivated paradigms: bouncing cosmologies and emergent scenarios.Within bouncing cosmologies, the challenge is to produce a thermal CGB in the first place. This is hard to achieve during the contracting phase, when the characteristic energy scale is typically Λc ≪ MPl (e.g., Brandenberger & Peter 2017). Another possibility is one where a relatively long bouncing phase with energy density around the Planck scale occurs between the initial contracting phase and the later hBB expansion (e.g., Cai 2014), in which case a thermal CGB would be generated and would survive the phase transition between the bouncing and expanding phases.In emergent scenarios, the universe emerges from an initial high density state with matter in global thermal equilibrium, and where producing the CGB is far less unlikely. A particularly well-studied emergent scenario is the string gas proposal of Brandenberger & Vafa (1989), where the universe originates from a quasi-static Hagedorn phase of a string gas at temperature close to the Hagedorn temperature, before a T-dual symmetry breaking-driven phase transition connects to the hBB expansion. On general grounds, the energy density in the emergent phase is close to the Planck density, making it likely for gravitons to be in thermal equilibrium and therefore for a CGB to be generated.However, the initial state in string gas cosmology is not a thermal state of particles but of strings, giving a different scaling of thermodynamical quantities. It is therefore unlikely that the string gas CGB takes the blackbody form, although it is in principle possible that its spectral energy density may be higher than our benchmark CGB, enhancing detection prospects. Fully exploring these points requires a dedicated study, going beyond the scope of our work.Despite its enormous success, recent debates around the inflationary paradigm raise the question of how to model-independently discriminate it from competing scenarios for the production of primordial density perturbations. In this Letter, we have argued that a detection of the CGB, the leftover graviton radiation from the Planck era, would rule out the inflationary paradigm, as realistic inflationary models dilute the CGB to an unobservable level. Assuming the validity of the SM up to the Planck scale, the CGB contribution to the effective number of relativistic species ΔNeff,g ≈ 0.054 is well within the reach of next-generation cosmological probes, whereas detecting the associated stochastic background of high-frequency GWs in the range is challenging but potentially feasible. We also argued that the CGB may be detectable within well-motivated alternatives to inflation such as bouncing and emergent scenarios. We hope that this work will spur further investigation into the possibility of model-independently confirming or ruling out the inflationary paradigm with upcoming observations (for similar endeavors see, e.g., Chen et al. 2019).We are grateful to Robert Brandenberger, Massimo Giovannini, Will Kinney, Nick Rodd, and Luca Visinelli for useful discussions and suggestions. S.V. is partially supported by the Isaac Newton Trust and the Kavli Foundation through a Newton-Kavli Fellowship, by a grant from the Foundation Blanceflor Boncompagni Ludovisi, née Bildt, and by a College Research Associateship at Homerton College, University of Cambridge. A.L. is partially supported by the black hole Initiative at Harvard University, which is funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation.
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Cosmology & The Universe
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Since astronomers first looked beyond the solar system three decades ago to discover extrasolar planets, or exoplanets, we've known that planets in the Milky Way — and probably the wider universe — come in a vast array of widths and masses.
But just how big can these planets get, and what's the biggest planet we know of?
Prior to 1992, when the first exoplanet was discovered, the gas giant Jupiter, which is about 11 times as wide as Earth, held the title of the biggest known planet. But Jupiter is a pip-squeak compared with some monster worlds we've discovered since.
There are two measures to consider when determining the size of a planet: its width (twice its radius) and its mass.
Measuring by the first, "the largest exoplanets have a planetary radius about twice the radius of Jupiter," Solène Ulmer-Moll, a postdoctoral exoplanet researcher at the University of Geneva, told Live Science via email. "These are extreme objects orbiting very close to their host star."
The width of a planet and its mass are linked, but there isn't always a direct correlation between the two. This is because planets vary in density, meaning some low-mass gas giants can "puff out" to sizes greater than other, heavier exoplanets.
For example, the gas giant HAT-P-67 b, which has a radius about twice that of Jupiter, is currently among the largest known planets in terms of width. Yet the exoplanet, which is 1,200 light-years from Earth, has a very low density, so it has only about a third of the mass of Jupiter, Ulmer-Moll said.
WASP-17 b is also roughly twice as wide as Jupiter. A runner-up is KELT-9b, whose radius is 1.84 times Jupiter's, she added.
Most rocky planets elsewhere never get anywhere near as big as the "super-Jupiters" mentioned above. The largest rocky planets, called "super-Earths," are about twice as wide as Earth. "In comparison, Wasp-17b has a radius which is equivalent to 22 times that of Earth," Ulmer-Moll said.
Even though rocky planets are denser than gas giants, they still don't get as heavy as gas giants. That's because as rocky planets grow, they accumulate gas, ice and water that gradually transforms them into gas giants with a rocky center, she said.
The most massive planets are around 13 times the mass of Jupiter. These include the gas giant HD 39091 b, which is located 60 light-years from Earth, and has a mass around 12.3 times that of Jupiter.
How big can a planet actually get?
We don't expect to discover planets much bigger than these super-Jupiters, because a planet becomes a "brown dwarf" once it reaches a certain size and mass.
Brown dwarfs are often referred to as "failed stars" because they are heavier than super-Jupiters but not massive enough to trigger ordinary hydrogen fusion at their cores. But something still burns at the hearts of brown dwarfs.
"The major difference between brown dwarfs and planets is their mass and the occurrence of deuterium — heavy hydrogen — burning," Nolan Grieves, a postdoctoral researcher in the University of Geneva Department of Astronomy, told Live Science via email. "At larger masses, an object will have a high enough internal pressure and temperature to burn most of the deuterium that was initially present in the object."
The dividing line between planets and brown dwarfs was defined back in the 1990s, with brown dwarfs classified as objects that burned 50% or more of their initial deuterium. That dividing line is thought to exist at an upper limit of 14 times the mass of Jupiter, meaning planets shouldn't exist above this cap.
"There are planets that we've measured their mass to be approximately 13 Jupiter masses within the measurement uncertainty, such as HD 39091 b and HD 106906 b , and it could be argued they are the largest known planets," Grieves concluded.
The most massive brown dwarf yet discovered is SDSS J0104+1535, located 750 light-years from Earth at the edge of the Milky Way. It is 90 times more massive than Jupiter, but has a radius between 0.7 and 1.4 times that of Jupiter. So in fact, the most massive brown dwarf might be smaller than the largest planet in our solar system.
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Robert Lea is a science journalist in the U.K. who specializes in science, space, physics, astronomy, astrophysics, cosmology, quantum mechanics and technology. Rob's articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University
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Cosmology & The Universe
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By Munina Lam | Contributing Writer
JET PROPULSION LABORATORY — It is a slide show like no other.
NASA on Tuesday, July 12, began releasing the full set of full-colored “deep field” images and data of distant galaxies captured by the James Webb Space Telescope, the successor of the Hubble telescope.
But this isn’t your everyday scroll through instagram. No no.. This is the epitome of “A long time ago, in a galaxy far, far away…” — as in what are now snapshots of a corner of the universe, capturing light from more than 13 billion years ago, from swirly white specs, faint galaxies, starlight against the darkness. These images are showing the farthest humanity has ever peered outward into the stretches of the universe. And on Tuesday, one by one at the Jet Propulsion Laboratory in La Cañada Flintridge, four galactic shots from the telescope’s initial outward gazes were set to mesmerize even the veteran scientists at JPL who contributed to the mission that would bring those images back to Earth.
The “deep field” images — images that were taken with a long exposure time to capture faint objects — were being released simultaneously across several platforms – NASA Television, Youtube, Twitter, Facebook and more.
Among them, a stunning planetary nebula, now known as the Southern Ring Nebula. The Southern Ring, or “Eight-Burst” nebula, is an expanding cloud of gas, surrounding a dying star. It is about approximately 2,000 light years away from Earth. Some stars go out with a bang. In these images of the Southern Ring planetary nebula, @NASAWebb shows a dying star cloaked by dust and layers of light. Explore this star's final performance at https://t.co/63zxpNDi4I #UnfoldTheUniverse. pic.twitter.com/dfzrpvrewQ
— NASA (@NASA) July 12, 2022 Then there was a “dance,” of sorts. As NASA described it, the telescope peered through the thick dust of Stephan’s Quintet, a galaxy cluster showing huge shockwaves and tidal tails.
“This is a front-row seat to galactic evolution,” wrote NASA on Twitter.
Stephan’s Quintet, a galaxy cluster showing huge shockwaves and tidal tails.
They include a view of a giant gaseous planet outside our solar system, more images of a nebula where stars are born and die in spectacular beauty and an update of a classic image of five tightly clustered galaxies that dance around each other.
The deepest infrared image of the universe ever taken—the first full-color image from NASA’s Webb Telescope. File photo of the James Webb Space Telescope as it was about to begin final assembly at Northrop, (Credit Northrop Grumman Corporation)
Named after NASA’s second administrator James E. Webb, Webb is an international collaborative project between NASA, the European Space Agency and Canadian Space Agency. The $10 billion telescope – the world’s biggest and most powerful – is 21 feet wide and has a sunshield that is a size of a tennis court.
The telescope was rocketed to space last December from French Guiana in South America. It reached its lookout point 1 million miles (1.6 million kilometers) from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool.
The plan is to use the telescope to peer back so far that scientists will get a glimpse of the early days of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus.
Webb will be used to study stars and galaxies that were formed over 13.5 billion years ago with help from its instruments: Near-Infrared Camera (NIRCam), Near-Infrared Spectrograph (NIRSpec), Mid-Infrared Instrument (MIRI), and Near-Infrared Imager and Slitless Spectrograph (NIRISS) with the Fine Guidance Sensor (FGS).
In other words, this is how galaxies looked more than 13 billion years ago.
Researchers can then study how galaxies evolve throughout the years.
The world got a preview on Monday when President Joe Biden unveiled the image of galaxy cluster called SMACS 0723 during a White House event.
Biden marveled at the image that he said showed “the oldest documented light in the history of the universe from over 13 billion — let me say that again — 13 billion years ago. It’s hard to fathom.
NASA administrator Bill Nelson described the image — filled with white, yellow, orange and red swirls, streaks and spirals — as “one little speck of the universe”, according to the Associated Press.
The deep field of SMACS 0723, composited from several different images, took Webb 12.5 hours to produce. In comparison, the same process would have taken its predecessor, Hubble, weeks to achieve.
Vice President Kamala Harris, who is also the chair of the National Space Council, lauded Webb as “one of humanity’s great engineering achievements” at the event, saying, “It will enhance what we know about the origins of our universe, our solar system and, possibly, life itself.”
Biden said that the telescope shows how America can lead by example by participating in an international collaborative effort in discovering more about the planet and climate, symbolizing American ingenuity.
“That’s why the federal government must invest in science and technology more than we have in the past,” he said.
The release of these images marks the start of Webb’s general science operations, where teams of scientists will use the telescope to do research and observations. The teams’ proposals were selected via a rigorous process over the course of the COVID-19 pandemic.
Out of over 1000s proposals, only 286 proposals were selected.
Munina Lam is a freelancer for the Southern California News Group. The Associated Press contributed to this story.
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Cosmology & The Universe
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New images released Wednesday from NASA's James Webb Space Telescope are revealing Neptune, and the planet's hard-to-detect rings, in a fresh light."It has been three decades since we last saw these faint, dusty rings, and this is the first time we've seen them in the infrared," said Heidi Hammel, a Neptune expert and interdisciplinary scientist on the Webb project, in a news release.In addition to several crisp, narrow rings, the Webb images show Neptune's fainter dust bands. Some of the rings haven't been observed since NASA's Voyager 2 got the first photographic proof of the existence of Neptune's rings during its flyby in 1989, CNN reported.Dark, cold and whipped by supersonic winds, Neptune is the most distant planet in our solar system. The planet and its neighbor Uranus are known as "ice giants" because their interiors are made up of heavier elements than the gas giants Jupiter and Saturn, which are richer in hydrogen and helium.In the new images, Neptune looks white, as opposed to the typical blue appearance it has in views captured at visible wavelengths of light. This is because gaseous methane, part of the planet's chemical makeup, doesn't appear blue to Webb's Near-Infrared Camera (NIRCam).Also visible in the images are methane-ice clouds -- bright streaks and spots that reflect sunlight before it is absorbed by methane gas. It's also possible to spot a bright, thin line circling the planet's equator, which could be "a visual signature of global atmospheric circulation that powers Neptune's winds and storms," according to the release.Webb also captured seven of Neptune's 14 known moons, including its largest moon, Triton, which moves around the planet at an unusual backward orbit. Astronomers think Triton was perhaps an object in the Kuiper Belt -- a region of icy objects at the edge of the solar system -- that fell into Neptune's gravitational grasp. Scientists plan to use Webb to further study Triton and Neptune in the coming years.Located 30 times farther from the sun than Earth, Neptune moves through its solar orbit in the remote, dark region of the outer solar system. At that distance, the sun is so small and faint that noon on Neptune is similar to a dim twilight on Earth, the news release said.Webb is a more than 10-year mission run by NASA, the European Space Agency and the Canadian Space Agency.Compared with other telescopes, the space observatory's massive mirror can see fainter galaxies that are farther away and has the potential to enhance scientists' understanding of the origins of the universe. However, it's also using its stable and precise image quality to illuminate our own solar system, with images of Mars, Jupiter and now Neptune. (The-CNN-Wire & 2022 Cable News Network, Inc., a Time Warner Company. All rights reserved.)
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Cosmology & The Universe
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The first full-color image from NASA's James Webb Space Telescope, a revolutionary apparatus designed to peer through the cosmos to the dawn of the universe, shows the galaxy cluster SMACS 0723, known as Webb’s First Deep Field, in a composite made from images at different wavelengths taken with a Near-Infrared Camera and released July 11, 2022.NASA | via ReutersOur view of the universe just expanded: The first image from NASA's new space telescope unveiled Monday is brimming with galaxies and offers the deepest look of the cosmos ever captured.The first image from the $10 billion James Webb Space Telescope is the farthest humanity has ever seen in both time and distance, closer to the dawn of time and the edge of the universe. That image will be followed Tuesday by the release of four more galactic beauty shots from the telescope's initial outward gazes.The "deep field" image released at a White House event is filled with lots of stars, with massive galaxies in the foreground and faint and extremely distant galaxies peeking through here and there. Part of the image is light from not too long after the Big Bang, which was 13.8 billion years ago.Seconds before he unveiled it, President Joe Biden marveled at the image he said showed "the oldest documented light in the history of the universe from over 13 billion -- let me say that again -- 13 billion years ago. It's hard to fathom."The busy image with hundreds of specks, streaks, spirals and swirls of white, yellow, orange and red is only "one little speck of the universe," NASA Administrator Bill Nelson said.The pictures on tap for Tuesday include a view of a giant gaseous planet outside our solar system, two images of a nebula where stars are born and die in spectacular beauty and an update of a classic image of five tightly clustered galaxies that dance around each other.The world's biggest and most powerful space telescope rocketed away last December from French Guiana in South America. It reached its lookout point 1 million miles (1.6 million kilometers) from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool.The plan is to use the telescope to peer back so far that scientists will get a glimpse of the early days of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus.Webb is considered the successor to the highly successful, but aging Hubble Space Telescope. Hubble has stared as far back as 13.4 billion years. It found the light wave signature of an extremely bright galaxy in 2016. Astronomers measure how far back they look in light-years with one light-year being 5.8 trillion miles (9.3 trillion kilometers)."Webb can see backwards in time to just after the Big Bang by looking for galaxies that are so far away that the light has taken many billions of years to get from those galaxies to our telescopes," said Jonathan Gardner, Webb's deputy project scientist said during the media briefing.How far back did that first image look? Over the next few days, astronomers will do intricate calculations to figure out just how old those galaxies are, project scientist Klaus Pontoppidan said last month."The image is spectacularly deeper (than a similar one taken by Hubble), but it's unclear how far back we're looking,″ Richard Ellis, professor of astrophysics at University College London, said by email. "More info is needed."The deepest view of the cosmos "is not a record that will stand for very long," Pontoppidan said, since scientists are expected to use the Webb telescope to go even deeper.Thomas Zurbuchen, NASA's science mission chief said when he saw the images he got emotional and so did his colleagues: "It's really hard to not look at the universe in new light and not just have a moment that is deeply personal."At 21 feet (6.4 meters), Webb's gold-plated, flower-shaped mirror is the biggest and most sensitive ever sent into space. It's comprised of 18 segments, one of which was smacked by a bigger than anticipated micrometeoroid in May. Four previous micrometeoroid strikes to the mirror were smaller. Despite the impacts, the telescope has continued to exceed mission requirements, with barely any data loss, according to NASA.NASA is collaborating on Webb with the European and Canadian space agencies."I'm now really excited as this dramatic progress augurs well for reaching the ultimate prize for many astronomers like myself: pinpointing "Cosmic Dawn" — the moment when the universe was first bathed in starlight," Ellis said.
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Cosmology & The Universe
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For the first time, scientists may have discovered indirect evidence that large amounts of invisible dark matter surround black holes. The discovery, if confirmed, could represent a major breakthrough in dark matter research.
Dark matter makes up around 85% of all matter in the universe, but it is almost completely invisible to astronomers. This is because, unlike the matter that comprises stars, planets and everything else around us, dark matter doesn't interact with light and can't be seen.
Fortunately, dark matter does interact gravitationally, enabling researchers to infer the presence of dark matter by looking at its gravitational effects on ordinary matter "proxies." In the new research, a team of scientists from The Education University of Hong Kong (EdUHK) used stars orbiting black holes in binary systems as these proxies.
The team watched as the orbits of two stars decayed, or slightly slowed, by about 1 millisecond per year while moving around their companion black holes, designated A0620–00 and XTE J1118+480. The team concluded that the slow-down was the result of dark matter surrounding the black holes which generated significant friction and a drag on the stars as they whipped around their high-mass partners.
Using computer simulations of the black hole systems, the team applied a widely held model in cosmology called the dark matter dynamical friction model, which predicts a specific loss of momentum on objects interacting gravitationally with dark matter. The simulations revealed that the observed rates of orbital decay matched the predictions of the friction model. The observed rate of orbital decay is around 50 times greater than the theoretical estimation of about 0.02 milliseconds of orbital decay per year for binary systems lacking dark matter.
"This is the first-ever study to apply the 'dynamical friction model' in an effort to validate and prove the existence of dark matter surrounding black holes," Chan Man Ho (opens in new tab), the team leader and an associate professor in the Department of Science and Environmental Studies at EdUHK, said in a statement (opens in new tab).
The team's results, published Jan. 30 in The Astrophysical Journal Letters (opens in new tab), help to confirm a long-held theory in cosmology that black holes can swallow dark matter that comes close enough to them. This results in the dark matter being redistributed around the black holes, creating a "density spike" in their immediate vicinity that can subtly influence the orbit of surrounding objects.
Chan explained that previous attempts to study dark matter around black holes have relied on the emission of high-energy light in the form of gamma rays, or ripples in space known as gravitational waves. These emissions result from the collision and resulting merger of black holes – a rare event in the universe that can leave astronomers waiting a long time for sufficient data.
This research gives scientists a new way to study dark matter distributed around black holes that may help them to be more proactive in their search. The EdUHK team intends to hunt for similar black hole binary systems to study in the future.
"The study provides an important new direction for future dark matter research," Chan said. "In the Milky Way Galaxy alone, there are at least 18 binary systems akin to our research subjects, which can provide rich information to help unravel the mystery of dark matter."
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Cosmology & The Universe
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By Pallab GhoshScience correspondent, La PalmaImage source, ESOImage caption, Where did the stars in our night sky come from?Scientists have supercharged one of Earth's most powerful telescopes with new technology that will reveal how our galaxy formed in unprecedented detail.The William Herschel Telescope (WHT) in La Palma, Spain will be able to survey 1,000 stars per hour until it has catalogued a total of five million. A super-fast mapping device linked up to WHT will analyse the make-up of each star and the speed at which it travels.It will show how our Milky Way galaxy was built up over billions of years.Prof Gavin Dalton of Oxford University has spent more than a decade developing the instrument, known as 'Weave'.He told me that he was "beyond excited" that it is ready to go."It's a fantastic achievement from a lot of people to make this happen and it's great to have it working," he said. "The next step is the new adventure, it's brilliant!"Image source, Gavin DaltonImage caption, Weave's nimble robotic fingers position a thousand fibre optics precisely, each one pointed at a starWeave has been installed on the WHT, which sits high on a mountain top on the Spanish Canary Island of La Palma. The name stands for WHT Enhanced Area Velocity Explorer - and that's exactly what it does.It has 80,000 separate parts and is a miracle of engineering.For each patch of sky the WHT is pointed at, astronomers identify the positions of a thousand stars. Weave's nimble robotic fingers then carefully place a fibre-optic - a light-transmitting tube - precisely on each location on a plate, pointing towards its corresponding star.These fibres are in effect tiny telescopes. Each one captures light from a single star and channels it to another instrument. This then splits it into a rainbow spectrum, which contains the secrets of the star's origin and history.All this is completed in just one hour. While this is going on, fibre optics for the next thousand stars are positioned on the reverse side of the plate, which flips over to analyse the next set of targets once the previous survey has been completed.Image source, Science Photo LibraryImage caption, Artwork: The Milky Way is surrounded by "dwarf" satellite galaxiesOur galaxy is a dense spiral swirl of up to 400 billion stars. But it started out as a relatively small collection of stars.It grew from successive mergers with other small galaxies over billions of years. As well as the addition of stars from the new galaxies joining ours, each merger stirs things up enough to lead to brand new star formation. Weave is able to calculate the speed, direction, age and composition of each star it observes, essentially creating a motion picture of stars moving in the Milky Way. According to Prof Dalton, by extrapolating backwards, it will be possible to reconstruct the entire formation of the Milky Way in detail never seen before."We'll be able to trace the galaxies that have been absorbed as the Milky Way has been built up over cosmic time - and see how each absorption triggers new star formation," he said.Dr Marc Balcells, who is in overall charge of the WHT told BBC News that he believed that Weave would lead to a big shift in our understanding of how galaxies are made.''We have been hearing for decades that we are in a golden era of astronomy - but what the future awaits is a lot more important. "Weave is going to be answering questions that astronomers have been trying to be answer for decades such as how many pieces come together to make a big galaxy and how many galaxies were united to make the Milky Way?"Image source, BBC NewsImage caption, Instrumentation specialist Dr Cecilia Farina says that Weave might discover completely unexpected phenomenonDr Cecilia Farina, an instrumentation specialist on the project, said she believed that Weave would make astronomical history."There are an enormous amount of things that we are going to discover that we had not expected to find," she said. "Because the Universe is full of surprises." You can see Weave and other new telescopes in action in a short film, The Cosmic Hunters, on BBC iPlayer.Related Internet LinksThe BBC is not responsible for the content of external sites.
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Cosmology & The Universe
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In the first data taken last summer with the Near Infrared Camera (NIRCam) on the new James Webb Space Telescope, astronomers found six galaxies from a time when the Universe was only 3% of its current age, just 500-700 million years after the Big Bang. While its incredible JWST saw these galaxies from so long ago, the data also pose a mystery.
These galaxies should be mere infants, but instead they resemble galaxies of today, containing 100 times more stellar mass than astronomers were expecting to see so soon after the beginning of the Universe. If confirmed, this finding calls into question the current thinking of galaxy formation and challenges most models of cosmology.
“These objects are way more massive than anyone expected,” said Joel Leja, assistant professor of astronomy and astrophysics at Penn State, who modeled light from these galaxies. “We expected only to find tiny, young, baby galaxies at this point in time, but we’ve discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe.”
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The data was taken by JWST as part of the Cosmic Evolution Early Release Science (CEERS) program and was the first dataset released as part of the telescope’s early release program, which is helping to showcase the new telescope’s observing capabilities and allow the astronomical community to learn how to get the most out of their observing time with the various instruments.
NIRCam’s infrared eyes are capable of detecting light that was emitted by the oldest stars and galaxies, allowing scientists to see back in time roughly 13.5 billion years, near the beginning of the universe as we know it. The targeted area of the sky for these sets of observations was a “blank” field – where no stars or galaxies had ever been seen before — and overlapped with existing Hubble Space Telescope (HST) imaging.
While large galaxies with stellar masses as high as 100 billion times that of the Sun have been identified previously at approximately one billion years after the Big Bang, it has been difficult to find massive galaxies at even earlier times, the team wrote in their paper, published in Nature.
Within the JWST early release observation data, the team searched for intrinsically high redshifted galaxies in the first 500- 750 million years of cosmic history. Redshift is a measure of the age of an astronomical object, as due to the expansion of the Universe, light from distant objects shifts to wavelengths towards the red end of the spectrum. The redder the image, the more distant the object is.
They found six candidate massive galaxies at high redshifts (z = 6.5 and z = 9.1), with masses up to ten billion times that of our Sun, including one galaxy with a possible stellar mass 100 billion times that of the Sun. This is much bigger than anticipated.
“We looked into the very early universe for the first time and had no idea what we were going to find,” Leja said, in a press release. “It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question.”
Leja explained that the galaxies the team discovered are so massive that they are in conflict with 99% of models for cosmology. Accounting for such a high amount of mass would require either altering the models for cosmology or revising the scientific understanding of galaxy formation in the early universe. Either scenario requires a fundamental shift in our understanding of how the universe came to be, he added.
However, the team needs more observations and data to confirm their findings, and admitted more data might reveal other explanations for what they found.
“This is our first glimpse back this far, so it’s important that we keep an open mind about what we are seeing,” Leja said. “While the data indicates they are likely galaxies, I think there is a real possibility that a few of these objects turn out to be obscured supermassive black holes. Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought. Even if we cut the sample in half, this is still an astounding change.”
The plan is to take more data on these galaxies with NIRCam, and which will provide more details on how and distant these galaxies are. and how far away they are.
“What’s funny is we have all these things we hope to learn from James Webb and this was nowhere near the top of the list,” Leja said. “We’ve found something we never thought to ask the universe — and it happened way faster than I thought, but here we are.”
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Cosmology & The Universe
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GREENBELT, Md., July 12 (Reuters) - NASA on Tuesday drew back the curtain on billions of years of cosmic evolution with the inaugural batch of photos from the largest, most powerful observatory ever launched to space, saying the luminous imagery showed the telescope exceeds expectations.The first full-color, high-resolution pictures from the James Webb Space Telescope, designed to peer farther than before with greater clarity to the dawn of the universe, were hailed by NASA as milestone marking a new era of astronomical exploration.Nearly two decades in the making and built under contract for NASA by aerospace giant Northrop Grumman Corp , the $9 billion infrared telescope was launched on Dec. 25, 2021. It reached its destination in solar orbit nearly 1 million miles from Earth a month later.Register now for FREE unlimited access to Reuters.comWith Webb finely tuned after months spent remotely aligning its mirrors and calibrating its instruments, scientists will embark on a competitively selected agenda exploring the evolution of galaxies, life cycle of stars, atmospheres of distant exoplanets, and moons of our outer solar system."All of us are just blown away," Amber Straughn, Webb deputy project scientist at NASA's Goddard Space Flight Center in Maryland, said among a panel of experts who briefed reporters following the big reveal.Whoops and hollers from a sprightly "cheer team" welcomed some 300 scientists, telescope engineers, politicians and senior officials from NASA and its international partners into a packed and auditorium at Goddard for the official unveiling."I didn't know I was coming to a pep rally," NASA Administrator James Nelson said from the stage, enthusing that Webb's "every image is a discovery."The event was simulcast to watch parties of astronomy enthusiasts worldwide, from Bhopal, India, to Vancouver, British Columbia.The first photos, which took weeks to render from raw telescope data, were selected by NASA to show off Webb's capabilities and foreshadow science missions ahead.The crowning debut image, previewed on Monday by U.S. President Biden but displayed with greater fanfare on Tuesday, was a "deep field" photo of a distant galaxy cluster, SMACS 0723, revealing the most detailed glimpse of the early universe recorded to date.At least one faint galaxy measured among the thousands in the image is nearly 95% as old as the Big Bang, the theoretical flashpoint that set the expansion of the known universe in motion some 13.8 billion years ago, NASA said.Among the four other Webb subjects getting their closeups on Tuesday were two enormous clouds of gas and dust blasted into space by stellar explosions to form incubators for new stars - the Carina Nebula and the Southern Ring Nebula, each thousands of light years away from Earth.The "Cosmic Cliffs" of the Carina Nebula is seen in an image divided horizontally by an undulating line between a cloudscape forming a nebula along the bottom portion and a comparatively clear upper portion, with data from NASA's James Webb Space Telescope, a revolutionary apparatus designed to peer through the cosmos to the dawn of the universe and released July 12, 2022. Speckled across both portions is a starfield, showing innumerable stars of many sizes. NASA, ESA, CSA, STScI, Webb ERO Production Team/Handout via REUTERSThe collection also included fresh images of another galaxy cluster known as Stephan's Quintet, first discovered in 1877, which encompasses several galaxies NASA described as "locked in a cosmic dance of repeated close encounters."Apart from the imagery, NASA presented Webb's first spectrographic analysis of a Jupiter-sized exoplanet more than 1,100 light years away - revealing the molecular signatures of filtered light passing through its atmosphere, including the presence of water vapor. Scientists have raised the possibility of eventually detecting water on the surface of smaller, rockier Earth-like exoplanets in the future.'PIECE OF ART'Built to view its subjects chiefly in the infrared spectrum, Webb is about 100 times more sensitive than its 30-year-old predecessor, the Hubble Space Telescope, which operates mainly at optical and ultraviolet wavelengths.The much larger light-collecting surface of Webb's primary mirror - an array of 18 hexagonal segments of gold-coated beryllium metal - enables it to observe objects at greater distances, thus further back in time, than any other telescope. Its infrared optics allow Webb to detect a wider range of celestial objects and see through clouds of dust and gas that obscure light in the visible spectrum.All five of Webb's introductory targets were previously known to scientists, but NASA officials said Webb's early imagery proved it works as designed, better than expected, while literally capturing its subjects in an entirely new light.The image of Southern Ring Nebula, for instance, clearly showed the dying stellar object at its center was a binary pair of stars closely orbiting one another. The new Carina Nebula photos exposed contours of its massive clouds never seen before."This is an art piece that has been revealed by this telescope," Rene Doyon, principal investigator for the observatory's Canadian-built near-infrared camera and spectrograph. "It goes beyond my scientific mind."The SMACS 0723 image showed a 4.6 billion-year-old galaxy cluster whose combined mass acts as a "gravitational lens," distorting space to greatly magnify light coming from more distant galaxies behind it.One of the older galaxies appearing in the "background" of the photo - a composite of images of different wavelengths of light - dates back about 13.1 billion years.The bejeweled-like photo, according to NASA, offers the "most detailed view of the early universe" as well as the "deepest and sharpest infrared image of the distant cosmos" yet taken.Underscoring the vastness of the universe, the thousands of galaxies appearing in the SMACS 0723 image appear in a tiny patch of sky roughly the size of a sand grain held at arm's length by someone standing on Earth.The Webb telescope is an international collaboration led by NASA in partnership with the European and Canadian space agencies.Register now for FREE unlimited access to Reuters.comReporting by Joey Roulette in Greenbelt, Md.; Writing and additional reporting by Steve Gorman in Los Angeles; Editing by Raju Gopalakrishnan, Nick Zieminski and Richard ChangOur Standards: The Thomson Reuters Trust Principles.
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Cosmology & The Universe
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Six massive galaxies discovered in the early universe are upending what scientists previously understood about the origins of galaxies in the universe.
"These objects are way more massive? than anyone expected," said Joel Leja, assistant professor of astronomy and astrophysics at Penn State, who modeled light from these galaxies. "We expected only to find tiny, young, baby galaxies at this point in time, but we've discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe."
Using the first dataset released from NASA's James Webb Space Telescope, the international team of scientists discovered objects as mature as the Milky Way when the universe was only 3% of its current age, about 500-700 million years after the Big Bang. The telescope is equipped with infrared-sensing instruments capable of detecting light that was emitted by the most ancient stars and galaxies. Essentially, the telescope allows scientists to see back in time roughly 13.5 billion years, near the beginning of the universe as we know it, Leja explained.
"This is our first glimpse back this far, so it's important that we keep an open mind about what we are seeing," Leja said. "While the data indicates they are likely galaxies, I think there is a real possibility that a few of these objects turn out to be obscured supermassive black holes. Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought. Even if we cut the sample in half, this is still an astounding change."
In a paper published today (Feb. 22) in Nature, the researchers show evidence that the six galaxies are far more massive than anyone expected and call into question what scientists previously understood about galaxy formation at the very beginning of the universe.
"The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science," said Leja. "We've been informally calling these objects 'universe breakers' -- and they have been living up to their name so far."
Leja explained that the galaxies the team discovered are so massive that they are in tension with 99% percent of models for cosmology. Accounting for such a high amount of mass would require either altering the models for cosmology or revising the scientific understanding of galaxy formation in the early universe -- that galaxies started as small clouds of stars and dust that gradually grew larger over time. Either scenario requires a fundamental shift in our understanding of how the universe came to be, he added.
"We looked into the very early universe for the first time and had no idea what we were going to find," Leja said. "It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question."
On July 12, NASA released the first full-color images and spectroscopic data from the James Webb Space Telescope. The largest infrared telescope in space, Webb was designed to see the genesis of the cosmos, its high resolution allowing it to view objects too old, distant or faint for the Hubble Space Telescope.
"When we got the data, everyone just started diving in and these massive things popped out really fast," Leja said. "We started doing the modeling and tried to figure out what they were, because they were so big and bright. My first thought was we had made a mistake and we would just find it and move on with our lives. But we have yet to find that mistake, despite a lot of trying."
Leja explained that one way to confirm the team's finding and alleviate any remaining concerns would be to take a spectrum image of the massive galaxies. That would provide the team data on the true distances, and also the gasses and other elements that made up the galaxies. The team could then use the data to model a clearer of picture of what the galaxies looked like, and how massive they truly were.
"A spectrum will immediately tell us whether or not these things are real," Leja said. "It will show us how big they are, how far away they are. What's funny is we have all these things we hope to learn from James Webb and this was nowhere near the top of the list. We've found something we never thought to ask the universe -- and it happened way faster than I thought, but here we are."
The other co-authors on the paper are Elijah Mathews and Bingjie Wang of Penn State, Ivo Labbe of the Swinburne University of Technology, Pieter van Dokkum of Yale University, Erica Nelson of the University of Colorado, Rachel Bezanson of the University of Pittsburgh, Katherine A. Suess of the University of California and Stanford University, Gabriel Brammer of the University of Copenhagen, Katherine Whitaker of the University of Massachusetts and the University of Copenhagen, and Mauro Stefanon of the Universitat de Valencia.
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Cosmology & The Universe
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Published July 12, 2022 8:42AM Updated 10:48AM article Two of the images showing emerging stellar nurseries and individual stars in the Carina Nebula (L) and never-before-seen details of the galaxy group "Stephan’s Quintet" (R) released by NASA from its James Webb Space Telescope during an event on July GREENBELT, Md. - The first full round of galactic beauty shots from NASA’s new James Webb Space Telescope were unveiled on Tuesday, including a foamy blue and orange shot of a dying star and parts of the universe seen in a new light. NASA shared four more images from the $10-billion telescope’s initial outward gazes, including two images of nebulas where stars are born and die in spectacular beauty and another shot showing an update of a classic image of five tightly clustered galaxies that dance around each other. The first image, offering the farthest humanity has ever seen in both time and distance, was unveiled Monday. With one exception, the latest images on Tuesday showed parts of the universe seen by other telescopes. But Webb’s sheer power, distant location off Earth, and use of the infrared light spectrum showed them in a new light. "Every image is a new discovery and each will give humanity a view of the humanity that we’ve never seen before,’’ NASA Administrator Bill Nelson said Tuesday, rhapsodizing over images showing "the formation of stars, devouring black holes." Webb's use of the infrared light spectrum allows the telescope to see through the cosmic dust and "see light from faraway light from the corners of the universe," he said. "We’ve really changed the understanding of our universe," said European Space Agency director general Josef Aschbacher. The European and Canadian space agencies joined NASA in building the powerful telescope. "For everyone on Earth, this is your telescope," NASA said in its broadcast on Tuesday, which shared live videos of groups watching the event in India, Italy, Israel, and other countries around the world. "Today actually does mark the dawn of a new era... this is just the beginning." The Southern Ring Nebula, which is sometimes called "eight-burst" was pictured in one of the images released. About 2,500 light-years away, it shows an expanding cloud of gas surrounding a dying star. A light-year is 5.8 trillion miles. NASA’s James Webb Space Telescope has revealed details of the Southern Ring planetary nebula that were previously hidden from astronomers. Planetary nebulae are the shells of gas and dust ejected from dying stars. Image credit: NASA, ESA, CSA, and ST Another image showed Carina Nebula, one of the bright stellar nurseries in the sky, about 7,600 light-years away. NASA’s James Webb Space Telescope reveals emerging stellar nurseries and individual stars in the Carina Nebula that were previously obscured. Images of "Cosmic Cliffs" showcase Webb’s cameras’ capabilities to peer through cosmic dust, shedding new li A third image revealed never-before-seen details of five galaxies in a cosmic dance, some 290 million light-years away. "Stephan’s Quintet" was first seen 225 years ago in the constellation Pegasus. In an enormous new image, NASA’s James Webb Space Telescope reveals never-before-seen details of the galaxy group "Stephan’s Quintet." The close proximity of Stephan’s Quintet gives astronomers a ringside seat to galactic mergers and interactions. We The fourth image is about a blueish giant planet called WASP-96b. The telescope captured the distinct signature of water, along with evidence of clouds and haze, in the atmosphere surrounding a hot, puffy gas giant planet orbiting a distant Sun-like star. "The observation, which reveals the presence of specific gas molecules based on tiny decreases in the brightness of precise colors of light, is the most detailed of its kind to date, demonstrating Webb’s unprecedented ability to analyze atmospheres hundreds of light-years away," NASA said. NASA’s James Webb Space Telescope has captured the distinct signature of water, along with evidence for clouds and haze, in the atmosphere surrounding a hot, puffy gas giant planet orbiting a distant Sun-like star. The observation, which reveals the The first "deep field" image, released during a brief White House event, is filled with lots of stars, with massive galaxies in the foreground and faint and extremely distant galaxies peeking through here and there. Part of the image is light from not too long after the Big Bang, which was 13.8 billion years ago. It's the first to utilize Deep Field abilities and contains a cluster of galaxies known as SMACS 0723. NASA’s James Webb Space Telescope has produced the deepest and sharpest infrared image of the distant universe to date. Known as Webb’s First Deep Field, this image of galaxy cluster SMACS 0723 is overflowing with detail. This image is among the tele (NASA, ESA, CSA, and STScI) President Joe Biden marveled at the image that he said showed "the oldest documented light in the history of the universe from over 13 billion — let me say that again — 13 billion years ago. It’s hard to fathom." The busy image with hundreds of specks, streaks, spirals and swirls of white, yellow, orange and red is only "one little speck of the universe," NASA Administrator Bill Nelson said. "What we saw today is the early universe," Harvard astronomer Dimitar Sasselov told the Associated Press after the Monday reveal. Sasselov said he and his colleague Charles Alcock first thought "we’ve seen this before." Then they looked closer at the image and pronounced the result not only beautiful but "worth all that waiting" for the much-delayed project. What is the James Webb Space Telescope? The world’s biggest and most powerful space telescope rocketed away last December from French Guiana in South America. In January, it reached its lookout point of 1 million miles from Earth. That’s when the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate, and calibrate the science instruments — all protected by a sunshade the size of a tennis court that keeps the telescope cool. The plan is to use the telescope to peer back so far that scientists will get a glimpse of the early days of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with a sharper focus. How does James Webb Space Telescope compare to Hubble Space Telescope? The Hubble Space Telescope was launched into orbit by space shuttle Discovery in 1990, helping scientists to better understand how planets and galaxies form with its own awe-inspiring images. The James Webb Space Telescope is Hubble’s bigger, more powerful successor. Specifically, Webb is designed to peer deeper into space to see the earliest stars and galaxies that formed in the universe and to look deep into nearby dust clouds to study the formation of stars and planets, NASA says. To do this, Webb has a much larger primary mirror than Hubble — 2.7 times larger in diameter — which gives it more light-gathering power. Its infrared instruments also have longer wavelength coverage and more improved sensitivity compared to Hubble. Hubble has stared as far back as 13.4 billion years, disclosing a clumpy runt of a galaxy that is currently the oldest and farthest object ever observed. Astronomers are eager to close the 300 million-year gap with Webb and draw ever closer in time to the Big Bang, the moment the universe formed 13.8 billion years ago. FULL INTERVIEW: NASA astronomer discusses Hubble Telescope's' new discovery NASA announced an extraordinary new benchmark: the detection of the farthest individual star to date. (Credit: NASA) How far back past 13 billion years did that first image look? NASA didn't provide any estimate on Monday. Outside scientists said those calculations will take time, but they are fairly certain somewhere in the busy image is a galaxy older than humanity has ever seen, probably back to 500 million or 600 million years after the Big Bang. "It takes a little bit of time to dig out those galaxies," University of California, Santa Cruz, astrophysicist Garth Illingworth said. "It's the things you almost can't see here, the tiniest little red dots." "This is absolutely spectacular, absolutely amazing," he added. "This is everything we’ve dreamed of in a telescope like this." The deepest view of the cosmos "is not a record that will stand for very long," project scientist Klaus Pontoppidan said during the briefing, since scientists are expected to use the Webb telescope to go even deeper. This story was reported from Cincinnati. The Associated Press contributed.
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Cosmology & The Universe
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The James Webb space telescope has detected what appear to be six massive ancient galaxies, which astronomers are calling “universe breakers” because their existence could upend current theories of cosmology.
The objects date to a time when the universe was just 3% of its current age and are far larger than was presumed possible for galaxies so early after the big bang. If confirmed, the findings would call into question scientists’ understanding of how the earliest galaxies formed.
“These objects are way more massive than anyone expected,” said Joel Leja, an assistant professor of astronomy and astrophysics at Penn State University and a study co-author. “We expected only to find tiny, young, baby galaxies at this point in time, but we’ve discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe.”
The observations come from the first dataset released from Nasa’s James Webb space telescope, which is equipped with infrared-sensing instruments capable of detecting light emitted by the most ancient stars and galaxies. While sifting through images, Dr Erica Nelson, of the University of Colorado Boulder, and a co-author, spotted a series of “fuzzy dots” that appeared unusually bright and unusually red.
Redness in astronomy is a proxy for age, because as light travels across the expanding universe it is stretched out, or red-shifted. These galaxies appeared to be roughly 13.5bn years old, placing them about 500m-700m years after the big bang.
These would not be the oldest galaxies observed by James Webb, which launched in December 2021. Last year, scientists spotted four galaxies that date to about 350m years after the big bang, but these were far smaller. Calculations suggest the latest galaxies harboured tens to hundreds of billions of sun-sized stars’ worth of mass, putting them on par with the Milky Way.
“It’s bananas,” said Nelson. “These galaxies should not have had time to form.”
Explaining the existence of such massive galaxies close to the dawn of time would require scientists to revisit either some basic rules of cosmology or the understanding of how the first galaxies were seeded from small clouds of stars and dust.
“It turns out we found something so unexpected it actually creates problems for science,” said Leja. “It calls the whole picture of early galaxy formation into question.”
Existing models suggest that after a period of rapid expansion, the universe spent a few hundred million years cooling down enough for gas to coalesce and collapse into the first stars and galaxies began to form, a period known as the dark ages.
“The discovery of such massive galaxies so soon after the big bang suggests that the dark ages may not have been so dark after all, and that the universe may have been awash with star formation far earlier than we thought,” said Dr Emma Chapman, an astrophysicist at the University of Nottingham, who was not involved in the latest observations.
Chapman said that further observations would be required to confirm the discovery before existing models could be abandoned. “Saying that, with the pace that JWST has been upturning theories and revolutionising whole fields, it wouldn’t surprise me if it were true!” she added.
The team are planning to obtain spectrum images, which can provide more accurate distance information and allow better estimates of mass. “A spectrum will immediately tell us whether or not these things are real,” Leja said.
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Cosmology & The Universe
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By Matt WilliamsDuring the 1930s, astronomers came to realize that the Universe is in a state of expansion. By the 1990s, they realized that the rate at which it is expansion is accelerating, giving rise to the theory of “Dark Energy”. Because of this, it is estimated that in the next 100 billion years, all stars within the Local Group – the part of the Universe that includes a total of 54 galaxies, including the Milky Way – will expand beyond the cosmic horizon. This illustration shows the evolution of the Universe, from the Big Bang on the left, to modern times on the right. - Image Credit: NASA At this point, these stars will no longer be observable, but inaccessible – meaning that no advanced civilization will be able to harness their energy. Addressing this, Dr. Dan Hooper – an astrophysicist from the Fermi National Accelerator Laboratory (FNAL) and the University of Chicago – recently conducted a study that indicated how a sufficiently advanced civilization might be able to harvest these stars and prevent them from expanding outward.For the sake of his study, which recently appeared online under the title “Life Versus Dark Energy: How An Advanced Civilization Could Resist the Accelerating Expansion of the Universe“, Dr. Dan Hooper considered how civilizations might be able to reverse the process of cosmic expansion. In addition, he suggests ways in which humanity might looks for signs of such a civilization.To put it simply, the theory of Dark Energy is that space is filled with a mysterious invisible force that counteracts gravity and causes the Universe to expand at an accelerating rate. The theory originated with Einstein’s Cosmological Constant, a term he added to his theory of General Relativity to explain how the Universe could remain static, rather than be in a state of expansion or contraction. While Einstein was proven wrong, thanks to observations that showed that the Universe was expanding, scientists revisited the concept in order to explain how cosmic expansion has sped up in the past few billion years. The only problem with this theory, according to Dr. Hooper’s study, is that the dark energy will eventually become dominant, and the rate of cosmic expansion Universe will increase exponentially.As a result, the Universe will expand to the point where all stars are so far apart that intelligent species won’t even be able to see them, let alone explore them or harness their energy. As Dr. Hooper told Universe Today via email:“Cosmologists have learned over the last 20 years that our universe is expanding at an accelerating rate. This means that over the next 100 billion years or so, most of the stars and galaxies that we can now see in the sky will disappear forever, falling beyond any regions of space that we could reach, even in principle. This will limit the ability of a far-future advanced civilization to collect energy, and thus limit any number of things they might want to accomplish.” Illustration showing the Lamba Cold Dark Matter (LCDM) model, which indicates how the influence of dark energy has led to an accelerated rate of cosmic expansion. - Image Credit: Wikimedia Commons/Alex Mittelmann In addition to being the Head of the Theoretical Astrophysics Group at the FNAL, Dr. Hooper is also an Associate Professor in the Department of Astronomy and Astrophysics at the University of Chicago. As such, he is well versed when it comes to the big questions of extra-terrestrial intelligence (ETI) and how cosmic evolution will affect intelligent species.To tackle how advanced civilizations would go about living in such a Universe, Dr. Hooper begins by assuming that the civilizations in question would be a Type III on the Kardashev scale. Named in honor of Russian astrophysicist Nikolai Kardashev, a Type III civilization would have reached galactic proportions and could control energy on a galactic scale. As Hooper indicated:“In my paper, I suggest that the rational reaction to this problem would be for the civilization to expand outward rapidly, capturing stars and transporting them to the central civilization, where they could be put to use. These stars could be transported using the energy they produce themselves.”As Dr. Hooper admits, this conclusion relies on two assumptions – first, that a highly advanced civilization will attempt to maximize its access to usable energy; and second, that our current understanding of dark energy and the future expansion of our Universe is approximately correct. With this in mind, Dr. Hooper attempted to calculate which stars could be harvested using Dyson Spheres and other megastructures. This harvesting, according to Dr. Hooper, would consist of building unconventional Dyson Spheres that would use the energy they collected from stars to propel them towards the center of the species’ civilization. High-mass stars are likely to evolve beyond the main sequence before reaching the destination of the central civilization and low-mass stars would not generate enough energy (and therefore acceleration) to avoid falling beyond the horizon.For these reasons, Dr. Hooper concludes that stars with masses of between 0.2 and 1 Solar Masses will be the most attractive targets for harvesting. In other words, stars that are like our Sun (G-type, or yellow dwarf), orange dwarfs (K-type), and some M-type (red dwarf) stars would all be suitable for a Type III civilization’s purposes. As Dr. Hooper indicates, there would be limiting factors that have to be considered:“Very small stars often do not produce enough energy to get them back to the central civilization. On the other hand, very large stars are short lived and will run out of nuclear fuel before they reach their destination. Thus the best targets of this kind of program would be stars similar in size (or a little smaller) than the Sun.”Based on the assumption that such a civilization could travel at 1 – 10% the speed of light, Dr. Hooper estimates that they would be able to harvest stars out to a co-moving radius of approximately 20 to 50 Megaparsecs (about 652,300 to 163,000 light-years). Depending on their age, 1 to 5 billion years, they would be able to harvest stars within a range of 1 to 4 Megaparsecs (3,260 to 13,046 light-years) or up to several tens of Megaparsecs. In addition to providing a framework for how a sufficiently-advanced civilization could survive cosmic acceleration, Dr. Hooper’s paper also provides new possibilities in the search for extra-terrestrial intelligence (SETI). While his study primarily addresses the possibility that such a mega-civilization will emerge in the future (perhaps it will even be our own), he also acknowledges the possibility that one could already exist.In the past, scientists have suggested looking for Dyson Spheres and other megastructures in the Universe by looking for signatures in the infrared or sub-millimeter bands. However, megastructures that have been built to completely harvest the energy of a star, and use it to transport them across space at relativistic speeds, would emit entirely different signatures.In addition, the presence of such a mega-civilization could be discerned by looking at other galaxies and regions of space to see if a harvesting and transport process has already begun (or is in an advanced stage). Whereas past searchers for Dyson Spheres have focused on detecting the presence of structures around individual stars within the Milky Way, this kind of search would focus on galaxies or groups of galaxies in which most of the stars would be surrounded by Dyson Spheres and removed.“This provides us with a very different signal to look for,” said Dr. Hooper. “An advanced civilization that is in the process of this program would alter the distribution of stars over regions of space tens of millions of light years in extent, and would likely produce other signals as a result of stellar propulsion.”In the end, this theory not only provides a possible solution for how advanced species might survive cosmic expansion, it also offers new possibilities in the hunt for extra-terrestrial intelligence. With next-generation instruments looking farther into the Universe and with greater resolution, perhaps we should be on the lookout for hypervelocity stars that are all being transported to the same region of space.Could be a Type III civilization preparing for the day when dark energy takes over!Source: Universe Today - Further Reading: arXiv If you enjoy our selection of content please consider following Universal-Sci on social media:
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Cosmology & The Universe
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One of the most interesting and important questions in cosmology is, "How much matter exists in the universe?" An international team, including scientists at Chiba University, has now succeeded in measuring the total amount of matter for the second time. Reporting in The Astrophysical Journal, the team determined that matter makes up 31% of the total amount of matter and energy in the universe, with the remainder consisting of dark energy.
"Cosmologists believe that only about 20% of the total matter is made of regular or 'baryonic' matter, which includes stars, galaxies, atoms, and life," explains first author Dr. Mohamed Abdullah, a researcher at the National Research Institute of Astronomy and Geophysics-Egypt, Chiba University, Japan. "About 80% is made of dark matter, whose mysterious nature is not yet known but may consist of some as-yet-undiscovered subatomic particles."
"The team used a well-proven technique to determine the total amount of matter in the universe, which is to compare the observed number and mass of galaxy clusters per unit volume with predictions from numerical simulations," says co-author Gillian Wilson, Abdullah's former graduate advisor and Professor of Physics and Vice Chancellor for research, innovation, and economic development at UC Merced. "The number of clusters observed at the present time, the so-called 'cluster abundance,' is very sensitive to cosmological conditions and, in particular, the total amount of matter."
"A higher percentage of the total matter in the universe would result in more clusters being formed," says Anatoly Klypin from University of Virginia. "But it is difficult to measure the mass of any galaxy cluster accurately as most of the matter is dark, and we cannot see it directly with telescopes."
To overcome this difficulty, the team was forced to use an indirect tracer of cluster mass. They relied upon the fact that more massive clusters contain more galaxies than less massive clusters (mass richness relation: MRR). Because galaxies consist of luminous stars, the number of galaxies in each cluster can be utilized as a way of indirectly determining its total mass. By measuring the number of galaxies in each cluster in their sample from the Sloan Digital Sky Survey, the team was able to estimate the total mass of each of the clusters. They were then able to compare the observed number and mass of galaxy clusters per unit volume against predictions from numerical simulations. The best-fit match between observations and simulations was with a universe consisting of 31% of the total matter, a value that was in excellent agreement with that obtained using cosmic microwave background (CMB) observations from the Planck satellite. Notably, CMB is a completely independent technique.
"We have succeeded in making the first measurement of matter density using the MRR, which is in excellent agreement with that obtained by the Planck team using the CMB method," says Tomoaki Ishiyama from Chiba University. "This work further demonstrates that cluster abundance is a competitive technique for constraining cosmological parameters and complementary to non-cluster techniques such as CMB anisotropies, baryon acoustic oscillations, Type Ia supernovae, or gravitational lensing."
The team credits their achievement as being the first to successfully utilize spectroscopy, the technique that separates radiation into a spectrum of individual bands or colors, to precisely determine the distance to each cluster and the true member galaxies that are gravitationally bound to the cluster rather than background or foreground interlopers along the line of sight. Previous studies that attempted to use the MRR technique relied on much cruder and less accurate imaging techniques, such as using pictures of the sky taken at some wavelengths, to determine the distance to each cluster and the nearby galaxies that were true members.
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Cosmology & The Universe
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Our picture of cosmic evolution could be thrown into doubt by the discovery of a massive galaxy that seems to lack dark matter.
Dark matter, which accounts for around 85% of the matter in the universe, seems to be absent from the galaxy NGC 1277, part of the Perseus Cluster of galaxies. The galaxy, located 240 million light-years from Earth, is the first Milky Way-sized conglomeration of stars, planets, dust and gas found to be missing dark matter.
"This result does not fit in with the currently accepted cosmological models, which include dark matter," the leader behind the discovery and University of La Laguna researcher Sebastién Comerón said in a statement.
Dark matter is effectively invisible because it does not interact with light like the everyday matter that composes stars, planets, and us. Its presence can be inferred by its gravitational interactions, however. The existence of this shadowy substance was first posited when astronomers observed massive galaxies rotating so fast they would fly apart if it weren't for the gravitational influence of some unseen mass holding them together.
This fact resulted in scientists theorizing that all large galaxies are wrapped in an envelope of dark matter, and this has become an important assumption in the development of theories of galactic evolution. But the discovery of a galaxy that appears to haven no dark matter challenges that assumption.
Examining an anti-social relic galaxy
Considered a cosmic relic, NGC 1277 is unusual among galaxies because it has had little interaction with other surrounding galaxies. Galaxies like this are considered to be the remains of giant galaxies that existed in the early universe. As such, these relic galaxies are essential in helping astronomers to understand how the first galaxies formed.
To assist in this line of inquiry, Comerón and colleagues observed the relic galaxy NGC 1277 with an instrument called an integral field spectrograph. This allowed them to map the motion of the galaxy and determine its mass and how that mass is distributed.
This revealed that the distribution of NGC 1277's total mass — which should include dark matter — was the same as the distribution of the mass of its everyday matter contents, in other words, stars, dust, gas and planets. That means that within the galaxy's radius, there can't be a dark matter content any greater than 5%, but the findings are more consistent with a complete absence of dark matter in NGC 1277.
This is surprising, as the currently favored models of cosmic evolution including the standard model of cosmology, suggest NGC 1277 should be comprised of between 10% and 70% dark matter.
"This discrepancy between the observations and what we would expect is a puzzle, and maybe even a challenge for the standard model," team member and University of La Laguna researcher Ignacio Trujillo said.
Where did relic galaxy's dark matter go?
The scientists behind this revelation have a few ideas about why NGC 1277 is so deficient in dark matter.
"One is that the gravitational interaction with the surrounding medium within the galaxy cluster in which this galaxy is situated has stripped out the dark matter," team member and University of La Laguna researcher Anna Ferré-Mateu. "The other is that the dark matter was driven out of the system when the galaxy formed by the merging of protogalactic fragments, which gave rise to the relic galaxy."
The team isn't totally satisfied with either explanation and will, therefore, continue investigating NGC 1277 with the William Herschel Telescope (WHT) at the Roque de los Muchachos Observatory on the Canary Island of La Palma.
If these future investigations confirm this relic galaxy lacks the universe's most mysterious form of matter, the scientists think this won't challenge the existence of dark matter altogether. Conversely, the team believes it would challenge alternatives to dark matter models, so-called modified gravity theories.
"Although the dark matter in a specific galaxy can be lost, a modified law of gravity must be universal; it cannot have exceptions," said Trujillo. "So a galaxy without dark matter is a refutation of this type of alternative to dark matter."
Conclusive answers will have to wait, though, Comerón acknowledged. "The puzzle of how a massive galaxy can form without dark matter remains a puzzle," the scientist concluded.
The team's research is published in the journal Astronomy and Astrophysics.
Originally posted on Space.com.
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Robert Lea is a science journalist in the U.K. who specializes in science, space, physics, astronomy, astrophysics, cosmology, quantum mechanics and technology. Rob's articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University
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Cosmology & The Universe
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The James Webb Space Telescope, also known as the JWST, finally launched on December 25 for its journey 930,000 miles from Earth. This is the next generation that will replace the famous Hubble Space Telescope. Hubble has been capturing awesome photos for over 30 years, but it's time for something better. The JWST will be tasked with using its infrared sensors to explore some of the most distant and hard-to-see parts of the sky, helping with the search for exoplanets and with exploring the earliest days of the universe. So this seems like a good time to go over the most important scientific concepts that relate to space telescopes.Why Put a Telescope in Space?You can see all sorts of cool stuff, like nebulae and comets, from Earth with just some binoculars or a consumer telescope. But if you want research-quality images of distant galaxies, you have a problem: air. You might think air is transparent, but that’s only partially correct.Light is an electromagnetic wave, and it can have different wavelengths. People can only see a narrow range of wavelengths, from 380 nanometers (1 nm is 10-9 meter) to about 700. Our brains interpret the longer ones as red and the shorter ones as violet. These wavelengths are able to pass through the atmosphere without much of a decrease in brightness—so we can say the air is transparent to visible light.However, for other wavelengths of light that we can't detect with our eyes, the air is not so transparent. If we consider the infrared region of the electromagnetic spectrum (or wavelengths longer than red), then much of this light can be absorbed by both water vapor and carbon dioxide in the atmosphere. (Yes, this is the same thing that happens with global warming: When visible light hits the Earth’s surface, the temperature increases and it radiates infrared. Carbon dioxide in the air absorbs some of this infrared to further increase the atmosphere’s temperature. This can lead to bad things for humans.)This light absorption is also a particular problem for a ground-based infrared telescope. It would be like trying to look at the skies through clouds—it just wouldn’t work.One solution to this problem is to just put the telescope where there is no air: in space. (Of course, with every solution comes more challenges. In this case, you actually have to put a super-sensitive scientific instrument on a rocket and launch it, which is a bold move.)Why Does the JWST Look at Infrared Light?The JWST actually looks at two ranges of infrared light: the near infrared and mid-infrared. The near infrared is light with wavelengths very close to visible red light. It's the wavelength that your TV remote uses (if you can find it—it’s probably under the couch cushions).The mid-range infrared is often associated with heat, and that's mostly true. It turns out that everything produces light. Yes, you are sitting there making light. The wavelength of light that an object emits depends on its temperature. The hotter it gets, the shorter the wavelength of light. So, while you can’t see light emitted in the mid-infrared range, sometimes you can feel it.Try this: Turn on the stovetop in your kitchen, and hold your hand over a burner but don’t touch it. As the element warms up, it produces infrared light. You can't see this light, but when it hits your hand, you can feel it as heat.Although you can't see this kind of light, an infrared camera can. Check out this infrared image of me pouring a hot cup of coffee:Photograph: Rhett AllainThis is a false-color image. Basically, the camera mapped colors—from yellow to purple—onto different wavelengths of infrared light. The brighter yellow parts (like the pot of coffee) represent hotter things, and the darker purple parts are colder. Of course, reality is more complicated than this (you can also have reflected infrared light), but you get the idea.Great. But why does the JWST look at infrared light? The reason is the Doppler effect.You already know about the Doppler effect. You can hear it when a train or car moves past you at a high speed: The sound changes frequency because the source is first moving toward you, and then later away from you. The vehicle’s sound has a shorter wavelength, and therefore a higher pitch, while coming toward you, and then a longer wavelength and a lower pitch when it is moving away. (Here's an older post with more details).)It just so happens that you can also get a Doppler effect with light—but since the speed of light is super fast (3 x 108 m/s), the effect isn't noticeable in many situations. However, because of the expansion of the universe, just about all of the galaxies that we see from Earth are moving away from us. So to us, their light appears to have a longer wavelength. We call this a redshift, meaning the wavelengths are more red because they are longer. For very distant objects, this red shift is so large that the interesting stuff is in the infrared spectrum.There's actually another good reason to use infrared light for the JWST: It's difficult to get an unobstructed view of far-away celestial objects thanks to the gas and dust that are the detritus from old stars. These can scatter visible light more easily than they can infrared wavelengths. Essentially, infrared sensors are able to see through these clouds better than visible light telescopes can.Since the JWST is observing in the infrared spectrum, scientists will need everything to be as dark as possible around the telescope. That means that the telescope itself needs to be extremely cold to avoid emitting its own infrared radiation. This is one reason it has a sunshield. It will block the sunlight from the main instruments so they can stay cold. It will also help blot out excess light so the telescope can pick up the comparatively dim light from exoplanets as they orbit their much brighter host stars. (Otherwise, it would be like trying to see in the dark while someone shines a flashlight in your face.)How Does the JWST Look Back in Time?Light is a wave that travels really, really fast. In just a second, light could go around the circumference of the Earth more than seven times.When viewing celestial objects, we have to take into account the time it takes for light to travel from the object to our telescope or eyes. For example, light from the nearby Alpha Centauri star system takes 4.37 years to reach the Earth. So if you see it in the sky, you are literally looking 4.37 years into the past.(Actually, everything you see is in the past. You see the moon about 1.3 seconds in the past. When spotted closest to Earth, Mars is three minutes in the past.)The idea is for the JWST to be able to see more than 13 billion years into the past, to the point in the evolution of the universe when the first stars were being formed. That's just awesome, if you think about it.What Is a Lagrange Point?The Hubble Space Telescope is in low Earth orbit, which is nice because it has been possible for astronauts to service it when needed. But the JWST is going to be much farther away, at the L2 Lagrange point. But what the heck is a Lagrange point?Let's consider Hubble orbiting the Earth. For any object moving in a circle, there needs to be a centripetal force, or a force pulling it towards the circle’s center. If you swing a ball on a string around your head, the force pulling it towards the center is the tension in the string. For Hubble, this centripetal force is the gravitational force due to its interaction with the Earth.As an object moves farther away from Earth, the strength of this gravitational force decreases. So, if the telescope moved into a higher orbit (a larger circular radius), the centripetal force would decrease. In order to stay in a circular orbit, Hubble would have to take longer to orbit. (We would say it has a lower angular velocity.)The JWST orbits the sun instead of the Earth—but the same idea applies. The greater the orbital distance, the more time it takes to complete an orbit. But what if you want the JWST to be both further from the sun and complete a solar orbit in the same amount of time as the Earth? (To make it easier to control, the telescope would also have to remain in the same position relative to the Earth.) In order to get this to happen, you need to use a trick.That trick is a Lagrange point, a location in space where both the Earth and the sun exert a gravitational force in the same direction. An object at this point has two gravitational forces pulling on it to make it move in a circle. This allows it to orbit the sun with a higher angular velocity. It also keeps it at a fixed point relative to our planet.Illustration: Rhett AllainThere are five Lagrange points for the Earth-sun system. (If there is an L2 then there should at least be an L1—right?) The L2 Lagrange point is about 1.5 million kilometers from Earth, which is quite a bit farther than the 400 kilometers of low Earth orbit.Here are the four other Lagrange points for the Earth-sun system (not shown to scale):Illustration: Rhett AllainActually, the JWST won’t sit right at the L2 point. Instead, it will be in a very slow orbit. I know it seems bizarre that an object can orbit where there's nothing—but remember, the telescope won’t actually be orbiting the L2 point; it will be orbiting the sun. It will only look like it's orbiting L2 from our rotating reference point here on the Earth.Why Should Humans Spend Billions on the JWST?The telescope has cost around $8.8 billion dollars, plus another billion is planned for its operating costs. Some people might say it's just too much money. In fact, you could convince me that there are a significant number of projects for which so many billions would be better spent.But the JWST is still a good idea. It's an investment in basic science. Science, like art or literature or sports, is one of those things that make us human. Part of human nature is our curiosity about the universe around us. With the telescope, perhaps we will find out what the cosmos was like shortly after the Big Bang. We will be able to find more planets around other stars and even look for signatures of life. We’ll learn what the first galaxies were like, and how they formed. But I think the best thing that we can hope for from the James Webb Space Telescope is answers to the questions that haven't even been asked yet.More Great WIRED StoriesThe race to find “green” heliumYour rooftop garden could be a solar-powered farmThis new tech cuts through rock without grinding into itThe best Discord bots for your serverHow to guard against smishing attacks👁️ Explore AI like never before with our new database🏃🏽♀️ Want the best tools to get healthy? Check out our Gear team’s picks for the best fitness trackers, running gear (including shoes and socks), and best headphones
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Cosmology & The Universe
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Researchers from Montreal and India have detected a radio signal from a galaxy that's nearly nine billion light years away. According to their findings, the signal would have been emitted when the universe was just 4.9 billion years old – long before our own solar system was formed about 4.5 billion years ago. "It’s the equivalent to a look-back in time of 8.8 billion years," Arnab Chakraborty, the study's co-author and a post-doctoral researcher at McGill University, said in a news release. Published in the journal Monthly Notices of the Royal Astronomical Society, the study explains how researchers were able to capture the most distant signal ever in a specific radio wavelength known as the 21 centimetre line, which is created by hydrogen, providing them with a unique glimpse of the early universe. "A galaxy emits different kinds of radio signals," said Chakraborty, who studies cosmology in McGill's physics department. "Until now, it’s only been possible to capture this particular signal from a galaxy nearby, limiting our knowledge to those galaxies closer to Earth." The distant star-forming galaxy is known as SDSSJ0826+5630. The signal also enabled researchers to determine that the atomic mass of the galaxy's hydrogen gas content is nearly double the mass of the stars that are visible to us. Normally, signals like these from distant galaxies are too faint to detect with current radio telescopes, which often look like rows of large television satellite dishes. "But thanks to the help of a naturally occurring phenomenon called gravitational lensing, we can capture a faint signal from a record-breaking distance," Chakraborty said. "This will help us understand the composition of galaxies at much greater distances from Earth." Nirupam Roy is the study's co-author and an associate professor of physics at the Indian Institute of Science. "Gravitational lensing magnifies the signal coming from a distant object to help us peer into the early universe," Roy explained. "In this specific case, the signal is bent by the presence of another massive body, another galaxy, between the target and the observer. This effectively results in the magnification of the signal by a factor of 30, allowing the telescope to pick it up." With funding from McGill University and the Indian Institute of Science, the researchers utilized the Giant Metrewave Radio Telescope, which is an array of 30 maneuverable radio telescope dishes in western India's Maharashtra state. They say their findings demonstrate that it's possible to detect similar signals from faraway galaxies with the help of gravitational lensing, opening new opportunities to study the early universe with existing low-frequency radio telescopes.
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Cosmology & The Universe
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UC Santa Cruz astronomer Garth Illingworth, former Deputy Director of the Space Telescope Science Institute, has had a hell of a career.He's dedicated decades to the pursuit of finding and understanding the most distant galaxies, and was a leader on the team that built the Hubble Space Telescope. And before the Hubble was even in the sky, he'd already started to develop the James Webb Space Telescope (JWST) — yes, that James Webb Space Telescope, the one that's currently blowing Earthlings' minds on the daily with wildly beautiful images of our universe.While most of us look at those JWST pictures and just see pictures, Illingworth and his peers see all that and more: data. Over its few operational months, Webb has already offered an illuminating breadth of information — findings that have confirmed, confounded, and even contradicted existing theories about the cosmos. Curious about what that data means ourselves, we caught up with Illingworth to talk about space telescopes, far away worlds, and the ever evolving scientific process.This interview has been edited and condensed for length and clarity.Futurism: Your work has been extensive. Can you tell us a bit about your research and where it's taken you?Garth Illingworth: Sure, I'll give you the scientific framework. I'm an astronomer, and my key interests have been the early galaxies in the universe. Basically, we live 13.8 billion years after the Big Bang in a great, wonderful spiral galaxy, the Milky Way. But we had to get to this point.The very beginnings have intrigued me for a long time, ever since I saw the Hubble Deep Field back in 1995 — the first deep Hubble image of a blank part of the sky, which turned out not to be blank, but just absolutely packed with galaxies. That's what I've been working on for 25 or so years. Actually, back in the 80s, when I first started thinking about Webb, we hadn't even launched Hubble. Riccardo Giacconi, the director of the Space Telescope Science Institute at that time, said to me: "You guys really need to work on the next big telescope. Trust me, it's gonna take a long time."We had to do a rather interesting thing at that point. We had to project forward, even when we didn't know what Hubble was going to discover. We realized that we should go to longer wavelengths, we should really go into the infrared — we felt there were so many ways in which that could reveal aspects of the universe that Hubble would never reveal. It had to be a big telescope to work in the infrared. It had to be really cold, which meant it needs to be a long way from here. When we look back at the drawings now, these very simple-minded drawings, it's completely different from Webb, but in fact Webb operates and has the characteristics we thought of then. It's a big telescope, it's infrared, it's really cold, it's a hell of a long way away from us [laughs].Correct me if I'm wrong, but you and your team discovered what's believed to be the most distant and earliest galaxy that humans have yet seen, dating back to about 400 million years after the Big Bang.Yes. So, about seven or eight years ago, using Hubble, we amazingly found an object that was about 400 million, 450 million years after the Big Bang. I think if you'd asked me 10 years ago whether Hubble would have done that, I would have said no way. But it turned out that right at the limits of Hubble, we were able to find this early galaxy, and we could actually see it with the Spitzer Space Telescope — we could show there was a fuzzy blob there. That sat around as a real enigma for, like, seven years. We couldn't learn much about it, but it pointed to a very interesting change in the way galaxies were building up at early times. So the moment Webb got operational, the big question was: is this object unique? Or are there lots of others like that?Within four days of the Webb data being released in early-to-mid July, we already had a paper submitted to the preprint server. Actually, there were two groups to do it the same day, saying that we've discovered a couple of other objects like that one, and one of them was even further away. This was the sort of step that we had hoped that Webb would do — that it would expand our horizons into earlier times, and it did that incredibly quickly and very well.I think that goes back to the point about working on getting Hubble into space, but already thinking about the next thing. Now, it seems like the James Webb is happening very quickly — but it's because there's already such a large scientific foundation.Yeah, exactly. In the late 1990s, after the Hubble Deep Field came out, the goal of finding the first galaxies became the central goal for Webb. But right around that time, we discovered the first exoplanets. Dark energy was being discussed, and dark matter. There were so many things that Hubble was finding that we knew Webb would make a difference on — we just ended up having to wait 23 years.In July, when the first images were released, we had an hour where we were all seeing them for the first time. I was sitting in the same auditorium at Space Telescope where we had held the first meeting 33 years ago. It was a bit bizarre sitting there, looking around going God, this room looks pretty much the same as when we first talked about Webb, and here we're now seeing the first images coming in. And they're absolutely amazing.One particularly juicy takeaway from the James Webb is that some new data appears to contradict previous findings. Can you tell us more about that early galaxy that was a lot more massive than previously expected?Yes, sure. So this one, which we gave the name GNZ11 — not a very imaginative name, but astronomers are pretty boring when it comes to naming objects [laughs] — pointed to something unusual at these very early times.So in the in the first four days after the Webb images were released, we wrote these papers, and we realized that GNZ11 wasn't unique — there were others of these very bright, very luminous galaxies, which we interpreted as being unusually massive. Then, within weeks, there was another one even further back in time, closer to the Big Bang, that was still very massive. That has really been a surprise. We have to ask ourselves: is it really massive? Or does it have really unusual stars in it that are very bright, but not so much mass? We just don't know at this point, but Webb can answer these questions.What we need to do now is go in and look at those objects in more detail, see if we can learn more about what's actually in that galaxy. What the stars are like, whether there's lots of smaller stars that contribute a lot of mass. Theorists are now wondering: how do you build a galaxy like this so quickly, and does it have a black hole that's been building extremely rapidly in there as well? Are we been deceived? Galaxies can be pretty tricky. The universe can play games with you, even when you have Webb-quality data, but not enough of it.What do you think that a situation like this says about the scientific process itself?This is interesting, because I would say that in times past there was a very slow process of doing things. Data didn't come in very fast. We spent a lot of time working with it, sometimes you'd have to go back and get some more. Then, you know, the papers would come out, and we'd be pretty definitive. Papers come out, everybody thinks "oh, this is great." Then a year later, some new data comes along that goes "well, that was wrong." You have to recognize you can be wrong at any point, but when you're wrong, you learn new things.I think I've never felt particularly bad if people take the care to do as well as they can at the time, and then go back and revise things. Being wrong isn't bad, it's part of the process. And it's probably inevitable at this stage.Webb has been busy. Is there an upcoming target on its list that you're particularly excited to see and learn more about?Yes, the big image that was shown originally, of the cluster of galaxies, that was pointed to what I think will be extremely valuable in the future for learning more about galaxies. But I don't want to just emphasize the distant galaxies — exoplanets are going to be amazing, and then of course those star-forming regions like Carina and the Tarantula Nebula. Those look magnificent, but there's an incredible amount of science in those as well.And I would just say, you know, when I was sitting there watching the first images, I was just blown away by their beauty and the character there, the information. But one of the things I was thinking afterwards was: in that hour, I saw, like, six sets of data. I have to say, that's more data than I've ever seen from anything in any sort of reasonable time period in my whole life. Scientists are going to be working on those alone for ages, because there's so much information in those. And that was just a pathfinder — I mean, that was tens of hours of time, so we're gonna multiply that by 100, 1000 times every year.One of the things that I often get asked is: why does it matter? It's a lot of money. I've often thought about this, and I think the human race has a deep interest in our origins. We're interested in how we came about, how life came about. And then you really go, well, we're sitting on this little planet, how do the planets form? You can take this origins question, and that's what astronomy is really about. Webb, Hubble, these things are just origins machines. And what I really like about this, in so many ways, is that we're living in a very divisive environment, and this interest cuts across the lot of these political and otherwise areas beautifully.It's one of those places where we still have some common interests — which I hope we can expand in the future! Webb at least should contribute to that.More on the James Webb Space Telescope: Scientists Puzzled Because James Webb Is Seeing Stuff That Shouldn't Be There
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Cosmology & The Universe
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A brand new, detailed view of the universe that looks further back into space and time than ever before has been revealed.NASA is releasing a full set of images from its James Webb Space Telescope, showing what is said to be the "deepest" and most detailed picture of the cosmos to date.
This new view of the universe is possible because the Webb is huge - with a mirror more than twice the size of the previously-used Hubble.It is the largest and most powerful telescope ever sent into space.NASA revealing images that tell secrets of universe - live updates Scientists and engineers from three space agencies worked for 20 years to complete the £8.4bn telescope, which is designed to see objects using light that is invisible to the human eye.
One picture was released on Monday, when Joe Biden was given a presidential sneak peek of a galaxy-studded image from deep in the cosmos. More on Nasa James Webb Telescope live updates: NASA revealing images that tell secrets of universe The Hubble Space Telescope: What are its greatest hits? NASA reveals picture of distant universe taken by James Webb Space Telescope - but why is it a big deal? Today, the full set of extraordinary images is being unveiled in a live YouTube NASA broadcast. Only a handful of experts have seen them before today. Image: The first new image from James Webb Space Telescope a deep field cluster of distant galaxies. Pic: NASA/YouTube Each full-colour, high-resolution picture took weeks to render from raw telescope data.And they are promised to be four more galactic beauty shots from the telescope's initial outward gazes.The first shows a deep field cluster of distant galaxies, as they looked billions of years ago. Jane Rigby, who worked on the project, says this shows them from about the time the sun and earth formed.The image has a "sharpness and clarity" we've never had before, she says.Read more: Analysis: Why are these pictures such a big deal?The deepest view of the universe ever captured: NASA releases first image from new space telescope Image: NASA reveals images of the universe A partnership between NASA, the European Space Agency and the Canadian Space Agency, the Webb was launched on Christmas Day, 2021, and reached its destination in solar orbit nearly 1 million miles from Earth a month later.Once there, the telescope underwent a months-long process to unfurl all of its components, including a sun shield the size of a tennis court, and to align its mirrors and calibrate its instruments.The universe has been expanding for 13.8 billion years, meaning the light from the first stars and galaxies has been "stretched" from shorter visible wavelengths to longer infrared ones. This is what allows Webb to see the universe in unprecedented new detail.These pictures are the first of millions the new telescope will produce over its 20-year lifetime.Watch parties for the picture release took place all over the world including in the US, Canada, Israel, UK and Europe.
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Cosmology & The Universe
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The search for the missing gravitational signal
Every year, hundreds of thousands of pairs of black holes merge in a cosmic dance that emits gravitational waves in every direction. Since 2015, the large ground-based LIGO, Virgo and KAGRA interferometers have made it possible to detect these signals, although only about a hundred such events, an infinitesimal fraction of the total, have been observed.
Most of the waves remain 'indistinguishable,' superimposed and added together, creating a flat, diffuse background signal that scientists call the 'stochastic gravitational wave background' (SGWB).
New SISSA research, published in The Astrophysical Journal, proposes using a constellation of three or four space interferometers to map the flat and almost perfectly homogeneous background in a search for ripples. These small fluctuations, known to scientists as anisotropies, hold the information needed to understand the distribution of gravitational wave sources on the largest cosmological scale.
Researchers are convinced that next-generation detectors, such as the Einstein Telescope and the Laser Interferometer Space Antenna (LISA), will make direct measurement of the gravitational wave background possible in the foreseeable future.
"Measuring these background fluctuations, known more correctly as anisotropies, will however continue to be extremely difficult, as identifying them requires a very high level of angular resolution not possessed by current and next generation survey instruments," explains Giulia Capurri, a SISSA Ph.D. student and first author of the study.
Capurri, supervised by Carlo Baccigalupi and Andrea Lapi, has suggested that this problem could be overcome by means of a 'constellation' of three or four space interferometers in solar orbit and covering a distance approximating that between Earth and the Sun. With increasing separation, interferometers achieve better angular resolution, improving their ability to distinguish sources of gravitational waves.
"A constellation of space interferometers orbiting the Sun could enable us to see subtle fluctuations in the gravitational background signal, thus allowing us to extract valuable information about the distribution of black holes, neutron stars and all other sources of gravitational waves in the universe," says Capurri.
Following the success of the LISA project's space mission test, there are currently two proposals for the creation of space-based interferometer constellations: one European—the Big Bang Observatory (BBO), and one Japanese—the Deci-hertz Interferometer Gravitational-wave Observatory (DECIGO).
"This represents one of the earliest work to provide specific predictions of the size of the stochastic background of gravitational waves by a constellation of instruments orbiting the Sun. Together with further similar projects whose details will be published in due course, they will be crucial for developing an optimal design for future observational instruments that we hope will be built and commissioned in the coming decades," concludes Carlo Baccigalupi, professor of theoretical cosmology at SISSA.
In the era of multimessenger astronomy, which began with ground-based interferometers such as LIGO and Virgo, the gravitational-wave background could pave the way to a new understanding of the universe on the large scale, as has already happened with the cosmic microwave background.
More information: Giulia Capurri et al, Searching for Anisotropic Stochastic Gravitational-wave Backgrounds with Constellations of Space-based Interferometers, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/acaaa3
Journal information: Astrophysical Journal
Provided by International School of Advanced Studies (SISSA)
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Cosmology & The Universe
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In just a few days' time, NASA will intentionally crash a spacecraft into an asteroid at 15,000mph.Such a mission may evoke memories of a Hollywood disaster movie such as Armageddon or Deep Impact, but this is very much real and is actually part of the US space agency's first ever planetary defence test.Of course, there is no actual risk to Earth. This is merely an experiment that, if successful, could one day pave the way for protecting our planet from a catastrophic impact from space.The Double Asteroid Redirection Test (DART) was launched last November ahead of an almost year-long journey to crash into the small asteroid Dimorphos, which orbits a larger one called Didymos.Didymos and Dimorphos will make their closest approach to Earth in years in late September, passing at a distance of about 6.7 million miles (10.8 million kilometres) from our planet.The impact is due to take place on Monday (September 26) at 19:14 ET (00:14 BST Tuesday) and can be watched live on NASA TV and the agency's YouTube channel.Rome-based Virtual Telescope Project has also teamed up with several observatories in South Africa, and will be showing the target asteroid in real-time at the moment of the scheduled impact.The animation and graphic below shows how the mission will work, while MailOnline also explains the test's purpose and how it compares to a couple of the more famous asteroid-related disaster movies. Brace for impact: NASA's first ever 'planetary defence' spacecraft – sent to deflect an asteroid 6.8 million miles from Earth – is set to hit its target on Monday, September 26. The graphic above shows how the mission will work The spacecraft has captured images of its target double-asteroid system, which includes the asteroid it will crash into, called Dimorphos, the asteroid moonlet of Didymos The Double Asteroid Redirection Test was launched last November ahead of a year-long journey to crash into the small asteroid Dimorphos, which orbits a larger one called Didymos WHAT IS THE NASA DART MISSION? DART will be the world's first planetary defence test mission.It is heading for the small moonlet asteroid Dimorphos, which orbits a larger companion asteroid called Didymos.When it gets there it will be intentionally crashing into the asteroid to slightly change its orbit.While neither asteroid poses a threat to Earth, DART's kinetic impact will prove that a spacecraft can autonomously navigate to a target asteroid and kinetically impact it.Then, using Earth-based telescopes to measure the effects of the impact on the asteroid system, the mission will enhance modelling and predictive capabilities to help us better prepare for an actual asteroid threat should one ever be discovered.Astronomers say that anybody tuning it to watch the impact may well be able to spot changes in brightness of the asteroid as a result of the collision.That's if it is successful, of course, which wasn't quite the case in Deep Impact.The 1998 film depicts the attempts to prepare for and destroy a 7-mile (11 km) wide asteroid that is set to collide with Earth and cause a mass extinction.A team of astronauts are sent to land on the space rock and drill nuclear bombs deep beneath its surface, but rather than deflect the asteroid, when they're detonated they only split it in two.The smaller fragment goes on to hit Earth, creating a megatsunami that destroys much of the East Coast of the United States and also hits Europe and Africa, before the spacecraft and its crew that deployed the nuclear bombs sacrifice themselves by crashing into the bigger remnant of the asteroid and blowing it into smaller pieces.It is the latter technique that bears a similarity to the real-life DART mission, although there won't be any nuclear bombs involved.Part of the reason is that when the $325 million (£240 million) DART craft hits Dimorphos, the plan is for it to change the speed of the 'moonlet' by a fraction of a percentage, rather than obliterate it.Although the 525ft-wide space rock doesn't pose a danger to Earth, NASA wants to measure the asteroid's altered orbit caused by the collision.This demonstration of 'planetary defence' will inform future missions that could one day save Earth from a deadly asteroid impact.'This isn't going to destroy the asteroid. It's just going to give it a small nudge,' said mission official Nancy Chabot of Johns Hopkins Applied Physics Laboratory, which is managing the project.Dimorphos completes an orbit around Didymos every 11 hours and 55 minutes 'just like clockwork', she added.DART's goal is a crash that will slow Dimorphos down and cause it to fall closer toward the bigger asteroid, shaving 10 minutes off its orbit. The change in the orbital period will be measured by telescopes on Earth. The minimum change for the mission to be considered a success is 73 seconds.The DART technique could prove useful for altering the course of an asteroid years or decades before it bears down on Earth with the potential for catastrophe.NASA considers any near-Earth object 'potentially hazardous' if it comes within 0.05 astronomical units (4.6 million miles) and measures more than 460ft in diameter.More than 27,000 near-Earth asteroids have been catalogued but none currently pose a danger to our planet. Deep Impact (pictured) depicts the attempts to prepare for and destroy a 7-mile (11 km) wide asteroid that is set to collide with Earth and cause a mass extinction. A team of astronauts are sent to land on the space rock and drill nuclear bombs deep beneath its surface, but rather than deflect the comet, when they're detonated they only split it in two. The smaller fragment goes on to hit Earth, creating a megatsunamiWith Dimorphos, a small nudge 'would add up to a big change in its future position, and then the asteroid and the Earth wouldn't be on a collision course,' NASA said. The US space agency's Bobby Braun added during a media briefing earlier this month: 'This inaugural planetary test mission marks a major moment in human history.'For the first time ever we will measurably change the orbit of a celestial body in the universe.'Doing so has clear benefits in ensuring humanity's ability to deflect a potential threatening asteroid in the future.'Andrea Riley, DART programme executive at NASA HQ, said: 'The DART demonstration of technology to deflect an asteroid is one we believe is important to conduct before there is an actual need.'So while DART's target does not pose a threat to Earth, this mission and demonstration will give planetary defence experts more confidence that this is a viable mitigation technique should we ever discover [an asteroid that is].' An asteroid the size of Dimorphos could cause a continent-wide destruction on Earth, while the impact of one the size of the larger Didymos would be felt worldwide.One of the main reasons for the mission is that although astronomers know in a lot about the orbits of most of the 26,115 currently known near-Earth asteroids, they don't understand the density of the material the rocks are made of.This means they can only guess how the surface might behave upon impact, such as from a spacecraft. Pictured is the SpaceX Falcon 9 rocket which carried DART off the planet when it was launched in November 2021 DART will arrive at Dimorphos in two weeks' time, where it will deliberately smash into the asteroid at speeds of 15,000mph DIMORPHOS AND DIDYMOSDimorphos completes an orbit around Didymos every 11 hours and 55 minutes. It was discovered in 1996 by the Spacewatch survey at Kitt Peak.The sub-kilometre asteroid is classified as both a potentially hazardous asteroid and a near-Earth object.Orbiting Didymos is a 'moonlet' called Dimorphos, which was found in 2003. 'Asteroids are complicated, they look different, they've got boulders, they've got rocky paths, they've got smooth parts,' Chabot said. 'And so how exactly the DART spacecraft interacts with a real asteroid of this size and where it hits is one of the main factors for those models and also how that asteroid is put together. 'We know a lot of asteroids are maybe like rubble piles.'Scientists constantly search for asteroids and plot their courses to determine whether they could hit the planet.'Although there isn't a currently known asteroid that's on an impact course with the Earth, we do know that there is a large population of near-Earth asteroids out there,' said Lindley Johnson, NASA's Planetary Defense Officer.'The key to planetary defence is finding them well before they are an impact threat.'We don't want to be in a situation where an asteroid is headed towards Earth and then have to test this capability.'NASA is targeting the impact to be as nearly head-on as possible 'to cause the biggest deflection', but the 1,210lb spacecraft will not 'destroy' the asteroid. When DART spacecraft smashes into Dimorphos it will also have a witness in the form of an Italian cubesat called LICIACube, or the Light Italian Cubesat for Imaging of Asteroids.This is a 31lb (14 kg) micro-satellite that has hitched a ride on DART to the Didymos-Dimorphos binary asteroid system, before being deployed yesterday to give it 15 days to assume a safe position to observe the spacecraft's collision.'LICIACube will be released from the dispenser on one of DART's external panels, and will be guided (braking and rotating) to start its autonomous journey toward Dimorphos,' Elena Mazzotta Epifani, an astronomer at Italy's National Institute for Astrophysics (INAF) and a co-investigator on the LICIACube mission, told Space.com. 'The cubesat will point its cameras toward the asteroid system, but also to DART, and will probably take some pictures of it.'She added: 'Together, DART and LICIACube will analyse for the first time and with high detail the physical properties of a binary near-Earth asteroid, allowing us to investigate its nature and have hints on its formation and evolution.'LICIACube will obtain multiple images of the ejecta plume produced by the impact itself, of the DART impact [crater] size, as well as the non-impact hemisphere to help us to study the size and morphology of the crater and the effects on the surface properties in the surroundings.'Both Didymos and the smaller Dimorphos were discovered relatively recently; Didymos in 1996 and the smaller Dimorphos in 2003.The year it was discovered, Dimorphos came within 3.7 million miles of Earth — 15 times farther away than the moon. DEFLECTING AN ASTEROID WOULD REQUIRE 'MULTIPLE BUMPS', STUDY SAYSDeflecting an asteroid such as Bennu, which has a small chance of hitting Earth in about a century and a half, could require multiple small impacts from some sort of massive human-made deflection device, according to experts.Scientists in California have been firing projectiles at meteorites to simulate the best methods of altering the course of an asteroid so that it wouldn't hit Earth. According to the results so far, an asteroid like Bennu that is rich in carbon could need several small bumps to charge its course.Bennu, which is about a third of a mile wide, has a slightly greater chance of hitting Earth than previously thought, NASA revealed earlier this month.The space agency upgraded the risk of Bennu impacting Earth at some point over the next 300 years to one in 1,750.Bennu also has a one-in-2,700 chance of hitting Earth on the afternoon of September 24, 2182, according to the NASA study. Scientists have been seriously considering how to stop an asteroid from ever hitting Earth since the 1960s, but previous approaches have generally involved theories on how to blow the cosmic object into thousands of pieces.The problem with this is these pieces could potentially zoom towards Earth and present almost as dangerous and humanity-threatening an issue as the original asteroid. A more recent approach, called kinetic impact deflection (KID), involves firing something into space that more gently bumps the asteroid off course, away from Earth, while keeping it intact. Recent KID efforts were outlined at the 84th annual meeting of the Meteoritical Society held in Chicago this month and led by Dr George Flynn, a physicist at State University of New York, Plattsburgh. 'You might have to use multiple impacts,' Dr Flynn said in conversation with The New York Times. 'It [Bennu] may barely miss, but barely missing is enough.'Researchers have been working at NASA's Ames Vertical Gun Range, built in the 1960s during the Apollo era and based at Moffett Federal Airfield in California's Silicon Valley, for the recent KID experiments.They fired small, spherical aluminum projectiles at meteorites suspended by pieces of nylon string.The team used 32 meteorites – which are fragments of asteroids that have fallen to Earth from space – that were mostly purchased from private dealers. The tests have allowed them to work out at what point momentum from a human-made object fired towards an asteroid turns it into thousands of fragments, rather than knocking it off course as desired. 'If you break it into pieces, some of those pieces may still be on a collision course with Earth,' Dr Flynn said. Carbonaceous chondrite (C-type) asteroids, such as Bennu, are the most common in the solar system. They are darker than other asteroids due to the presence of carbon and are some of the most ancient objects in the solar system – dating back to its birth. According to the findings from experiments at AVGR, the type of asteroid being targeted (and how much carbon it has in it) may dictate how much momentum would be directed at it from any human-made KID device. From the experiments, the researchers found C-type meteorites could withstand only about one-sixth of the momentum that the other chondrites could withstand before shattering. '[C-type] asteroids are much more difficult to deflect without disruption than ordinary chondrite asteroids,' the experts concluded. 'These results indicate multiple successive impacts may be required to deflect rather than disrupt asteroids, particularly carbonaceous asteroids.'Therefore, around 160 years in the future – when Bennu is most likely to collide with Earth, according to NASA – a KID device would have to give it a series of gentle nudges to prevent it from breaking up and sending dangerous splinter fragments flying towards Earth.NASA's recent study about Bennu, published in the journal Icarus, did point out there is more than a 99.9 per cent probability Bennu will not smash into Earth over the next three centuries. 'Although the chances of it hitting Earth are very low, Bennu remains one of the two most hazardous known asteroids in our solar system, along with another asteroid called 1950 DA,' NASA said in a statement.
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Cosmology & The Universe
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A documentary film following the quest to understand the most mysterious objects in the universe. Now Available on Netflix and Apple TV! “Peter Galison's film does a superb job of conveying the life of science - the passion, the wonder, and the comradery forged by a group of people working together to fathom this strange cosmos we live in” – Alan Lightman, writer/physicist, MIT What can black holes teach us about the boundaries of knowledge? These holes in spacetime are the darkest objects and the brightest—the simplest and the most complex. With unprecedented access, Black Holes | The Edge of All We Know follows two powerhouse collaborations. Stephen Hawking anchors one, striving to show that black holes do not annihilate the past. Another group, working in the world’s highest altitude observatories, creates an earth-sized telescope to capture the first-ever image of a black hole. Interwoven with other dimensions of exploring black holes, these stories bring us to the pinnacle of humanity’s quest to understand the universe. For more information and updates about Black Holes | The Edge of All We Know, please join our email list: Please complete the form below
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Cosmology & The Universe
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For decades, scientists have been trying to solve a vexing problem about the weather in outer space: At unpredictable times, high-energy particles bombard the earth and objects outside the earth’s atmosphere with radiation that can endanger the lives of astronauts and destroy satellites’ electronic equipment. These flare-ups can even trigger showers of radiation strong enough to reach passengers in airplanes flying over the North Pole. Despite scientists’ best efforts, a clear pattern of how and when flare-ups will occur has remained enduringly difficult to identify. This week, in a paper in The Astrophysical Journal Letters, authors Luca Comisso and Lorenzo Sironi of Columbia’s Department of Astronomy and the Astrophysics Laboratory, have for the first time used supercomputers to simulate when and how high-energy particles are born in turbulent environments like that on the atmosphere of the sun. This new research paves the way for more accurate predictions of when dangerous bursts of these particles will occur. “This exciting new research will allow us to better predict the origin of solar energetic particles and improve forecasting models of space weather events, a key goal of NASA and other space agencies and governments around the globe,” Comisso said. Within the next couple of years, he added, NASA's Parker Solar Probe, the closest spacecraft to the sun, may be able to validate the paper’s findings by directly observing the predicted distibution of high-energy particles that are generated in the sun's outer atmosphere. In their paper, “Ion and Electron Acceleration in Fully Kinetic Plasma Turbulence,” Comisso and Sironi demonstrate that magnetic fields in the outer atmosphere of the sun can accelerate ions and electrons up to velocities close to the speed of light. The sun and other stars’ outer atmosphere consist of particles in a plasma state, a highly turbulent state distinct from liquid, gas, and solid states. Scientists have long believed that the sun’s plasma generates high-energy particles. But particles in plasma move so erratically and unpredictably that they have until now not been able to fully demonstrate how and when this occurs. Using supercomputers at Columbia, NASA, and the National Energy Research Scientific Computing Center, Comisso and Sironi created computer simulations that show the exact movements of electrons and ions in the sun’s plasma. These simulations mimic the atmospheric conditions on the sun, and provide the most extensive data gathered to-date on how and when high-energy particles will form. The research provides answers to questions that scientists have been investigating for at least 70 years: In 1949, the physicist Enrico Fermi began to investigate magnetic fields in outer space as a potential source of the high-energy particles (which he called cosmic rays) that were observed entering the earth’s atmosphere. Since then, scientists have suspected that the sun’s plasma is a major source of these particles, but definitively proving it has been difficult. Comisso and Sironi’s research, which was conducted with support from NASA and the National Science Foundation, has implications far beyond our own solar system. The vast majority of the observable matter in the universe is in a plasma state. Understanding how some of the particles that constitute plasma can be accelerated to high-energy levels is an important new research area since energetic particles are routinely observed not just around the sun but also in other environments across the universe, including the surroundings of black holes and neutron stars. While Comisso and Sironi’s new paper focuses on the sun, further simulations could be run in other contexts to understand how and when distant stars, black holes, and other entities in the universe will generate their own bursts of energy. “Our results center on the sun but can also be seen as a starting point to better understanding how high-energy particles are produced in more distant stars and around black holes,” Comisso said. “We’ve only scratched the surface of what supercomputer simulations can tell us about how these particles are born across the universe.”
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Cosmology & The Universe
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Space Updated on: September 6, 2022 / 7:56 PM / CBS News NASA releases stunning Webb Telescope images NASA releases stunning Webb Telescope images, previewing discoveries to come 03:29 NASA's highly sensitive James Webb Space Telescope has captured an extremely detailed image of thousands of never-before-seen young stars in a region known as the Tarantula Nebula.Located in the Large Magellanic Cloud, which is around 160,000 light years from Earth, the nebula, also known as stellar nursery 30 Doradus, is a region of very active star formation, according to NASA's Jet Propulsion Laboratory. NASA's mosaic image of the nebula covers an area of 340 light-years. Viewed with Webb's Near-Infrared Camera (NIRCam), the region resembles a burrowing tarantula's home. But it was actually named the Tarantula Nebula for its dusty filaments captured in previous telescope images. In this mosaic image stretching 340 light-years across, Webb's Near-Infrared Camera displays the Tarantula Nebula star-forming region in a new light, including tens of thousands of never-before-seen young stars that were previously shrouded in cosmic dust. Credit: NASA, ESA, CSA, STScI, Webb ERO Production Team The nebula is home to the hottest, most massive stars known to exist. And it's of major interest to astronomers because, unlike in our Milky Way, it is producing new stars at a "furious rate." Studying the nebula also offers astronomers a unique insight into our universe's past and how stars formed in the deep cosmic past. Though close to us, the chemical make-up of the nebula is similar to the gigantic, star-forming regions from when the universe was only a few billion years old, and star formation was at its peak — a period known as "cosmic noon." The sparkling blue stars seen in the image are responsible for creating the nebula's cavity — located right at the center of the NIRCam image — with their own radiation. "Only the densest surrounding areas of the nebula resist erosion by these stars' powerful stellar winds, forming pillars that appear to point back toward the cluster," said NASA. These pillars contain young stars called "protostars," which form in cocoons of dust. Webb's NIRCam caught one very young star still gathering mass in a cloud of dust and gas."Astronomers previously thought this star might be a bit older and already in the process of clearing out a bubble around itself," NASA said. "However, NIRSpec showed that the star was only just beginning to emerge from its pillar and still maintained an insulating cloud of dust around itself. Without Webb's high-resolution spectra at infrared wavelengths, this episode of star formation in action could not have been revealed." The heart of the Tarantula Nebula as seen in mid-infrared light by the James Webb Space Telescope. NASA, ESA, CSA, STScI, Webb ERO Production Team NASA also used its Mid-Infrared Instrument (MIRI), which is capable of penetrating deeper into the cosmos than a telescope using visible light, to look at the nebula. The MIRI revealed a very different side of the celestial structure and a "previously unseen cosmic environment," NASA said. "The hot stars fade, and the cooler gas and dust glow," NASA said. "Within the stellar nursery clouds, points of light indicate embedded protostars, still gaining mass." Webb, a joint project from NASA, the European Space Agency and the Canadian Space Agency, launched on Christmas Day last year, after more than 20 years of development, and in July it began delivering stunning new images of the cosmos."Webb has already begun revealing a universe never seen before, and is only getting started on rewriting the stellar creation story," NASA said.Correction: This story has been updated to note that Webb launched on Christmas Day but took several more months to begin sending images. In: James Webb Space Telescope galaxy NASA Natacha Larnaud Natacha Larnaud is a social TV producer for CBS News. Thanks for reading CBS NEWS. Create your free account or log in for more features. Please enter email address to continue Please enter valid email address to continue
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Cosmology & The Universe
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A binary star is a system of two gravitationally bound stars that orbit a common center of mass called a barycenter.
Stars in a binary system do not necessarily have the same mass, size or brightness. The larger star of a binary couple is called the primary star, while the smaller one is known as the secondary star or the companion star.
Related: What are star clusters?
Binary stars are double stars, but not all double stars are binary stars. This is because some double stars comprise two stars close enough in the sky over Earth to appear as a single point of light, but they are actually vastly separated in space and not part of a gravitationally bound binary system–these are called optical doubles.
Binary star FAQs
What is a binary star?
If a star is binary, it means that it's a system of two gravitationally bound stars orbiting a common center of mass.
Are binary stars rare?
No. It is estimated that around 85% of stars exist in binary star systems or systems with three or more stars. Single stars account for around 15% of all stars, but only 44% of stars that are similar to the sun are found with a binary partner, though this proportion is currently hotly debated.
Did the sun used to be a binary star?
Though the sun is currently a single star, research published in 2020 suggests that it could have once had a similar-size binary partner. Evidence for this theory comes from the fact that it would have been easier for binary stars to capture the Oort cloud, the shell of icy bodies that surrounds the outer limits of the solar system.
In 2018, a team of astronomers saw that the star HD 186302 is remarkably similar to the sun and could be our home star's stellar sibling or a "sun 2.0," with three other possible candidates highlighted.
How common are binary stars?
Unlike the sun, the vast majority of stars have a binary partner. The Australia Telescope National Facility estimates that up to 85% of all stars may exist in systems with two or three stars. So multistar systems are the norm, and binary systems are the most common multistar systems.
The chance of a star having a companion seems to diminish with its size, according to the book "Transiting Exoplanets" (Cambridge University Press, 2010). Around 75% of high-mass O-, B- and A-type stars seem to be found in multiple-star systems, roughly half of all known F- and G-type sunlike stars are found with a companion, and just 25% of small M-type red dwarf stars are found in multistar systems.
Binary star systems can also include systems containing a normal star and a stellar remnant, an object that forms when a star runs out of the fuel for nuclear fusion and collapses under its own gravity. These dense and compact star "corpses" can include white dwarfs, neutron stars and black holes. Especially ancient binary systems can contain two stellar remnants orbiting each other.
Who discovered binary stars?
The first observations of double stars were made in the early 17th century, but the binary nature of these objects was revealed later, according to the University of Oxford.
In 1767, astronomer and clergyman John Michell applied statistical principles to astronomy and studied the distribution of stars in the night sky. He determined that there were far more stars in pairs than could be accounted for if they were all randomly aligned, thus providing the first evidence for binary stars and star clusters.
In his 1781 catalog of 80 star systems, astronomer Christian Mayer proposed that "these stars could be small suns revolving around larger suns." However, astronomer and composer Frederick William Herschel was not convinced that double stars were composed of stars in physically bound systems, so he set about measuring the distances to these systems, using the principle of parallax, the observed displacement of an object caused by the change of the observer's point of view.
Herschel published his stellar catalog of 269 binary stars in 1782 and a second catalog of 434 more binaries in 1784. With the aid of his sister Caroline, Herschel observed the changes in the relative positions of these binary stars and published these observations in 1797. In 1803, he published a demonstration showing that these changes were the result of the stars existing in physical systems of mutual attraction, really bringing binary stars to the attention of the astronomical community.
Different types of binary star systems
The distances between stars in binary systems and their orbital periods differ considerably from binary to binary, and a system can be defined by these orbital distances. Stars in binary systems can have orbital separations equivalent to thousands of times the distance between Earth and the sun; these are predictably called "wide binaries," according to "Transiting Exoplanets." (Cambridge University Press, 2010).
There are also "close binaries." The stars in these systems are often so close that they can exchange material, with the star losing matter called the "donor star" and the star gathering that matter called the "accretor." (Accretion is the process by which matter is fed to a celestial body, like a star, white dwarf, neutron star or black hole.)
Detached binaries are binary stars that do not exchange material. Semidetached binaries are stars in which some material flows from one star to the other. And contact binaries have stars so close together, their gaseous envelopes overlap. These latter stars may be in the process of merging, according to the book "Introduction to the Sun and Stars" (Cambridge University Press, 2015).
Orbital distance and matter exchange are not the only ways to categorize binaries, however. According to the Australia Telescope National Facility, there are four types of binary star systems categorized by the methods used to detect them.
Visual binaries
A visual binary is a binary star system in which the stars can be individually seen as separate bodies in a telescope from Earth. For this reason, most visual binaries are star systems that are closer to Earth. They also tend to be wide binaries, as these factors make the stellar components easier to resolve.
Because of the distance between them, the stars in visual binaries do not usually interact via the exchange of material. The brighter star of a visual binary is given the suffix "A," while the dimmer component is assigned the suffix "B."
Spectroscopic binaries
When a binary system is too distant, or when the stars are too close together, the stellar bodies cannot be resolved separately by a telescope as with visual binaries. However, astronomers can use a phenomenon called Doppler shift to distinguish the stars in these binary systems, which are called spectroscopic binaries.
Doppler shift works because the wavelengths of light are shortened when a star is moving toward Earth, shifting it toward the blue end of the electromagnetic spectrum, while light from a star moving away from our planet has its wavelength stretched, or "redshifted."
A binary system emits light that is the combined light output, or "spectra," from both of its stellar components. If star A is moving away from Earth and star B is moving toward us, or vice versa, the individual spectra of these stars can be resolved by their red or blue shift. As observations of this binary continue and the stars proceed in their orbits, this situation will be reversed: As star A begins to move toward Earth, its light is then redshifted, and as star B begins to move away from our planet, its spectrum is blueshifted.
Spotting a spectroscopic binary relies heavily on several conditions being met. Most significantly, the orbital plane of the binary cannot be at a right angle to our line of sight, and the stars must not move across that line of sight because this stops the Doppler shift from being visible.
The chance of spotting a spectroscopic binary is reduced if the stars of a binary system are low-mass or if they are widely separated and thus have a long orbital period that lowers the probability of catching one star moving away from us and the other moving toward us. The chance of seeing a star binary as a spectroscopic binary is also lowered if one of the stars is dim and thus makes little contribution to the combined light from the system.
Despite these hindrances, most known binary star systems were spotted using their Doppler shifts.
Eclipsing binaries
Some stars demonstrate a periodic change in the magnitude of their brightness. This may be triggered when the star changes its intrinsic light output, as in the case of a pulsating variable star, or it could be because the star is a binary system viewed edge-on, meaning one star is periodically eclipsing the other. These are called eclipsing binaries.
Eclipsing binaries can also fit into the two previously mentioned categories and are often so close together that they exchange material.
Astrometric binaries
A companion star in a binary system can have an effect on its partner other than altering its light output. Though the two stars orbit a common center of mass, an unseen star can gravitationally "tug" on the other. This causes a periodic "wobble" in the visible star's motion over time. The precise measurement of a star's motion and position is called "astrometry," so binaries spotted in this way are known as astrometric binaries.
How do binary star systems evolve?
As mentioned above, in some binary systems, the stars are so close together that they exchange material. This mass transfer occurs when the radius of one star is not much smaller than the orbital separation between the stars.
This can proceed in several ways, according to "Introduction to the Sun and Stars." One mechanism, called Roche-lobe overflow, is particularly important. Each star in a binary system is surrounded by a theoretical pear-shaped volume called a Roche lobe, the size of which is determined by the mass of the star. When a donor star, usually a giant one, fills its Roche lobe, material flows from it through a gravitationally stable point called an inner Lagrangian point to the accretion star — often a white dwarf or other compact stellar remnant. As it enters the Roche lobe of the donor star, this matter still has angular material, so it can't go straight to the surface of the accretor. As such, it forms a stream of gas and dust on one side of the receiving star or an accretion disk from which it is gradually fed to the surface of the accretor star.
With a contact binary, both stars have filled their Roche lobes with the more massive star, sending material to its smaller companion but also sharing brightness and temperature.
Binary stars can also exchange material even if neither star fills its Roche lobe. This happens via stellar wind accretion, a process in which the accretor captures the stellar wind blowing from the donor star, usually a massive one.
The exchange of mass between stars can have a significant impact on the evolution of these systems and their stellar components. For instance, in a binary system with two main sequence stars, when the more massive star runs out of nuclear fuel and puffs out as a red giant filling its Roche lobe, it starts transferring matter to the other star. As the matter is transferred, the red giant loses mass, causing its Roche lobe to shrink and driving the mass transfer to proceed faster.
This can completely deplete the donor star's outer layers, leaving it as an exposed helium star on the path to becoming a white dwarf or a neutron star. This results in a binary system with a large main sequence star and a compact stellar remnant. This will not be the case forever, though. Eventually, after millions — or even billions — of years, the second star will also enter a red giant phase, filling its own Roche lobe, which causes it to start sending material to its white dwarf or neutron star companion.
Because of the incredible density of these stars, when matter falls onto them, it releases a huge amount of energy that can trigger thermonuclear reactions at the surface of that compact stellar remnant. In some cases, the accretion of matter from a red giant to a white dwarf can cause it to blast out a Type Ia supernova or can push it over the mass limit needed to transform it into a neutron star.
Do binary star systems host planets?
Extrasolar planets, or exoplanets, are planets that orbit stars other than the sun. Binary systems can possess exoplanets in stable orbits, some of which are closer to one star in the binary and thus orbit that star much as Earth orbits the sun, in what is called a circumstellar orbit. Other exoplanets in binary star systems have more unusual orbits, looping both of the stars in that system. Exoplanets that orbit an entire binary system in this way are said to possess "circumbinary orbits."
The first circumbinary planet discovered was PSR B1620-26 b, which was first hinted at in 1993 and was finally confirmed to exist in 2003. This planet's circumbinary orbit carries it around a white dwarf and a neutron star located around 12,400 light-years from Earth. The advanced stellar evolutionary status of the stellar occupants of this exotic system means it is believed to be around 12 billion years old, making PSR B1620-26 b potentially the oldest exoplanet discovered thus far and earning it the nickname Methuselah after the biblical figure who lived to a remarkably old age.
The first circumbinary planet discovered around a binary star young enough to still be burning hydrogen in its core, a so-called main sequence star," was discovered in 2011. Called Kepler-16 b, it orbits a main sequence star smaller than the sun as well as a red dwarf.
Astronomers aren't yet sure how existing in a binary star system would affect the habitability of a planet. In 2022, researchers looked at how habitable planets could possibly form in binary star systems. Focusing on a pair of young protostars still gathering the mass needed to trigger hydrogen fusion and become true stars in the binary system NGC 1333-IRAS2A, the team found that habitable planets could emerge around binaries but they would do so differently than those in single-star systems. This is because the complex behavior of young twin stars affects flattened clouds of planet-forming material around them called protoplanetary disks, distorting those disks with periodic outbursts of energy.
Also more complex is the calculation of where a habitable zone in or around a binary star system would be for an exoplanet. The habitable zone is the area around a star that is neither too hot nor too cold to allow for the existence of liquid water on an orbiting planet's surface — hence why it is often called the Goldilocks zone. This is tricky to estimate for binary star exoplanets because the distances between the planet and the stars change continuously — more so than for planets on elliptical orbits around a single star. This means the amount of starlight received by these exoplanets can vary substantially, and thus so can their surface temperatures.
In research conducted in 2007, scientists concluded that 50% to 60% of binary star systems could form planets with the necessary conditions needed to support life. With the Milky Way packed with 100 billion star systems, there are potentially many planets where life could exist under the glare of two "suns," similar to the fictional planet of Tatooine as strikingly depicted in "Star Wars."
Additional resources
A simulation shows how stars exchange material through a stable gravitational point via a process called Roche lobe overflow. Another simulation, created by NASA, shows what happens in a binary system that has evolved to the point at which both components are neutron stars.
Bibliography
Binary stars, Australia Telescope National Facility, [accessed 10/10/23], [https://www.atnf.csiro.au/outreach/education/senior/astrophysics/binary_intro.html]
Types of binary stars, Australia Telescope National Facility, [accessed 10/10/23], [https://www.atnf.csiro.au/outreach/education/senior/astrophysics/binary_types.html]
Multiple Star Systems, NASA, [accessed 10/10/23], [https://universe.nasa.gov/stars/multiple-star-systems/]
Binary star, Britannica, [accessed 10/10/23], [https://www.britannica.com/science/binary-star]
Binary Stars, Philosophy of Cosmology, Oxford University, [http://philosophy-of-cosmology.ox.ac.uk/binary-stars.html]
S.F. Green., M. H. Jones., Introduction to the sun and stars, Cambridge University Press, [2015], ISBN 978 1 107 49263 9
S. G. Ryan., A.J. Norton., Stellar evolution and nucleosynthesis, Cambridge University Press, [2010], ISBN 978 0 521 13320 3
C. A. Haswell., Transiting Exoplanets: Measuring the properties of planetary systems, Cambridge University Press, [2010], ISBN 978 0 521 13938 0
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Cosmology & The Universe
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Before stars or planets, before black holes and white dwarfs, before even atoms or rays of light, the Universe reverberated with something surprising – sound. This primordial hum moved at more than half the speed of light through a superheated plasma of baryons, photons, and dark matter.
It arose from a tug of war between ancient and powerful fundamental forces generating soundwaves in this electrically charged soup of particles. Then, just a few hundred thousand years into its existence, the plasma disappeared like a morning fog. The Universe fell suddenly, and profoundly silent.
Yet, it is still possible to pick up echos of these first soundwaves that spread out across our early Universe – if you know where to look. The ripples they created in the plasma have left a permanent imprint on the distribution of matter around the Universe. And they are also providing astronomers with clues about one of the deepest mysteries of our Universe today, the mysterious force known as dark energy.
The primordial soundwaves – also known as baryon acoustic oscillations (BAOs) – formed as the particles in the early Universe began to be pulled together by gravity.
"The gravitational pull of dark matter in the early Universe created 'potential wells,' pulling plasma inward," says Larissa Santos, a professor at the Center for Gravitation and Cosmology at the University of Yangzhou, China. The plasma, however, was so hot that it also created an opposing outward force. "Photons created radiation pressure that fought gravity, and pushed everything back out again. This fight created acoustic oscillations – sound waves."
BAOs burst outward from uncountable potential wells, forming expanding, concentric spheres of sound energy. They crisscrossed each other, sculpting the plasma into dazzlingly complex three-dimensional interference patterns.
Had a human somehow existed in the epoch of "baryon acoustic oscillations" (BAOs), they would have heard nothing. The sounds were around 47 octaves lower than the bottom note on a piano with enormous wavelengths of about 450,000 light years.
This incredibly deep, inaudible rumble travelled through a medium that even our most powerful telescopes is unable to penetrate. The deeper we look into the Universe, the further back into its history we see due to the time it takes for light to reach us. We can only see so far, however, as the electrical charges from unattached protons and electrons in these early stages of the Universe continuously scattered and diffused light, creating an impenetrably random glow. But BAOs created patterns in this medium which rippled outwards, and we can see evidence of these in the Universe today.
The Planck Space Telescope was able to pick up echos of BAOs from the early Universe and scientists have been able to translate them into audible frequencies, in the example below. The hum is composed of a low tone with higher overtones. The whoosing sound that can be heard is an artefact of the processing used to make the sound file.
Then, at about the age of 379,000 years old, the Universe cooled enough for protons and electrons to pair up and form the first neutral hydrogen atoms. The plasma disappeared, leaving the Universe suddenly and dramatically transparent to light. At the same moment, the battle between radiation and gravitation ended, BAOs ceased, and the Universe went silent.
The blast of light energy that now spread through the Universe was so powerful that it still jangles radio telescopes and tantalises physicists more than 13 billion years later as a signal known as cosmic microwave background radiation. The "CMB" is the oldest and most detailed visual record of the early Universe. Here too scientists can see a "fossil record" of the Universe's first sounds.
"We see them imprinted on the cosmic microwave background, and also in the large-scale structure of the Universe," says Santos, who is part of a new international radio telescopy project analysing modern echoes of that long-silenced song. "Their signature is found in a small excess in the number of pairs of galaxies separated by a fixed scale of 150 Megaparsecs — around 500 million light years."
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BAO signatures not only hint at what the early Universe sounded like, but also serve as a ruler for measuring the effects of yet another invisible phenomenon: dark energy.
Dark energy causes the Universe to expand. Its effects are everywhere, yet its nature is unknown. Studying the scale of BAO signatures at different distances from Earth tells a story about how dark energy's effects have changed over the history of the Universe.
"We call it a standard ruler," says Santos. "We have this fixed scale. We can know by how it appears to vary how the Universe was evolving through time."
She is part of the "Bingo" radio telescope project, currently under construction in the northeastern Brazilian state of Paraíba. Bingo (which stands for "BAOs from Integrated Neutral Gas Observations"), is attuned to the distinctive radiation signatures of hydrogen, the simplest, oldest, and the most abundant atom in the Universe.
The ripples created in the primordial plasma led to matter clumping together in ways that can still be seen in the way galaxies and stars are clustered (Credit: Nasa Goddard)
Hydrogen atoms release radiation with a 21-centimetre wavelength – invisible to human eyes, but detectable via radio telescope. This radiation from more distant clouds of hydrogen gets stretched by dark energy, increasing its observed wavelength here on Earth. The further it has travelled, the more stretched out it is.
"You choose a frequency for your radio telescope according to the epoch of the Universe that you want to measure," says Santos. Bingo is designed to map hydrogen distribution between one billion and four billion light years away – relatively close on the cosmic scale of space and time.
Bingo's two towering parabolic mirrors reflect this primordial radiation onto an array of 50 flared wave detectors known as "horns". The telescope's main moving part is the planet it rests on. The rotating Earth moves the telescope beneath the stars, scanning a strip of sky 15 degrees by 200 degrees.
Using subtle statistical calculations, Santos will analyse its data to locate millions of galaxies, examine their relative distances from one another, and dig deeper into how dark energy affected BAO patterns during that era.
"Bingo will look to the late Universe when dark energy already dominates the expansion. It's very complementary to other experiments," she says.
Many of those other experiments are already planned or underway.
Santos also hopes BAOs will reveal even more about the Universe's past, piercing the 379,000-year-thick wall of plasma
"Hydrogen intensity mapping can in principle measure anything in the Universe between present day and up to the CMB. That is a huge volume to explore," says Cynthia Chiang, a professor of physics who studies hydrogen density at McGill University in Montreal, Canada. "Bingo and other similar experiments look for the gas that lives inside galaxies. It is a tracer for where the matter is."
While instruments attuned to relatively close regions interest Chiang, she also craves answers about the rest of cosmic history.
"I take a very greedy approach to this," she says with a laugh. "I'm putting together an experiment that is tuned to frequencies that correspond to the 'Dark Ages'. That's the period immediately following the formation of the microwave background. We have never accessed any cosmology from this time period because it's very, very hard."
Between 250 and 350 million years elapsed between the "surface of last scattering" when the baryonic plasma gave way to the CMB, and the "cosmic dawn" when the first starlight shone out. BAOs left clouds of hydrogen clumped in wispy striations, liked an ebbing tide leaving ripples behind in the sand.
Before Chiang can access the 21-centimetre radiation from this era, she needs first to design experiments to filter out more recent signals from our own galaxy that could mask older data.
"This first experiment is not yet going to get at cosmology," she says. "The goal is to map the Milky Way emissions at these frequencies at a very high resolution so that we know what the sky looks like as a first pass. Then, hopefully, we can subtract that off and get to the cosmology.
"As the name suggests, in the Dark Ages, the Universe was a very dark and boring place. The signal you get then is almost a uniform 21-centimetre emission from this wall of hydrogen. But there are faint fluctuations in the brightness that correspond to the over-densities and under-densities. You get tiny cold and hot spots."
She says the CMB is like a still photograph capturing (in amazing detail) a pivotal moment in cosmological evolution. Mapping hydrogen density in the Dark Ages, though, would capture the hundreds of millions of years that immediately followed.
"It's a three-dimensional volume you can probe," says Chiang. "If you can measure the same sort of information as the CMB but reflected in hydrogen instead, you get tremendously more information, and you can potentially constrain cosmological parameters even more. If we get there, that would be amazing. But that's a very, very long road."
Chiang's planned experiments, alongside the Bingo telescope, add to a growing array of innovative observational instruments laying bare the history of BAOs, the large-scale structure of the Universe, and the invisible dark energy that drives galaxies apart.
"When we measure the sky, we measure everything," says Santos. "CMB, neutral hydrogen, galaxy point-sources, all this kind of stuff. We must be able to recognise what's a cosmological signal and what is everything else."
Santos also hopes BAOs will reveal even more about the Universe's past, piercing the 379,000-year-thick wall of plasma and providing data on the previous fraction of a second – the Universe's "inflationary epoch", during which most cosmologists think space was expanding at a rate faster than the speed of light.
Cosmological inflation is a widely trusted theory of how our Universe got from its tiny, hot, dense, original state to the cosmos we see today. The theory has gone through many incarnations, variations, and simulations. It makes many robust predictions that have been tested and verified, yet there is no direct evidence for it.
"Many, many inflationary theories have been already discarded by our observations," says Santos. "With the measurements we want to see, we can determine which theories agree best with that measurement and go from there."
Baryon acoustic oscillations only existed for a few hundred thousand years, but they helped create — and are helping scientists tell — the story of the invisible Universe from its first moment to its last.
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Cosmology & The Universe
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Carl Sagan, the acclaimed astronomer, astrophysicist and author who introduced a whole generation to the wonders of the heavens with his bestselling "Cosmos" science book and TV series and made saying the phrase "billions and billions" so much fun, is getting a new documentary feature on his prolific career courtesy of NatGeo and Seth MacFarlane.
Per Deadline (opens in new tab), the starbound legend of Carl Sagan will live on in a mind-expanding project being produced by National Geographic Documentary Films in alliance with Fuzzy Door's Seth MacFarlane and Erica Huggins, Emmy and Peabody winner Ann Druyan (Sagan's life partner). Academy Award nominee Nanette Burstein ("On the Ropes," "The Kid Stays in the Picture") is aboard as the film's director.
In addition to his many lifelong achievements, aptitude for teaching and inspiring voice in astronomy and cosmology, Sagan's bestselling novel "Contact" was adapted by director Robert Zemeckis ("Back to the Future," "Who Framed Roger Rabbit?") into the Academy Award-nominated 1997 sci-fi feature starring Jodie Foster and Matthew McConaughey. Sadly, Sagan passed away at the age of 62 in 1996, just prior to the Hollywood movie's theatrical release.
"Serving as an intimate and cinematic portrait of Sagan, the Untitled Carl Sagan Documentary will explore his love story with partner Ann Druyan and with science," said National Geographic Documentary Films in an official statement.
"The film will include exclusive audio recordings, archival clips and animation, along with interviews with his family, friends and colleagues," the statement continued. "With the full support of Sagan's family and friends, the film will present a fascinating look into the life and career of one of the world's most inspiring and revolutionizing scientists of our time."
This comprehensive Carl Sagan documentary currently has no release date scheduled, but will be offered exclusively on National Geographic channels and Disney+ when completed.
"Carl Sagan was a groundbreaking and revolutionary scientist who decoded the complexity of the cosmos and made planetary science accessible and relevant to audiences around the world," said Carolyn Bernstein, executive vice president of documentary films for National Geographic. "We are so excited to work with Nanette, Ann and Fuzzy Door to bring Sagan's pioneering work and compelling personal story to a new generation of admirers."
Producing partner Fuzzy Door is the creative shingle behind the hit shows "The Orville," "Family Guy" and "American Dad!" and also produced the Peabody award-winning reboot of Sagan's original "Cosmos" series, "Cosmos: A SpaceTime Odyssey," which accumulated 13 Emmy nominations and was hosted by noted astrophysicist and science personality Neil deGrasse Tyson.
"Carl's life is a multidimensional epic," said executive producer Ann Druyan. "He was a pathfinder in the sciences and a force in the culture, articulating the numinous wonder of a science-based sense of the sacred. He is one of the greatest awakeners in our history, and I feel that with Nanette, Fuzzy Door, Hungry Man and NatGeo, I now have the right partners to tell his thrilling story."
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Cosmology & The Universe
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(NEXSTAR) – A micrometeoroid caused “significant uncorrectable damage” to NASA’s $10 billion James Webb Telescope, a new report explains. While experts say the impact was small, it has prompted further investigation.At 21 feet, Webb’s gold-plated, flower-shaped mirror is the biggest and most sensitive ever sent into space. It’s comprised of 18 segments, one of which was smacked by the bigger than anticipated micrometeoroid in May. Micrometeoroids are fragments of asteroids that are usually smaller than a grain of sand, according to NASA.At the time, Paul Geithner, technical deputy project manager at NASA’s Goddard Space Flight Center explained it was known that Webb would have to survive the harsh environment of space, including micrometeoroids.In a newly released report, Webb’s commissioning team said that while the mirrors and sunshields on the telescope are “expected to slowly degrade from micrometeoroid impacts,” the impact to one specific segment, known as C3, “exceeded prelaunch expectations of damage for a single micrometeoroid.”Despite this, Webb’s team has determined the overall impact on the telescope is small. Engineers were able to realign Webb’s segments to adjust for the micrometeoroid’s damage. CDC warns virus that can cause seizures, death in infants circulating in multiple states Webb has been hit by at least six micrometeoroids since its December launch, equal to roughly one impact per month, matching expectations, according to their report. The damage to C3, however, has engineers investigating whether the impact was rare, meaning it could happen once every few years, or if Webb is “more susceptible to damage by micrometeoroids than pre-launch modeling predicted.”They are now working to determine how other micrometeoroids could impact Webb’s mirrors, how many of these asteroid fragments there are, and whether the telescope should be adjusted to spend less time pointing toward orbital motion, where it may be at greater risk of being struck by a micrometeoroid.Depending on its fuel usage, and expected degradation to the telescope, Webb could survive for more than 20 years, according to engineers. It launched into space in December from French Guiana in South America and reached its lookout point 1 million miles from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool.Webb’s first images, which gave us the deepest view into both time and distance that we’ve ever seen, were released last week. With one exception, the latest images showed parts of the universe seen by other telescopes. But Webb’s sheer power, distant location off Earth and use of the infrared light spectrum showed them in new light.This image released by NASA on Tuesday, July 12, 2022, shows the Southern Ring Nebula for the first time in mid-infrared light. It is a hot, dense white dwarf star, according to NASA. (NASA, ESA, CSA, STScI via AP)This image provided by NASA on Tuesday, July 12, 2022, shows Stephan’s Quintet, a visual grouping of five galaxies captured by the Webb Telescope’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI). This mosaic was constructed from almost 1,000 separate image files, according to NASA. (NASA, ESA, CSA, and STScI via AP)This image provided by NASA on Monday, July 11, 2022, shows galaxy cluster SMACS 0723, captured by the James Webb Space Telescope. The telescope is designed to peer back so far that scientists can get a glimpse of the dawn of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus. (NASA/ESA/CSA/STScI via AP)This image released by NASA on Tuesday, July 12, 2022, shows the bright star at the center of NGC 3132, the Southern Ring Nebula, for the first time in near-infrared light. (NASA, ESA, CSA, STScI via AP)FILE – In this April 13, 2017 photo provided by NASA, technicians lift the mirror of the James Webb Space Telescope using a crane at the Goddard Space Flight Center in Greenbelt, Md. The telescope is designed to peer back so far that scientists will get a glimpse of the dawn of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus. (Laura Betz/NASA via AP, File)This image released by NASA on Tuesday, July 12, 2022, combined the capabilities of the James Webb Space Telescope’s two cameras to create a never-before-seen view of a star-forming region in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI), this combined image reveals previously invisible areas of star birth. (NASA, ESA, CSA, STScI via AP)This combo of images released by NASA on Tuesday, July 12, 2022, shows a side-by-side comparison of observations of the Southern Ring Nebula in near-infrared light, at left, and mid-infrared light, at right, from the Webb Telescope. (NASA, ESA, CSA, and STScI via AP)FILE – This 2015 artist’s rendering provided by Northrop Grumman via NASA shows the James Webb Space Telescope. The telescope is designed to peer back so far that scientists will get a glimpse of the dawn of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus. (Northrop Grumman/NASA via AP, File)This image provided by NASA on Tuesday, July 12, 2022, shows Stephan’s Quintet, a visual grouping of five galaxies captured by the Webb Telescope’s Mid-Infrared Instrument (MIRI). (NASA, ESA, CSA, and STScI via AP)The plan is to use the telescope to peer back so far that scientists will get a glimpse of the early days of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus.The Associated Press contributed to this report. For the latest news, weather, sports, and streaming video, head to The Hill.
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Cosmology & The Universe
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By Eleonora Di Valentino - Postdoctoral Researcher of Astrophysics, University of ManchesterNo matter how elegant your theory is, experimental data will have the last word. Observations of the retrograde motion of the planets were fundamental to the Copernican revolution, in which the sun replaced Earth at the centre of the solar system. And the unusual orbit of Mercury provided a spectacular confirmation of the theory of general relativity. In fact, our entire understanding of the universe is built on observed, unexpected anomalies. Our paper, published in Nature Astronomy, has come to a conclusion that may unleash a crisis in cosmology – if confirmed. We show that the shape of the universe may actually be curved rather than flat, as previously thought – with a probability larger than 99%. In a curved universe, no matter which direction you travel in, you will end up at the starting point – just like on a sphere. Though the universe has four dimensions, including time.The result was based on recent measurements of the Cosmic Microwave Background, the light left over from the Big Bang, collected by the Planck Satellite. According to Albert Einstein’s theory of general relativity, mass warps space and time around it. As a result, light rays take an apparent turn around a massive object rather than travelling in a straight line – an effect known as gravitational lensing.There is much more such lensing in the Planck data than there should be, which means the universe could contain more dark matter – an invisible and unknown substance – than we think. In our study, we showed that a closed universe can provide a physical explanation to this effect, because it is able to host a lot more dark matter than a flat universe. Such a universe is perfectly compatible with general relativity. The Cosmic Microwave Background temperature fluctuations from the seven-year WMAP data over the sky. - Image Credit: NASA/WMAP Major headacheNot all cosmologists are convinced by a closed universe though – previous studies have suggested the cosmos is indeed flat. And if a spherical universe is a solution to the lensing anomaly, then we have to deal with several significant consequences. First of all, we have to revise a fundamental cornerstone of cosmology – the theory of cosmological inflation. Inflation describes the first instants after the Big Bang, predicting a period of exponential expansion for the primordial universe.The theory was developed over the past 40 years to explain why distant parts of the universe look the same and have the same temperature, when they are too far apart to ever have been in contact. Inflation solves the problem because it means that far-flung regions of the universe would once have been connected. But the period of rapid expansion that hurled these regions apart is also thought to have also brought the universe to flatness with exquisite precision.If the universe is closed, standard inflation is in trouble. And that means we lose our standard explanation for why the universe has the structure it has. Possible shapes of the universe: top one is curved and closed, as suggested in the new study - Image Credit: NASA via Wikimedia Commons Once we assume that the universe is curved, the Planck data is essentially in disagreement with all other datasets. This all boils down to a real crisis for cosmology, as we say in our paper. For these reasons, cosmologists are cautious – and many of them prefer to attribute the results to a statistical fluke that will resolve when new data from future experiments are available.Could we be wrong?It is certainly possible that we turn out to be wrong. But there is one main reason, in our opinion, why this anomaly should not be merely discarded. In particle physics, a discovery should reach an accuracy of at least five “sigmas” to be accepted by the community. Here we are slightly above three sigmas, so we are clearly below this acceptance level. But while the standard model of particle physics is based on known and proven physics, the standard cosmological model is based on unknown physics. At the moment, the physical evidence for the three pillars of cosmology – dark matter, dark energy (which causes the universe to expand at an accelerated rate) and inflation – comes solely from cosmology. Their existence can explain many astrophysical observations.But they are not expected either in the standard model of particle physics that governs the universe on the smallest scales or in the theory of general relativity that operates on the large scales. Instead, these substances belong to the area of unknown physics. Nobody has ever seen either dark matter, dark energy or inflation – in the laboratory or elsewhere.So while an anomaly in particle physics can be regarded as a hint that we may need to invent completely new physics, an anomaly in cosmology should be regarded as the only way we have to shed light on completely unknown physics.Therefore, the most interesting result of our paper is not that the universe appears to be curved rather than flat, but the fact that it may force us to rearrange the pieces of the cosmic puzzle in a completely different way.Source: The Conversation If you enjoy our selection of content please consider following Universal-Sci on social media:
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Cosmology & The Universe
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To those of us who aren't astronomers, it's hard to see what the big deal is. An image of points of light, coloured blobs and spirals of galaxies of the kind we're familiar with.
But in fact, this image is something very different indeed.Compared to the previous picture of this region of space captured by the Hubble Space Telescope, the image from the James Webb Space Telescope (JWST) is jam-packed with galaxies. Twitter Due to your consent preferences, you’re not able to view this. Open Privacy Options These are new objects, likely never seen before through any telescope. This new view of the universe is possible because the Webb is huge - with a mirror more than twice the size of the Hubble.
But as well as that, Webb sees infrared light. More on Nasa A dying star and a 'cosmic dance': Ancient galaxies revealed in never-seen-before telescope pictures James Webb Telescope live updates: NASA reveals images that tell secrets of universe The Hubble Space Telescope: What are its greatest hits? The universe has been expanding for 13.8 billion years, meaning the light from the first stars and galaxies has been "stretched" from shorter visible wavelengths to longer infrared ones.This is what allows Webb to see the universe in unprecedented new detail.That detail may be pretty to us, but it's a rich seam of new data for astronomers, astrophysicists and cosmologists.But, this image excites those experts for another reason - it's looking further back in space and time than ever before. Image: First image from James Webb Space Telescope It's not just a picture of any random bit of space. At its centre, you can see the hint of a spherical-like object traced out by curved and distorted galaxies.This is a gravitational lens, a natural, if mind-boggling, feature of the universe predicted by Einstein's theory of general relativity.A huge cluster of galaxies in the centre of the image is so massive that is distorting space, bending the light that travels through it and magnifying the objects behind it. Please use Chrome browser for a more accessible video player Watch timelapse of telescope build Hiding in this image, brought into crude focus by this gravitational lens, are quite probably the oldest galaxies we've ever seen.Their light, when analysed carefully by other instruments on JWST, will give new insights into the earliest time in the universe just a few hundred million years after the Big Bang.It's an image that's a window into a new way of understanding how the universe we live in came to be.And it's just the first of millions that this new telescope will produce over its 20-year lifetime.
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Cosmology & The Universe
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It all began with a wobble.Some 20 light-years away from Earth, which is quite close on a cosmic scale, scientists noticed a star acting a little funny. Something almost imperceptibly small appeared to be tugging on it, forcing it to "wobble" in its stellar neighborhood, as astronomers would whimsically say.Aha, an exoplanet.This was a Jupiter doppelganger, to be exact, with a mass about twice the size of our solar system's own gas giant, an orbit rounds its star every 284 days and a position that falls slightly closer to its star than Venus floats from the sun. And from here, an already invigorating achievement, the discovery team decided to take things to the next level -- especially because the wobbly star at hand exists as part of a binary star system, meaning it's one of two stars orbiting around each other. After careful analysis, these researchers hit the jackpot. They used their faint signal of a foreign world to develop what they deem the first ever blueprint of a complete, 3D structure of not just a binary star system orbit, but one with a planet roaming within. And before we go any further, yes, you can check out a mesmerizing, visual representation of those schematics right below. (More technical details can be found in a paper published Thursday in The Astronomical Journal).
OK, cool, what can we do with this?As Earthlings, we're used to living alongside our lone sun, but when calculating star populations across the universe, it seems that our planet's personal space heater is a minority. Generally, stars prefer traveling in duos, trios, and even quartets. "Since most stars are in binary or multiple systems, being able to understand systems such as this one will help us understand planet formation in general," Salvador Curiel, of the National Autonomous University of Mexico and first author of the new paper, said in a statement. Data we get from our own corner of the cosmos isn't really enough to understand some of the greater rules for how planets are made, or how they evolve. It's always better to have a wider sample size.Returning to the binary star system we're looking at with Curiel's 3D diagram, this particular pair, called GJ 896AD, is importantly made up of two red dwarfs -- aka the smallest, coolest kind of star on the main sequence and most common stellar genre in the Milky Way. And what better place to start decoding the secrets of multi-star systems than with the most prevalent kind in our galaxy?From above a planet about twice the size of Jupiter, this artist's conception shows the star that planet is orbiting and that star's binary companion in the distance. Sophia Dagnello, NRAO/AUI/NSF To paint a picture of what this faraway realm looks like, the researchers say that the larger of the two stars, which is the one orbited by the exoplanet, has about 44% the mass of our sun. The smaller one is only about 17% the mass of our sun. So small, so cute. Oh, and they orbit each other once every 229 Earth years, while the super-Jupiter follows an orbit that's inclined roughly 148 degrees from the two stars' paths."There are alternate theories for the formation mechanism, and more data can possibly indicate which is most likely," Joel Sanchez-Bermudez of UNAM and author of the study, said in the release. "In particular, current models indicate that such a large planet is very unlikely as a companion to such a small star, so maybe those models need to be adjusted."Thank you, Very Long Baseline ArrayThe driving force behind this astronomical development -- metaphorically and literally -- is the National Science Foundation's Very Long Baseline Array. This science mechanism consists of a network of ten observing stations spread across the US, each one holding a 25-meter radio antenna dish and control building. Basically, the stations individually capture deep space information, then connect-the-dots to compile a super clear representation of what's going on out there in the cosmos. In Northern California sits one of the identical ten antennas of the Very Long Baseline Array. NRAO/AUI/NSF For this study, of GJ896AB, the scientists collected optical observations spanning a staggering range of time: 1941 to 2017. They then called on VLBA observations taken between 2006 and 2011, plus made new VLBA observations in 2020. Slap all of that together and you get an awesome measurement of GJ896AB's positions over time, which can be combined into something like a stop-motion conception of how this star system looks."The planet moves around the main star in the opposite direction to that of the secondary star around the main star," said Gisela Ortiz-León, of the Max Planck Institute for Radio Astronomy and author of the study. "This is the first time that such dynamical structure has been observed in a planet associated with a compact binary system that presumably was formed in the same protoplanetary disk.""We can do much more work like this with the planned Next Generation VLA," Amy Mioduszewski, of the National Radio Astronomy Observatory and author of the paper, said. "With it, we may be able to find planets as small as the Earth."
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Cosmology & The Universe
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A high-resolution illustration of the Nancy Grace Roman Space Telescope against a starry background. ... [+] NASA’s Goddard Space Flight Center No sooner did the Webb telescope flash its spectacular first images across the world, do some science and even find time to get struck by something than NASA is planning the next space telescope. NASA announced today that it has contracted SpaceX to launch its new Roman Space Telescope. Now in development, it will go skywards between October 2026 and May 2027 from Launch Complex 39A at NASA’s Kennedy Space Center in Florida atop a SpaceX Falcon Heavy rocket. SpaceX will make $255 million from the contract. What is the Roman Space Telescope?
In some ways the Roman Space Telescope is a successor to Hubble, with a primary mirror measuring 2.4-meters—the same size as Hubble’s. However, Roman will have a huge field of view, with its wide-angle lens able to see an area of the sky about 100 times larger than what Hubble can see. It’s expected to cost between $3.2 billion and $3.9 billion. A SpaceX Falcon Heavy rocket will launch NASA's Roman Space Telescope in 2026/2027. Getty Images What will the Roman Space Telescope do?
Roman will undertake a “Galactic Exoplanet Survey” designed to find Earth-like exoplanets and also help astronomers understand how the universe expands. Its wide-angle lens will help it map the Milky Way and other galaxies 100 times faster than Hubble and allow astronomers to see the environments around galaxies in the early universe. It will be able to create Roman ultra-deep fields far more extensive than either the Hubble ultra-deep fields or even the first Webb deep field. It will also investigate dark matter and dark energy—modern astronomy’s greatest mysteries—and look for Earth-like exoplanets. In fact, Roman is expected to find thousands of exoplanets, including more “rogue” planets than there are stars in the Milky Way—at least 100 billion! It will do that using an incredible technique called gravitational microlensing. What is microlensing?
Microlensing is what Roman is all about—it’s what makes it a unique and special space telescope. It will allow astronomers to find new types of exoplanets thousands of light years from Earth orbiting stars near the center of the Milky Way. The technique is similar to how Albert Einstein’s theory of general relativity was proven during a total solar eclipse in 1919. Its incredible sensitivity will allow it to detect when the gravity of stars and planets bend and magnify the light coming from stars that pass behind them from the telescope’s point of view. Portrait of American astronomer Nancy Grace Roman (1925 - 2018) at NASA's Goddard Space Flight ... [+] Center in Greenbelt, Maryland, early 1970s. She is known as the 'mother of Hubble' for her role in the planning of the Hubble Space Telescope. (Photo by NASA/Interim Archives/Getty Images) Getty Images Who is the Roman Space Telescope named after?
Dr. Nancy Grace Roman, an American astronomer who spent 21 years at NASA, died in 2018 . She’s known as a the “mother of Hubble” and recognised for making the concept of the space telescope a reality. In the mid-1960s she headed-up a committee of astronomers and engineers to work on ideas for a space telescope and convinced both NASA and the U.S. Congress that a powerful space telescope should be a science priority.
The Roman Space Telescope was formerly known as the Wide Field InfraRed Survey Telescope (WFIRST). Wishing you clear skies and wide eyes.
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Cosmology & The Universe
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Stephen Hawking's interstellar call to save Earth is coming soon to children's bookshelves.
Stephen Hawking (1942-2018), the famed physicist best known for his studies of the universe's past and future, was also concerned about the future of planet Earth. Daughter Lucy Hawking adapted his 2018 message about our planet into the new children's book "You and the Universe" (Random House, 2024) releasing March 26, 2024. You can preorder it now.
"'You and the Universe' is an imaginative and inclusive book which brings my father's extraordinary work in science to life for readers of all ages, beautifully illustrated by artist Xin Li,” Lucy Hawking said in a statement.
"The combination of my father's words with Xin's stunning visuals will captivate the very youngest scientists, and spark their curiosity about the universe we inhabit by sharing the wonder and delight of the cosmos — and remind us all why life on Earth is so unique and precious."
You and the Universe | $19.99 on Amazon
Stephen Hawking's message for Earthlings is rendered into a new children's book, with the help of his daughter, Lucy, and illustrator Xin Li. Children will learn how to protect Earth while being there for one another.
Hawking spent his career studying cosmology, or the universe as a whole, with most of his work performed at the University of Cambridge. In 1963, he was given two years to live after being diagnosed with a motor neuron disease (known popularly as Lou Gehrig's disease after the New York Yankees baseball player who also had it, or more properly as amyotrophic lateral sclerosis.)
Hawking outlived this dire diagnosis by decades, continuing to perform research using a wheelchair and a specially adapted computer that transmitted his words by voice. He also advocated for disability inclusion, and for protecting Earth from humanity. In 2017, for example, he warned that the damage to our planet induced by human-made "climate change" was reaching a tipping point that could see our planet turn into a hothouse world such as Venus.
The new book is based upon a 2018 partnership Hawking's family had with the European Space Agency, along with the Greek composer Vangelis ("Blade Runner", "Chariots of Fire", "Cosmos: A Personal Voyage".) The message used words adapted from Hawking's book for adults, "Brief Answers to the Big Questions" (Bantam, 2018), set to music by Vangelis.
Around the time that Hawking was being laid to rest in Westminster Abbey, ESA transmitted a message Hawking had for Earth to our nearest black hole, 1A 0620-00, using the Cebreros station in Madrid that usually communicates with deep-space European missions.
With permission, ESA then re-adapted the message for public release for Earth Day (April 22) in 2020 via YouTube, using images from satellites and space launches to illustrate the physicist's words.
"I have spent my life travelling across the universe inside my mind. Through theoretical physics, I have sought to answer some of the great questions. But there are other challenges, other big questions which must be answered," part of Hawking's message states.
Hawking said that finding solutions for renewable energy and slowing down climate change will require a "new generation who are interested, engaged and with an understanding of science."
"We are all time travellers journeying together into the future," he added. "But let us work together to make that future a place we want to visit. Be brave, be determined, overcome the odds. It can be done."
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Cosmology & The Universe
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The Universe is a hologram: Stephen Hawking's final theory, explained by his closest collaborator
In 1998 Stephen Hawking took me on as his PhD student “to work on a quantum theory of the Big Bang”. What started out as a doctoral project evolved over some 20 years into an intense collaboration that ended only with his passing five years ago on March 14, 2018.
The enigma at the centre of our research throughout this period was how the Big Bang could have created conditions so perfectly hospitable to life. What are we to make of this mysterious appearance of intent?
Such questions take physics far out of its comfort zone. Yet this was exactly where Hawking liked to venture. After all, the prospect – or hope – of being able to crack the riddle of cosmic design drove much of his work.
Our shared scientific quest meant that inevitably we grew close. Being around him, one could not fail to be influenced by his determination and by his epistemic optimism that we could tackle these mystifying cosmic questions.
He made us feel as if we were writing our own creation story, which, in a sense, we did.
The idea that time had a beginning in a Big Bang was championed in the early 1930s by the Belgian priest-astronomer Georges Lemaître. Albert Einstein famously rejected it, because it reminded him of Christian dogma. But eventually Hawking and Roger Penrose proved Lemaître right.
Ever since, the origin of time has been the cornerstone, but also the Achilles’ heel of Big Bang cosmology. For how exactly could time pop into existence?
Hawking’s final theory of the Big Bang provides a bold and surprising answer. It envisages the Universe as a holographic projection.
In a familiar hologram, a third dimension of space emerges from the lines and scribbles on a screen. In the cosmos-as-hologram idea, which has become the talk of the town among theoretical physicists, it is the dimension of time that can be holographically encoded.
Read more:
- Where did the Big Bang take place?
- If energy can’t be created, where did it come from in the first place?
Stephen liked to visualise this idea in a disk-like image of the kind shown above. The outer circle depicts a timeless hologram consisting of countless entangled qubits.
The disk shows the evolution of an expanding Universe that projects down from this. The origin of the Universe lies at the centre of the disk and it expands outward in the radial direction.
It is as if there is a code operating on the entangled qubits that brings about the Universe and this is what we perceive as the flow of time.
Crucially, by taking a fuzzier view of the hologram, one ventures farther back in time, toward the interior of the disk. It is like zooming out. Eventually, however, one runs out of bits. This is the origin of time, according to our theory.
There can be nothing before the Big Bang, because the past that holographically emerges doesn’t extend further back.
These insights yield a new twist on the riddle of cosmic design. The early Hawking sought to describe the origin of the Universe as a quantum creation event.
In those days, Stephen strove to give a fundamentally causal explanation of the origin of the Universe: why, not how. But the discovery of holography advances a radically different view of cosmogenesis.
It says that physics itself fades away when we journey back into the Big Bang. The Big Bang emerges from holography not so much as the beginning of time but more as the beginning of laws.
What is left, then, of the age-old question of the ultimate cause of the Big Bang? It would seem to evaporate, the late Hawking held. Not the laws as such but their capacity to change and transmute has the final word.
Dr Thomas Hertog is a Belgian cosmologist at KU Leuven University and author of On The Origin Of Time: Stephen Hawking’s Final Theory, is published 4 April 2023 (£20, Penguin). It is available for pre-order at Penguin and Amazon UK
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Science & Astronomy An artist's interpretation of utilizing a wormhole to travel through space, Thorne kick-started a serious discussion among scientists about whether or wormhole travel is possible. (Image credit: NASA) This article was originally published at The Conversation. The publication contributed the article to Space.com's Expert Voices: Op-Ed & Insights.Mario Borunda, Associate Professor of Physics, Oklahoma State UniversityThe closest star to Earth is Proxima Centauri. It is about 4.25 light-years away, or about 25 trillion miles (40 trillion km). The fastest ever spacecraft, the now- in-space Parker Solar Probe will reach a top speed of 450,000 mph. It would take just 20 seconds to go from Los Angeles to New York City at that speed, but it would take the solar probe about 6,633 years to reach Earth’s nearest neighboring solar system.If humanity ever wants to travel easily between stars, people will need to go faster than light. But so far, faster-than-light travel is possible only in science fiction.In Issac Asimov’s Foundation series, humanity can travel from planet to planet, star to star or across the universe using jump drives. As a kid, I read as many of those stories as I could get my hands on. I am now a theoretical physicist and study nanotechnology, but I am still fascinated by the ways humanity could one day travel in space.Some characters – like the astronauts in the movies “Interstellar” and “Thor” – use wormholes to travel between solar systems in seconds. Another approach – familiar to “Star Trek” fans – is warp drive technology. Warp drives are theoretically possible if still far-fetched technology. Two recent papers made headlines in March when researchers claimed to have overcome one of the many challenges that stand between the theory of warp drives and reality.But how do these theoretical warp drives really work? And will humans be making the jump to warp speed anytime soon?This 2-dimensional representation shows the flat, unwarped bubble of spacetime in the center where a warp drive would sit surrounded by compressed spacetime to the right (downward curve) and expanded spacetime to the left (upward curve). (Image credit: AllenMcC/Wikimedia Commons)Compression and expansionPhysicists’ current understanding of spacetime comes from Albert Einstein’s theory of General Relativity. General Relativity states that space and time are fused and that nothing can travel faster than the speed of light. General relativity also describes how mass and energy warp spacetime – hefty objects like stars and black holes curve spacetime around them. This curvature is what you feel as gravity and why many spacefaring heroes worry about “getting stuck in” or “falling into” a gravity well. Early science fiction writers John Campbell and Asimov saw this warping as a way to skirt the speed limit.What if a starship could compress space in front of it while expanding spacetime behind it? “Star Trek” took this idea and named it the warp drive.In 1994, Miguel Alcubierre, a Mexican theoretical physicist, showed that compressing spacetime in front of the spaceship while expanding it behind was mathematically possible within the laws of General Relativity. So, what does that mean? Imagine the distance between two points is 10 meters (33 feet). If you are standing at point A and can travel one meter per second, it would take 10 seconds to get to point B. However, let’s say you could somehow compress the space between you and point B so that the interval is now just one meter. Then, moving through spacetime at your maximum speed of one meter per second, you would be able to reach point B in about one second. In theory, this approach does not contradict the laws of relativity since you are not moving faster than light in the space around you. Alcubierre showed that the warp drive from “Star Trek” was in fact theoretically possible.Proxima Centauri here we come, right? Unfortunately, Alcubierre’s method of compressing spacetime had one problem: it requires negative energy or negative mass.This 2–dimensional representation shows how positive mass curves spacetime (left side, blue earth) and negative mass curves spacetime in an opposite direction (right side, red earth). (Image credit: Tokamac/Wikimedia Commons, CC BY-SA)A negative energy problemAlcubierre’s warp drive would work by creating a bubble of flat spacetime around the spaceship and curving spacetime around that bubble to reduce distances. The warp drive would require either negative mass – a theorized type of matter – or a ring of negative energy density to work. Physicists have never observed negative mass, so that leaves negative energy as the only option.To create negative energy, a warp drive would use a huge amount of mass to create an imbalance between particles and antiparticles. For example, if an electron and an antielectron appear near the warp drive, one of the particles would get trapped by the mass and this results in an imbalance. This imbalance results in negative energy density. Alcubierre’s warp drive would use this negative energy to create the spacetime bubble.But for a warp drive to generate enough negative energy, you would need a lot of matter. Alcubierre estimated that a warp drive with a 100-meter bubble would require the mass of the entire visible universe.In 1999, physicist Chris Van Den Broeck showed that expanding the volume inside the bubble but keeping the surface area constant would reduce the energy requirements significantly, to just about the mass of the sun. A significant improvement, but still far beyond all practical possibilities.A sci-fi future?Two recent papers – one by Alexey Bobrick and Gianni Martire and another by Erik Lentz – provide solutions that seem to bring warp drives closer to reality.Bobrick and Martire realized that by modifying spacetime within the bubble in a certain way, they could remove the need to use negative energy. This solution, though, does not produce a warp drive that can go faster than light.[Over 100,000 readers rely on The Conversation’s newsletter to understand the world. Sign up today.]Independently, Lentz also proposed a solution that does not require negative energy. He used a different geometric approach to solve the equations of General Relativity, and by doing so, he found that a warp drive wouldn’t need to use negative energy. Lentz’s solution would allow the bubble to travel faster than the speed of light.It is essential to point out that these exciting developments are mathematical models. As a physicist, I won’t fully trust models until we have experimental proof. Yet, the science of warp drives is coming into view. As a science fiction fan, I welcome all this innovative thinking. In the words of Captain Picard, things are only impossible until they are not.This article is republished from The Conversation under a Creative Commons license. Read the original article.Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook and Twitter. The views expressed are those of the author and do not necessarily reflect the views of the publisher. Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.
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Cosmology & The Universe
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Astronomers carry out largest ever cosmological computer simulation
An international team of astronomers has carried out what is believed to be the largest ever cosmological computer simulation, tracking not only dark but also ordinary matter (such as planets, stars and galaxies), giving us a glimpse into how our universe may have evolved.
The FLAMINGO simulations calculate the evolution of all components of the universe—ordinary matter, dark matter, and dark energy—according to the laws of physics. As the simulation progresses, virtual galaxies and clusters of galaxies emerge. Three papers have been published in Monthly Notices of the Royal Astronomical Society: one describing the methods, another presenting the simulations and the third examining how well the simulations reproduce the large-scale structure of the universe.
Facilities such as the Euclid Space Telescope recently launched by the European Space Agency (ESA) and NASA's JWST collect impressive amounts of data on galaxies, quasars, and stars. Simulations such as FLAMINGO play a key role in the scientific interpretation of the data by connecting predictions from theories of our universe to the observed data.
According to the theory, the properties of our entire universe are set by a few numbers called 'cosmological parameters' (six of them in the simplest version of the theory). The values of these parameters can be measured very precisely in various ways.
One of these methods relies on the properties of the cosmic microwave background (CMB), a faint background glow left over from the early universe. However, these values do not match those measured by other techniques that rely on the way in which the gravitational force of galaxies bends light (lensing). These 'tensions' could signal the demise of the standard model of cosmology—the cold dark matter model.
The computer simulations may be able to reveal the cause of these tensions because they can inform scientists about possible biases (systematic errors) in the measurements. If none of these prove sufficient to explain away the tensions, the theory will be in real trouble.
So far, the computer simulations used to compare to the observations only track cold dark matter. "Although the dark matter dominates gravity, the contribution of ordinary matter can no longer be neglected," says research leader Joop Schaye (Leiden University), "since that contribution could be similar to the deviations between the models and the observations."
The first results show that both neutrinos and ordinary matter are essential for making accurate predictions, but do not eliminate the tensions between the different cosmological observations.
Simulations that also track ordinary, baryonic matter (also known as baryonic matter) are much more challenging and require much more computing power. This is because ordinary matter—which makes up only sixteen percent of all matter in the universe—feels not only gravity but also gas pressure, which can cause matter to be blown out of galaxies by active black holes and supernovae far into intergalactic space.
The strength of these intergalactic winds depends on explosions in the interstellar medium and is very difficult to predict. On top of this, the contribution of neutrinos, subatomic particles of very small but not precisely known mass, is also important but their motion has not been simulated so far.
The astronomers have completed a series of computer simulations tracking structure formation in dark matter, ordinary matter, and neutrinos. Ph.D. student Roi Kugel (Leiden University) explains, "The effect of galactic winds was calibrated using machine learning, by comparing the predictions of lots of different simulations of relatively small volumes with the observed masses of galaxies and the distribution of gas in clusters of galaxies."
The researchers simulated the model that best describes the calibration observations with a supercomputer in different cosmic volumes and at different resolutions. In addition, they varied the parameters of the model, including the strength of galactic winds, the mass of neutrinos, and the cosmological parameters in simulations of slightly smaller but still large volumes.
The largest simulation uses 300 billion resolution elements (particles with the mass of a small galaxy) in a cubic volume with edges of ten billion light years. This is believed to be the largest cosmological computer simulation with ordinary matter ever completed. Matthieu Schaller, of Leiden University, said, "To make this simulation possible, we developed a new code, SWIFT, which efficiently distributes the computational work over 30 thousand CPUs."
The FLAMINGO simulations open a new virtual window on the universe that will help make the most of cosmological observations. In addition, the large amount of (virtual) data creates opportunities to make new theoretical discoveries and to test new data analysis techniques, including machine learning.
Using machine learning, astronomers can then make predictions for random virtual universes. By comparing these with large-scale structure observations, they can measure the values of cosmological parameters. Moreover, they can measure the corresponding uncertainties by comparing with observations that constrain the effect of galactic winds.
More information: Joop Schaye et al, The FLAMINGO project: cosmological hydrodynamical simulations for large-scale structure and galaxy cluster surveys, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad2419
Roi Kugel et al, FLAMINGO: Calibrating large cosmological hydrodynamical simulations with machine learning, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad2540
Ian G McCarthy et al, The FLAMINGO project: revisiting the S8 tension and the role of baryonic physics, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad3107
Journal information: Monthly Notices of the Royal Astronomical Society
Provided by Royal Astronomical Society
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Cosmology & The Universe
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The Gaia mission has revealed a "goldmine" of new information on cosmic objects as it continues to create the most comprehensive stellar catalog ever compiled.
The new release, known as Gaia's focused product release (FPR), contains over half a million new faint stars, more than 380 new gravitationally lensed quasars and the positions of over 150,000 solar system asteroids.
Containing data on 1.8 billion stars, the comprehensive map of the Milky Way galaxy and its cosmic backyard being created by Gaia will allow scientists to continue to dig deep into our cosmic history. The new release fills in some important gaps in that map as it forms.
According to Gaia's operators, the European Space Agency (ESA), the new data provides exciting and unexpected science and findings that go far beyond what the space telescope was initially designed to discover.
The new trove of research builds upon the third Data Release (DR3) from Gaia published in June 2022. Though comprehensive, DR3 contained gaps in the sky not yet mapped by the space telescope and overlooked some faint stars that didn't shine as bright as their surrounding stellar companions.
Particular examples of this are globular clusters, which are some of the oldest objects in the universe with densely clustered cores of bright stars that can overwhelm telescopes attempting to study them.
More than filling in unexplored regions in Gaia's cosmic map
Part of the new release from the star surveyor space telescope focused on the Milky Way's most massive globular star cluster, Omega Centauri, which contains around 10 million stars — making its core the most crowded region of space the telescope has studied thus far.
To patch these gaps, ESA astronomers focused Gaia on Omega Centauri, which, at just around 15,800 light-years away, is relatively close to Earth and can be used as a proxy for the study of other clusters of this type.
"In Omega Centauri, we discovered over half a million new stars Gaia hadn't seen before — from just one cluster!" research lead author and member of the Gaia collaboration Katja Weingrill said in a statement.
Instead of focusing on single stars within the cluster, something Gaia specializes in, the space telescope observed Omega Centauri with a special mode that allows Gaia to look at a wider patch of sky around the core of the globular cluster each time it came into view. Thus, the new observations also helped test this special mode and Gaia's instruments.
"We didn't expect to ever use it for science, which makes this result even more exciting," Weingrill added.
Though the new data has helped fill in some unexplored regions in Gaia's 3D map of the Milky Way, it is of interest to scientists in itself, helping better model the Omega Centauri globular cluster.
"Our data allowed us to detect stars that are too close together to be properly measured in Gaia's regular pipeline," research co-author and Gaia Collaboration member Alexey Mints added. "With the new data, we can study the cluster's structure, how the constituent stars are distributed, how they're moving, and more, creating a complete large-scale map of Omega Centauri. It's using Gaia to its full potential — we've deployed this amazing cosmic tool at maximum power."
In this regard, the new data release of the FPR is just a taster of what is to come in Gaia Data Release 4 (DR4), with the space telescope currently exploring a further eight regions of the Milky Way in a similar fashion to how it investigated Omega Centauri. As a result, by studying cosmic building blocks like Omega Centauri, DR4 could help reveal details about our galaxy, such as its true age, the precise location of its center and if it has collided with other galaxies throughout its history.
Gaia as a gravitational lens hunter
Even though it wasn't designed to study the universe on a wider scale, the FPR releases from Gaia show it could be uncovering things that are vital to understanding the cosmos as a whole, such as its evolution and its precise age.
One of the ways Gaia could have an impact on cosmology is by finding what astronomers call gravitational lenses, objects of great density like star clusters that can be used to amplify light from distant background sources like ancient galaxies.
This works thanks to an effect predicted by Einstein's theory of general relativity, which suggests that objects of mass "warp" the very fabric of spacetime; the greater the mass, the more extreme the warping is. When a warping object lies between Earth and a distant source, light from that distant source passes the intermediate object and is 'bent' on its way towards us. The amount of deflection depends on how close the light's path comes to the mass source. As a result, light from the same source arrives at Earth at different times and a single object can appear at multiple points in the same image.
This effect can amplify that distant source, allowing objects that would usually be too distant and faint to be seen. The James Webb Space Telescope is currently using this phenomenon to great effect to observe some of the universe's oldest galaxies. Gaia can assist in this by finding more gravitationally lensed objects — particularly quasars, the active hearts of galaxies powered by feeding black holes. Spotting lensed quasars isn't easy because the repeated images caused by gravitational lensing can often cluster together, making a single object appear smeared in images and leading to it being misidentified.
"Gaia is a real lens-seeker. Thanks to Gaia, we've found that some of the objects we see aren't simply stars, even though they look like them," research co-author and Gaia collaboration member Christine Ducourant said. "They're actually really distant lensed quasars — extremely bright, energetic galactic cores powered by black holes.
"We now present 381 solid candidates for lensed quasars, including 50 that we deem highly likely: A goldmine for cosmologists and the largest set of candidates ever released at once."
These candidates were selected from a list of possible quasar candidates, some of which were included in DR3, with five of the lensed objects appearing to be rare formations called "Einstein crosses." These occur when light from a single object appears at multiple places in the same image from the shape of a cross. In 2021, Gaia spotted 12 of these Einstein crosses.
"The great thing about Gaia is that it looks everywhere, so we can find lenses without needing to know where to look," research co-author Gaia collaboration member Laurent Galluccio said. "With this data release, Gaia is the first mission to achieve an all-sky survey of gravitational lenses at high resolution."
This demonstrates how Gaia could team up with the ESA's dark matter and dark energy detective Euclid, launched in July 2023, to help investigate these mysterious aspects of the universe that comprise an estimated 95% of its content. The new releases from Gaia also show the space telescope also has utility much closer to home.
Tracking asteroids, red giants, and more with Gaia
Part of the new Gaia releases show details of 156,823 of the asteroids around Earth that were identified in DR3, better pinpointing their locations and constraining their orbits with 20 times more precision than previous observations.
The ESA space telescope did this by observing the space rocks for almost twice as long as it had previously. The ESA predicts that the forthcoming Gaia data dump DR4 will double the number of asteroids seen by the space telescope as well as increasing the number of solar system bodies observed by Gaia by including comets and even satellites around Earth.
The new Gaia releases also include observations of the dynamics of over 10,000 binary red giant stars, making this the largest collection of such stellar objects ever collated, and signals from gas and dust that drift between stars in the disk of the Milky Way.
"Although its key focus is as a star surveyor, Gaia is exploring everything from the rocky bodies of the solar system to multiply imaged quasars lying billions of light-years away, far beyond the edges of the Milky Way," ESA Gaia project scientist Timo Prusti said. "The mission is providing a truly unique insight into the Universe and the objects within it, and we're really making the most of its broad, all-sky perspective on the skies around us."
The FPR from Gaia takes the form of five papers published on Tuesday, Oct. 10:
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Cosmology & The Universe
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In the upcoming 50 years, humankind will attempt to answer fundamental questions about the universe and the fundamentals of our existence: Is there life on exoplanets? Is there extraterrestrial life in our solar system? Where has all the antimatter in the universe gone? - Robin Smith explains what we can expectBy Robin Smith - Lecturer in Physics, Sheffield Hallam University In 1900, so the story goes, prominent physicist Lord Kelvin addressed the British Association for the Advancement of Science with these words: “There is nothing new to be discovered in physics now.”How wrong he was. The following century completely turned physics on its head. A huge number of theoretical and experimental discoveries have transformed our understanding of the universe, and our place within it.Don’t expect the next century to be any different. The universe has many mysteries that still remain to be uncovered – and new technologies will help us to solve them over the next 50 years.The first concerns the fundamentals of our existence. Physics predicts that the Big Bang produced equal amounts of the matter you are made of and something called antimatter. Most particles of matter have an antimatter twin, identical but with the opposite electric charge. When the two meet, they annihilate each other, with all their energy converted into light.Read more: Explainer: what is antimatter?But the universe today is made almost entirely out of matter. So where has all the antimatter gone?The Large Hadron Collider (LHC) has offered some insight into this question. It collides protons at unimaginable speeds, creating heavy particles of matter and antimatter that decay into lighter particles, several of which had never been seen before.The LHC has shown that matter and antimatter decay at slightly different rates. This goes part – but nowhere near all – of the way to explaining why we see an asymmetry in nature.The problem is that compared to the precision physicists are used to, the LHC is like playing table tennis with a tennis racquet. As protons are made up of smaller particles, when they collide their innards get sprayed all over the place, making it much harder to spot new particles among the debris. This makes it difficult to accurately measure their properties for further clues to why so much antimatter has disappeared.Three new colliders will change the game in the coming decades. Chief among them is the Future Circular Collider (FCC) – a 100km tunnel encircling Geneva, which will use the 27km LHC as a slipway. Instead of protons, the colliders will smash together electrons and their antiparticles, positrons, at much higher speeds than the LHC could achieve. Unlike protons, electrons and positrons are indivisible – so we’ll know exactly what we’re colliding. We’ll also be able to vary the energy at which the two collide, to produce specific antimatter particles, and measure their properties – particularly the way they decay – much more accurately.These investigations could reveal entirely new physics. One possibility is that the disappearance of antimatter could be related to the existence of dark matter – the thus far undetectable particles that make up a whopping 85% of mass in the universe. The absence of antimatter and prevalence of dark matter probably owe themselves to the conditions present during the Big Bang, so these experiments probe right into the origins of our existence.Its impossible to predict how as-yet hidden discoveries from collider experiments will change our lives. But the last time we looked at the world through a more powerful magnifying glass, we discovered subatomic particles and the world of quantum mechanics – which we’re currently harnessing to revolutionise computing, medicine and energy production.Alone no more?Just as much remains to be discovered on the cosmic scale – not least the age-old question of whether we’re alone in the universe. Despite the recent discovery of liquid water on Mars, there is not yet any evidence of microbial life. Even if found, the planet’s harsh environment means it would be incredibly primitive.The search for life on planets in other star systems has so far not borne fruit. But the upcoming James Webb Space Telescope, launching in 2021, will revolutionise the way that we detect habitable exoplanets.Unlike previous telescopes, which measure the dip in a star’s light as an orbiting planet passes in front of it, James Webb will use an instrument called a coronagraph to block the light from a star entering the telescope. This works in much the same way as using your hand to block sunlight from entering your eyes. The technique will allow the telescope to directly observe small planets that would ordinarily be overwhelmed by the bright glare of the star they orbit. Not only will the James Webb telescope be able to detect new planets, but it will also be able to determine if they’re able to support life. When the light from a star reaches a planet’s atmosphere, certain wavelengths are absorbed, leaving gaps in the reflected spectrum. Much like a barcode, these gaps provide a signature for the atoms and molecules of which the planet’s atmosphere is made.The telescope will be able to read these “barcodes” to detect whether a planet’s atmosphere has the necessary conditions for life. In 50 years’ time, we could have targets for future interstellar space missions to determine what, or who, may live there.Closer to home, Jupiter’s moon, Europa, has been identified as somewhere in our own solar system that could harbour life. Despite its cold temperature (−220°C), gravitational forces from the ultra-massive planet it orbits may slosh water beneath the surface around sufficiently to prevent it from freezing, making it a possible home for microbial or even aquatic life.A new mission called Europa Clipper, set for launch in 2025, will confirm whether a sub-surface ocean exists and identify a suitable landing site for a subsequent mission. It will also observe jets of liquid water fired out from the planet’s icy surface to see if any organic molecules are present.Whether its the tiniest building blocks of our existence or the vastness of space, the universe still holds a number of mysteries about its workings and our place within it. It will not give up its secrets easily – but the chances are that the universe will look fundamentally different in 50 years’ time.Source: The Conversation If you enjoy our selection of content please consider following Universal-Sci on social media:
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Cosmology & The Universe
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How did the universe come to be? The prevailing theory is everything that is began with the Big Bang. In a nutshell, the theory suggests everything, everywhere, all at once suddenly burst to life. The caveat being everything and everywhere prior to the Big Bang is fairly hard to conceptualize. The Big Bang theory is currently the best model we have for the birth of our universe. Astrophysicists have shown the theory explains, fairly comprehensively, phenomena we've observed in space over decades, like lingering background radiation and elemental abundances. It's a robust framework that gives us a pretty good idea of how the cosmos came into being some 13.8 billion years ago. But with the flurry of pre-print papers and popular science articles about the James Webb Space Telescope's first images, old, erroneous claims the Big Bang never happened at all are circulating on social media and in the press in recent weeks. One scientist has claimed the JWST images are inspiring "panic among cosmologists," AKA the scientists who study the origins of the universe.This is simply not true. The JWST has not provided evidence disproving the Big Bang theory and cosmologists aren't panicking. Why, then, are we seeing viral social media posts and funky headlines that suggest the Big Bang didn't happen at all?To answer that question, and show why we should be skeptical of claims like this, we need to understand where the idea came from. Where did "The Big Bang Didn't Happen" come from?It all started with an article at The Institute of Art and Ideas (IAI), a British philosophical organization, on Aug. 11. The piece was written by Eric Lerner, who has long argued against the Big Big theory. He even wrote a book titled "The Big Bang Never Happened" in 1991. This provocatively-headlined article at IAI is also related to an upcoming debate Lerner is participating in, run by the IAI, dubbed "Cosmology and the Big Bust." Lerner's article gathered steam across social media, being shared widely on Twitter and across Facebook, over the last week. It makes sense why it's caught fire: It's a controversial idea that upends what we think we know about the cosmos. In addition, it's tied to a new piece of technology in James Webb, a telescope seeing parts of the universe we've never been able to see before. Including Webb as the news hook here suggests there's new data which overturns a long-standing theory.Don't get me wrong -- there is new and intriguing data emerging from the JWST. Just not the kind that would undo the Big Bang theory. Most of this new data trickles down to the public in the form of scientific pre-prints, articles that are yet to undergo peer review and land on repositories like arXiv, or popular press articles.Lerner's piece uses some of the early JWST studies to attempt to dismiss the Big Bang theory. What's concerning is how it misconstrues early JWST data to suggest astronomers and cosmologists are worried the well-established theory is incorrect. There are two points early in Lerner's article which show this:He points to a pre-print with the word "Panic!" in its title, calling it a "candid exclamation."He misuses a quote from Allison Kirkpatrick, an astronomer at the University of Kansas. The first point is just a case of Lerner missing the pun. The full title of the paper is "Panic! At the Disks: First Rest-frame Optical Observations of Galaxy Structure at z>3 with JWST in the SMACS 0723 Field." The first author of that pre-print, astronomer Leonardo Ferreira, is clearly riffing on popular 2000s emo band Panic! at the Disco with his title. It's a tongue-in-cheek reference, not a cosmological crisis. As for the second point, Lerner takes this quote from Allison Kirkpatrick, which comes from a Nature news article published on July 27:"Right now I find myself lying awake at three in the morning and wondering if everything I've done is wrong."This cherrypicked quote isn't in direct reference to the Big Bang theory. Rather, Kirkpatrick is reckoning with the first data coming back from the JWST about the early evolution of the universe. It's true there are some puzzles for astronomers to solve here but, so far, they aren't rewriting the beginning of the universe to do so. Kirkpatrick has stated her quotes were misused and even changed her Twitter name to "Allison the Big Bang happened Kirkpatrick." In addition, Lerner's article claims his ideas are being censored by the scientific establishment and later he also points to his theory being important to develop fusion energy on Earth. It's no coincidence the same paragraph links to LPPFusion, a company run by Lerner aimed at developing clean energy technologies.Why does this matter?One of the chief reasons the Big Bang theory stands up is because of the cosmic microwave background, or CMB. This was discovered in 1964. In short, the CMB is the radiation leftover from the Big Bang, right when the universe began and scientists have been able to "see" it with satellites that can detect that lingering radiation. So to bolster evidence the Big Bang theory is incorrect, you'd need to explain the CMB another way. Lerner's dismissive of the CMB and his proposal for the observation has been disproven in the past. If you're interested in further arguments against Lerner's hypotheses and why the claims don't add up, I recommend checking out Brian Keating's recent YouTube video. Keating is a cosmologist at the University of California, San Diego, and dives into a bit more detail about the limits of Lerner's arguments.It's also important to note Webb is not built to see and undertake new analyses of the CMB itself. The telescope can't "see" that far back in time. However, it will look at an epoch a few hundred million years after the Big Bang. What it finds there will almost certainly reshape our views on the early universe, galaxies and the evolution of the cosmos. But it's disingenuous to claim the early images and study results have contradicted the Big Bang theory.Science is about making incremental progress in our understanding, coming to increasingly stronger conclusions based on observations. The observations astrophysicists and cosmologists have made over decades line up with the Big Bang theory. They don't line up anywhere near as neatly if we use Lerner's alternative theory. That's doesn't mean scientists won't find evidence overturning the Big Bang theory. They just might! But, for now, it remains our best theory for explaining what we see. Scientific theories can -- and should -- be challenged by well-reasoned scientists presenting highly detailed and thoughtful arguments. This is not one of those times. And that means, despite the headlines, the Big Bang did happen.
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Cosmology & The Universe
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Our universe started with a bang that blasted everything into existence. But what happened next is a mystery. Scientists think that before atoms formed—or even the protons and neutrons they’re made of—there was probably a hot, soupy mix of two elementary particles called quarks and gluons, churning through space as a plasma. And because no one was around to observe the first moments of the cosmos, a coalition of researchers is trying to re-run history.Using the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, they have essentially created a “Little Bang” and are using it to probe the properties of that quark-gluon plasma. The findings will help cosmologists refine their still-fuzzy picture of the early universe, and how the oozy, blistering state of infant matter cooled and coalesced into the planets, stars, and galaxies of today. “We think about a microsecond after the Big Bang, the universe was in this stage,” says physicist Rongrong Ma, who works with the Solenoidal Tracker at the Relativistic Heavy Ion Collider, or STAR, a detector devoted to investigating the quark-gluon plasma. “So if we can understand from experiments the properties of such matter, this will feed into our understanding of how the universe evolved.” Scientists aren’t sure how long this plasma stage lasted—it could have been anywhere from a few seconds to thousands of years. It might even still exist today in the dense cores of neutron stars, or get made when super-high-energy particles crash into Earth’s atmosphere, so learning about its properties could help characterize the physics of the most extreme cosmic environments. These early days of the universe are impossible to study with telescopes, which can only reach as far back as the cosmic microwave background—the first light that emerged from the dense early universe, a hundred thousand years after the Big Bang. Everything before that is both literally and figuratively a dark era of cosmology. Theoretical simulations can help fill in that gap, says Jaki Noronha-Hostler, a nuclear physicist at the University of Illinois Urbana-Champaign, but detectors like STAR “allow you to experimentally understand a system that’s very similar to the Big Bang.” In addition, quarks and gluons are never found solo in nature, making it difficult to study them in isolation. “We can’t just pluck one out and examine it,” says Helen Caines, a physicist at Yale University and spokesperson for the STAR experiment. Instead, they’re stuck in composite states: protons, neutrons, and more exotic matter like upsilons, pions, and kaons. But at high enough temperatures, the boundaries between these composite particles begin to blur. “And that is the quark-gluon plasma,” Caines says. They’re still confined to some volume, but the quarks and gluons within this space are no longer fused together. In fact, she says, “plasma” might be a bit of a misnomer, because it actually behaves more like a fluid, in that it flows.In March, scientists at Brookhaven reported in Physical Review Letters that they were able to generate the quark-gluon plasma for a brief blip in time by accelerating two beams of gold nuclei close to the speed of light, then smashing them into each other. Then came the clever bit: They used this collision to calculate how hot the post-Big Bang plasma would have been.To do this, they needed to look for upsilons, which weren’t actually present at the beginning of the universe but are a byproduct of the Brookhaven beam collisions. Upsilons are comprised of a quark and its antimatter twin bound together in one of three configurations: a tightly tethered “ground state” and two excited states, one looser than the other. Slamming the gold nuclei together produces a slew of them in each of these three states.“The idea is to use these particles as a thermometer,” Caines says. A plasma like the one that theoretically existed microseconds after the Big Bang can rip these upsilons apart; interactions with the free quarks and gluons melt them down to their most basic elements. And each state has its own “melting point.” Ground-state upsilons would need the most energy—the hottest temperatures—to fall apart, and the more loosely bound quark-antiquark pairs would need less. So recreating post-Bang plasma conditions, then counting how many upsilons of each state survived, would reveal what the temperature was in those first moments of the universe. That, in turn, would tell physicists about other properties of the quark-gluon plasma, because its temperature is intrinsically linked to its density, pressure, and viscosity. Ultimately, scientists want to be able to solve what they call an equation of state: a mathematical expression describing all of the plasma’s properties, how they influence each other, and how they evolve with time. The quark-gluon plasma is a unique system: It’s extremely hot but also tiny—on the order of the diameter of a proton, Noronha-Hostler says. So it doesn’t obey the usual laws of how fluids act. “We can write down equations, but we can’t solve them,” she says. Once this behavior is understood, cosmologists can extrapolate how long the universe must have been in this soupy state, and what physical processes drove a transition into the more familiar protons, neutrons, and other particles that matter is made up of today. This was actually the second time scientists had done such a test; the first was in 2012 using the Large Hadron Collider at CERN, which accelerates particles to energies a factor of 25 higher than what can be achieved at Brookhaven. Studying the plasma at lower energies helps scientists understand the temperature dependence of its properties, giving them another data point that can be used to tune theoretical models of the early cosmos. “In the field that we’re in, you really want to do things at a range of energies,” says Brookhaven physicist David Morrison, who was not involved in the work. Hotter plasma is a better probe for earlier in the universe, but the lower temperature state made at Brookhaven is closer to what the system may have looked like when the quarks and gluons began to merge. This time, after smashing gold nuclei in the STAR detector, the researchers counted how many upsilons they saw in each state and compared that to a model of how many should have been created by the collision—before the plasma melted them. They found that about 60 percent of the upsilons in the ground state, and 70 percent of those in the intermediate state, were missing, presumed melted. Upsilons with the most loosely bound quark and antiquark pair seemed to be completely gone. Combining past melting measurements with their newly collected data, the STAR team determined a lower limit on the temperature needed to make the plasma: at least a trillion degrees. (That’s almost a million times more sizzling than the center of the sun.) Their atom smashing had managed to achieve this temperature for an incredibly brief 10-23 of a second.The STAR team is gearing up to redo their upsilon measurement at Brookhaven with about 20 times more data, which will help nail down whether the particles with the most loosely bound quark-antiquark pair truly vanished or just survived at rates too low to be detected. A different detector, called sPHENIX, will also turn on at the lab within the next month. The thousand-ton instrument, built around an ultracold, superconducting magnetic core, will be able to investigate this melting effect with even higher precision. “This STAR paper had hundreds of upsilons,” says Morrison, who is a spokesperson for the sPHENIX collaboration. “We’ll be measuring tens of thousands.”Ultimately, upsilons are only one part of the puzzle when trying to understand the properties of the quark-gluon plasma, Ma says. Physicists can also look for individual quark collisions, study photons emanating from the plasma, or try to figure out the types and production rates of other particles resulting from the gold nuclei blasts. These different types of measurements will help physicists connect phenomena they understand into explanations for what they don’t. “We try to put all these together, using a multi-messenger approach to build a full picture of the quark-gluon plasma,” Ma says—“for a theory that can explain everything.”
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Cosmology & The Universe
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The European Space Agency's (ESA) dark universe detective, the Euclid spacecraft, is on track after locating its guiding stars, which it lost as a result of cosmic misidentification.
The satellite can now begin investigating dark matter and dark energy, which are some of the greatest mysteries in cosmology. Dark matter accounts for 85% of the matter in the universe but is effectively invisible, and dark energy causes the cosmos to expand at an ever-increasing rate.
Euclid launched to investigate these cosmological mysteries, sometimes collectively known as the dark universe, on July 1 and took a four-week journey to Lagrange point 2, a gravitationally stable point in the Earth-sun system. Although Euclid reached its destination safely, its operators noticed a problem after the spacecraft took its first incredible images of the cosmos: Euclid's Fine Guidance Sensor was having trouble finding its guiding stars, which Euclid uses for navigation and thus are crucial to enabling it to point at precise areas of the sky.
The cause of this issue was cosmic rays — charged particles that the sun emits during periods of high solar activity. The cosmic rays were impacting the Fine Guidance Sensor, creating signals that Euclid was incorrectly identifying as stars. In addition, stray light from the sun and solar X-rays were interfering with the spacecraft. As a result, artifacts caused by this interference occasionally outnumbered the real stars being spotted by Euclid, meaning the spacecraft couldn't resolve the star patterns it needed to navigate.
A striking example of the effect of this hiccup on Euclid's operations is an image of a distant star field that shows strange loops and lassos, which, although beautiful, aren't helpful in the search for the subtle patterns in distant galaxies and star clusters that could reveal clues about dark energy and dark matter.
Ironing out Euclid's teething troubles
These types of glitches are often experienced during the initial phase of a spacecraft's operations, known as the commissioning phase. Teams at ESA mission control have been working around the clock to better equip the craft for its space-based environment.
The mission team created a software patch that was first applied to an electric model of Euclid here on Earth before being tested on the real thing at Lagrange point 2, which is around 1 million miles (1.5 million kilometers) from home, ESA officials said in a statement. After being updated and undergoing 10 days of testing in orbit, the Fine Guidance Sensor is working as intended, and Euclid's guide stars have once again been located.
"Our industrial partners — Thales Alenia Space and Leonardo — went back to the drawing board and revised the way the Fine Guidance Sensor identifies stars," Micha Schmidt, Euclid spacecraft operations manager, said in the statement. "After a major effort and in record time, we were provided with new on-board software to be installed on the spacecraft. We carefully tested the software update step by step under real flight conditions, with realistic input from the Science Operations Centre for observation targets."
Euclid is now ready to restart its all-important performance verification phase, which was interrupted in August , during which final testing will be performed.
"The performance verification phase that was interrupted in August has now fully restarted, and all the observations are carried out correctly," Giuseppe Racca, Euclid project manager, said in the statement. "This phase will last until late November, but we are confident that the mission performance will prove to be outstanding and the regular scientific survey observations can start thereafter."
This is the last step before Euclid can start investigating the dark universe. Euclid will do this by examining around a third of the sky over Earth and by looking back over 10 billion years of cosmic history, mapping 3D models of galaxies to see how the 13.8 billion-year-old universe has taken shape and what role dark matter has played in this evolution. Euclid will also look at large-scale galactic disturbance to see the influence of dark energy as it pushes galaxies apart faster and faster.
"Now comes the exciting phase of testing Euclid in science-like conditions, and we are looking forward to its first images showcasing how this mission will revolutionize our understanding of the dark universe," Carole Mundell, ESA's director of science, said in the statement.
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Cosmology & The Universe
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The wait, it seems, was worth it. Decades after researchers first proposed what became known as the James Webb space telescope, the first colour images have landed and with them a tantalising glimpse of the observatory’s power to peer back in time to the moment when the first stars lit up the universe.Major accomplishments in space observation always ride on a wave of PR and on Monday it was President Joe Biden who unveiled the first colour image, noting the deep implications for Homo sapiens. It was “an historic moment” he said, not only for science and technology, but “for America and all of humanity”.The paradox of fanfare is that it obscures the achievement. In the case of Webb, as the $10bn Nasa observatory is known, the accomplishment is concrete and substantial. Nasa’s Hubble defined our view of the heavens for the past 30 years, and now Webb, its successor, is poised to shape our understanding for many decades to come.‘Blows my mind’: first full-colour image of ancient galaxies – videoThe image Nasa released on Monday showcases the observatory’s ability to look far back towards the dawn of time. In the foreground is the rich cluster of galaxies known as SMACS 0723, which lies nearly 5bn light years from Earth. But it is the other galaxies in the image that have astronomers most excited. Because of the intense gravitational forces the cluster produces, it behaves like an astronomical lens, magnifying light from galaxies behind it and revealing them in unprecedented clarity. It is this depth and quality of the images that researchers find breathtaking: the fresh details Webb reveals will be pored over by scientists worldwide.In the first image, the SMACS 0723 galaxy cluster appears as it was 4.6bn years ago, the time it took light from the cluster to race across space to Webb’s mirror. More distant galaxies in the image are about 13bn years old. But future images are expected to capture even more ancient galaxies, pushing back 13.5bn years, to the earliest period of the universe. The ultimate prize for many astronomers is to pinpoint “cosmic dawn” – the moment when the universe was first bathed in starlight.Webb’s impressive performance comes from its remote position in space, a spot 1m miles from Earth called the second Lagrange point, or L2, its large mirror, and the extreme sensitivity of its infrared instruments. Together these allow the observatory to see much fainter, older galaxies than Hubble ever could as well as other cosmic objects. The images and accompanying data will feed directly into astronomers’ understanding of how the first stars and galaxies formed.Webb will do more than look back to the early stirrings of the universe. On Tuesday, Nasa will release more images to give a flavour of what the telescope can do. Beyond the SMACS 0723 cluster, the telescope has peered at the Carina Nebula, a vast stellar nursery 7,600 light years away that is home to stars far larger than the sun. Another target is the Southern Ring Nebula, an enormous and expanding cloud of gas that surrounds a dying star. Yet another is Stephan’s Quintet, a cluster of galaxies that is so compact, two of them are merging into one.It is not all about glorious images, though. A major theme of Webb’s science involves spectroscopy, which analyses the wavelengths of light captured by the telescope. This can reveal fresh details about cosmic objects that are not evident in visible light. Data released on Tuesday are expected to show the spectra from a planet called Wasp 96b, a cloudless planet half the size of Jupiter 1,150 light years from Earth. The same technique will be used to study the chemical compositions of atmospheres around distant worlds, and potentially highlight faraway planets where conditions appear ripe for life.Based on the images received so far, astronomers believe they can do all the science they had hoped for with Webb, and plenty more besides. Against the odds, the observatory made it to the launch pad, reached its destination unscathed, and appears to be operating beautifully. For researchers, the waves of relief are now waves of excitement: now the real work begins.
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Cosmology & The Universe
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Media releaseFrom: Macquarie University
In a paper published today in Science, a global team led by Macquarie University’s Dr Stuart Ryder and Swinburne University of Technology’s Associate Professor Ryan Shannon, report on their discovery of the most ancient and distant fast radio burst located to date, about eight billion years old.
The discovery smashes the team’s previous record by 50 per cent. It confirms that fast radio bursts (FRBs) can be used to measure the “missing” matter between galaxies.
The source of the burst was shown to be a group of two or three galaxies that are merging, supporting current theories on the cause of fast radio bursts. The team also showed that eight billion years is about as far back as we can expect to see and pinpoint fast radio bursts with current telescopes.
On 10 June 2022, CSIRO’s ASKAP radio telescope on Wajarri Yamaji Country was used to detect a fast radio burst, created in a cosmic event that released, in milliseconds, the equivalent of our Sun’s total emission over 30 years.
“Using ASKAP’s array of dishes, we were able to determine precisely where the burst came from,” says Dr Ryder, the first author on the paper. “Then we used the European Southern Observatory (ESO) Very Large Telescope (VLT) in Chile to search for the source galaxy, finding it to be older and further away than any other FRB source found to date, and likely within a small group of merging galaxies.”
Named FRB 20220610A, the fast radio burst has reaffirmed the concept of weighing the Universe using data from FRBs. This was first demonstrated by the late Australian astronomer Jean-Pierre ‘J-P’ Macquart in a paper in Nature in 2020.
“J-P showed that the further away a fast radio burst is, the more diffuse gas it reveals between the galaxies,” says Dr Ryder. “This is now known as the Macquart relation. Some recent fast radio bursts appeared to break this relationship. Our measurements confirm the Macquart relation holds out to beyond half the known Universe.”
About 50 FRBs have been pinpointed to date – nearly half using ASKAP. The authors suggest we should be able to detect thousands of them across the sky, and at even greater distances.
“While we still don’t know what causes these massive bursts of energy, the paper confirms that fast radio bursts are common events in the cosmos and that we will be able to use them to detect matter between galaxies, and better understand the structure of the Universe,” says Associate Professor Shannon.
And we will soon have the tools to do so. ASKAP is currently the best radio telescope to detect and locate FRBs. The international SKA telescopes now under construction in Western Australia and South Africa will be even better at allowing astronomers to locate even older and more distant FRBs. The nearly 40-metre mirror of ESO’s Extremely Large Telescope, currently under construction in the high, dry Chilean desert will then be needed to study their source galaxies.
The project was a world-wide effort with researchers from ASTRON (Netherlands), Pontificia Universidad Católica de Valparaíso (Chile), Kavli Institute for the Physics and Mathematics of the Universe (Japan), SKA Observatory (UK), Northwestern University, UC Berkeley, and UC Santa Cruz (USA).
Australian participants were Macquarie University, Swinburne University of Technology, CSIRO, ICRAR/Curtin University, ASTRO 3D, and University of Sydney.
Current methods of estimating the mass of the Universe are giving conflicting answers and challenging the standard model of cosmology.
“If we count up the amount of normal matter in the Universe – the atoms that we are all made of – we find that more than half of what should be there today is missing,” says Associate Professor Shannon.
“We think that the missing matter is hiding in the space between galaxies, but it may just be so hot and diffuse that it's impossible to see using normal techniques.
“Fast radio bursts sense this ionised material. Even in space that is nearly perfectly empty they can ‘see’ all the electrons, and that allows us to measure how much stuff is between the galaxies.”
CSIRO's ASKAP radio telescope is situated at Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory in Western Australia, about 800 kilometres north of Perth.
Currently, 16 countries are partners in the SKA Observatory, which is building two radio telescopes. SKA-Low (the low frequency telescope) – at the same site as ASKAP – will comprise 131,072 two-metre-tall antennas, while SKA-Mid (the mid frequency telescope) in South Africa will comprise 197 dishes.
The Very Large Telescope (VLT) has four eight-metre mirrors and is operated by the European Southern Observatory, located on Cerro Paranal in the Atacama Desert of northern Chile. Australia is a strategic partner of ESO, giving Australian astronomers access to the VLT and the opportunity to contribute new technologies to it.
Australian astronomers are also hoping to gain access to ESO’s Extremely Large Telescope when it starts operation later this decade. The ELT will be able to deliver images 15 times sharper than the Hubble Space Telescope.
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Cosmology & The Universe
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Nature Timespiral: The Evolution of Earth from the Big Bang
Since the dawn of humanity, we have looked questioningly to the heavens with great interest and awe. We’ve called on the stars to guide us, and have made some of humanity’s most interesting discoveries based on those observations. This also led us to question our existence and how we came to be in this moment in time.
That journey began some 14 billion years ago, when the Big Bang led to the universe emerging from a hot, dense sea of matter and energy. As the cosmos expanded and cooled, they spawned galaxies, stars, planets, and eventually, life.
In the above visualization, Pablo Carlos Buddassi illustrates this journey of epic proportions in the intricately designed Nature Timespiral, depicting the various eras that the Earth has gone through since the inception of the universe itself.
Evolutionary Timeline of the World
Not much is known about what came before the Big Bang, but we do know that it launched a sequence of events that gave rise to the universal laws of physics and the chemical elements that make up matter. How the Earth came about, and life subsequently followed, is a wondrous story of time and change.
Let’s look at what transpired after the Big Bang to trace our journey through the cosmos.
The Big Bang and Hadean Eon
The Big Bang formed the entire universe that we know, including the elements, forces, stars, and planets. Hydrogen and massive dissipation of heat dominated the initial stages of the universe.
During a time span known as the Hadean eon, our Solar System formed within a large cloud of gas and dust. The Sun’s gravitational pull brought together spatial particles to create the Earth and other planets, but they would take a long time to reach their modern forms. Archean Eon (4 – 2.5 billion years ago)
After its initial formation, the surface of the Earth was extremely hot and entirely liquid. This subsequent eon saw the planet cool down massively, solidifying some of the liquid surface and giving rise to oceans and continents, as well as the first recorded history of rocks.
Early in this time frame, known as the Archean eon, life appeared on Earth. The oldest discovered fossils, consisting of tiny, preserved microorganisms, date to this eon roughly 3.5 billion years ago.
Paleoproterozoic Era (2.5 – 1.6 billion years ago)
The first era of the Proterozoic Eon, the Paleoproterozoic, was the longest in Earth’s geological history. Tectonic plates arose and landmasses shifted across the globe—it was the beginning of the formation of the Earth we know today.
Cyanobacteria, the first organisms using photosynthesis, also appeared during this period. Their photosynthetic activity brought about a rapid upsurge in atmospheric oxygen, resulting in the Great Oxidation Event. This killed off many primordial anaerobic bacterial groups but paved the way for multicellular life to grow and flourish.
Mesoproterozoic Era (1.6 – 1 billion years ago)
The Mesoproterozoic occurred during what is known as the “boring billion” stage of Earth’s history. That is due to a lack of widespread geochemical activity and the relative stability of the ocean carbon reservoirs.
But this era did see the break-up of the supercontinents and the formation of new continents. This period also saw the first noted case of sexual reproduction among organisms and the probable appearance of multicellular organisms and green plants.
Neoproterozoic Era (1 billion – 542.0 million years ago)
In some respects, the Neoproterozoic era is one of the most profound time periods in Earth’s history. It bookends two major moments in the planet’s evolutionary timeline, with predominantly microbial life on one side, and the introduction of diverse, multicellular organisms on the other.
At the same time, Earth also experienced severe glaciations known as the Cryogenian Period and its first ice age, also known as Snowball Earth.
The era saw the formation of the ozone layer and the earliest evidence of multicellular life, including the emergence of the first hard-shelled animals, such as trilobites and archaeocyathids.
Paleozoic Era (541 million – 252 million years ago)
The Paleozoic is best known for ushering in an explosion of life on Earth, with two of the most critical events in the history of animal life. At its beginning, multicellular animals underwent a dramatic Cambrian explosion in aquatic diversity, and almost all living animals appeared within a few millions of years.
At the other end of the Paleozoic, the largest mass extinction in history resulted in 96% of marine life and 70% of terrestrial life dying out. Halfway between these events, animals, fungi, and plants colonized the land, and the insects took to the air.
Mesozoic Era (252 million – 66 million years ago)
The Mesozoic was the Age of Reptiles. Dinosaurs, crocodiles, and pterosaurs ruled the land and air. This era can be subdivided into three periods of time: Triassic (252 to 201.3 million years ago)
Jurassic (201.3 to 145 million years ago)
Cretaceous (145 to 66 million years ago) The rise of the dinosaurs began at the end of the Triassic Period. A fossil of one of the earliest-known dinosaurs, a two-legged omnivore roughly three feet long-named Eoraptor, is dated all the way back to this time.
Scientists believe the Eoraptor (and a few other early dinosaurs still being discovered today) evolved into the many species of well-known dinosaurs that would dominate the planet during the Jurassic period. They would continue to flourish well into the Cretaceous period, when it is widely accepted that the Chicxulub impactor, the plummeting asteroid that crashed into Earth off the coast of Mexico, brought about the end of the Age of Reptiles.
Cenozoic Era (66 million – Present Day)
After the end of the Age of Dinosaurs, this era saw massive adaptations by natural flora and fauna to survive. The plants and animals that formed during this era look most like those on Earth today.
The earliest forms of modern mammals, amphibians, birds, and reptiles can be traced back to the Cenozoic. Human history is entirely contained within this period, as apes developed through evolutionary pressure and gave rise to the present-day human being or Homo sapiens.
Compared to the evolutionary timeline of the world, human history has risen quite rapidly and dramatically. Going from our first stone tools and the Age of the Kings to concrete jungles with modern technology may seem like a long journey, but compared to everything that came before it, is but a brief blink of an eye.
*Editor’s note: An earlier version of this article contained errors in the header graphic and an incorrect citation, and has since been updated.
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Cosmology & The Universe
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The measurements from ancient and dormant galaxies show black holes growing more than expected, aligning with a phenomenon predicted in Einstein's theory of gravity. The result potentially means nothing new has to be added to our picture of the Universe to account for dark energy: black holes combined with Einstein's gravity are the source.
The conclusion was reached by a team of 17 researchers in nine countries, led by the University of Hawai'i and including STFC RAL Space and Imperial College London physicists. The work is published in two papers in the journals The Astrophysical Journal and The Astrophysical Journal Letters.
Study co-author Dr Chris Pearson, from STFC RAL Space, said: “If the theory holds, then this is going to revolutionise the whole of cosmology, because at last we've got a solution for the origin of dark energy that's been perplexing cosmologists and theoretical physicists for more than 20 years."
Study co-author Dr Dave Clements, from the Department of Physics at Imperial, said: “This is a really surprising result. We started off looking at how black holes grow over time, and may have found the answer to one of the biggest problems in cosmology."
NGC 524 is a galaxy in the constellation Pisces, and is one of the galaxies observed in this study. It is at a distance of about 90 million light years away from Earth. Credit: ESA/Hubble
Gravity versus dark energy
In the 1990s, it was discovered that the expansion of the Universe is accelerating – everything is moving away from everything else at a faster and faster rate. This is difficult to explain – the pull of gravity between all objects in the Universe should be slowing the expansion down.
To account for this, it was proposed that a 'dark energy' was responsible for pushing things apart more strongly than gravity. This was linked to a concept Einstein had proposed but later discarded – a 'cosmological constant' that opposed gravity and kept the Universe from collapsing.
This concept was revived with the discovery of the accelerating expansion of the Universe, with its main component being a kind of energy included in spacetime itself, called vacuum energy. This energy pushes the Universe further apart, accelerating the expansion.
Black holes posed a problem though – their extremely strong gravity is hard to oppose, especially at their centres, where everything seems to break down in a phenomenon called a 'singularity'.
The new result shows that black holes gain mass in a way consistent with them containing vacuum energy, providing a source of dark energy and removing the need for singularities to form at their centre.
Another galaxy observed in this study, NGC 1316 (also known as Fornax A) is a about 60 million light-years away in the constellation Fornax. Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)
Black hole growing pains
The conclusion was made by studying nine billion years of black hole evolution. Black holes are formed when massive stars come to the end of their life. When found at the centres of galaxies, they are called supermassive black holes. These contain millions to billions of times the mass of our Sun inside them in a comparatively small space, creating extremely strong gravity.
Black holes can increase in size by accreting matter, such as by swallowing stars that get too close, or by merging with other black holes. To discover whether these effects alone could account for the growth of supermassive black holes, the team looked at data spanning nine billion years.
The researchers looked at a particular type of galaxy called giant elliptical galaxies, which evolved early in the Universe and then became dormant. Dormant galaxies have finished forming stars, leaving little material for the black hole at their centre to accrete, meaning any further growth cannot be explained by these normal astrophysical processes.
Comparing observations of distant galaxies (when they were young) with local elliptical galaxies (which are old and dead) showed growth much larger than predicted by accretion or mergers: the black holes of today are 7—20 times larger than they were nine billion years ago.
Cosmological coupling
Further measurements with related populations of galaxies at different points in the Universe's evolution show good agreement between the size of the Universe and the mass of the black holes. These show that the measured amount of dark energy in the Universe can be accounted for by black hole vacuum energy.
This is the first observational evidence that black holes actually contain vacuum energy and that they are 'coupled' to the expansion of the Universe, increasing in mass as the Universe expands – a phenomenon called 'cosmological coupling'. If further observations confirm it, cosmological coupling will redefine our understanding of what a black hole is.
Study first author Duncan Farrah, University of Hawai`i Astronomer and former Imperial PhD student, said: “We're really saying two things at once: that there's evidence the typical black hole solutions don't work for you on a long, long timescale, and we have the first proposed astrophysical source for dark energy.
“What that means, though, is not that other people haven't proposed sources for dark energy, but this is the first observational paper where we're not adding anything new to the Universe as a source for dark energy: black holes in Einstein's theory of gravity are the dark energy.''
Additional information
Study co-author Dr Chris Pearson, Astronomy Group Leader at RAL Space, explains this story in a short video:
Link to published paper: https://iopscience.iop.org/article/10.3847/2041-8213/acb704
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Cosmology & The Universe
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In 1998 Stephen Hawking took me on as his PhD student “to work on a quantum theory of the Big Bang”. What started out as a doctoral project evolved over some 20 years into an intense collaboration that ended only with his passing five years ago on March 14, 2018.
The enigma at the centre of our research throughout this period was how the Big Bang could have created conditions so perfectly hospitable to life. What are we to make of this mysterious appearance of intent?
Such questions take physics far out of its comfort zone. Yet this was exactly where Hawking liked to venture. After all, the prospect – or hope – of being able to crack the riddle of cosmic design drove much of his work.
Our shared scientific quest meant that inevitably we grew close. Being around him, one could not fail to be influenced by his determination and by his epistemic optimism that we could tackle these mystifying cosmic questions.
He made us feel as if we were writing our own creation story, which, in a sense, we did.
The idea that time had a beginning in a Big Bang was championed in the early 1930s by the Belgian priest-astronomer Georges Lemaître. Albert Einstein famously rejected it, because it reminded him of Christian dogma. But eventually Hawking and Roger Penrose proved Lemaître right.
Ever since, the origin of time has been the cornerstone, but also the Achilles’ heel of Big Bang cosmology. For how exactly could time pop into existence?
Hawking’s final theory of the Big Bang provides a bold and surprising answer. It envisages the Universe as a holographic projection.
In a familiar hologram, a third dimension of space emerges from the lines and scribbles on a screen. In the cosmos-as-hologram idea, which has become the talk of the town among theoretical physicists, it is the dimension of time that can be holographically encoded.
Read more:
- Where did the Big Bang take place?
- If energy can't be created, where did it come from in the first place?
Stephen liked to visualise this idea in a disk-like image of the kind shown above. The outer circle depicts a timeless hologram consisting of countless entangled qubits.
The disk shows the evolution of an expanding Universe that projects down from this. The origin of the Universe lies at the centre of the disk and it expands outward in the radial direction.
It is as if there is a code operating on the entangled qubits that brings about the Universe and this is what we perceive as the flow of time.
Crucially, by taking a fuzzier view of the hologram, one ventures farther back in time, toward the interior of the disk. It is like zooming out. Eventually, however, one runs out of bits. This is the origin of time, according to our theory.
There can be nothing before the Big Bang, because the past that holographically emerges doesn’t extend further back.
These insights yield a new twist on the riddle of cosmic design. The early Hawking sought to describe the origin of the Universe as a quantum creation event.
In those days, Stephen strove to give a fundamentally causal explanation of the origin of the Universe: why, not how. But the discovery of holography advances a radically different view of cosmogenesis.
It says that physics itself fades away when we journey back into the Big Bang. The Big Bang emerges from holography not so much as the beginning of time but more as the beginning of laws.
What is left, then, of the age-old question of the ultimate cause of the Big Bang? It would seem to evaporate, the late Hawking held. Not the laws as such but their capacity to change and transmute has the final word.
Dr Thomas Hertog is a Belgian cosmologist at KU Leuven University and author of On The Origin Of Time: Stephen Hawking's Final Theory, is published 4 April 2023 (£20, Penguin). It is available for pre-order at Penguin and Amazon UK Read more:
Dr Thomas Hertog is a Belgian cosmologist at KU Leuven University and author of On The Origin Of Time: Stephen Hawking's Final Theory, is published 4 April 2023 (£20, Penguin). It is available for pre-order at Penguin and Amazon UK
Read more:
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Cosmology & The Universe
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AbstractFast radio bursts (FRBs) are highly dispersed, millisecond-duration radio bursts1,2,3. Recent observations of a Galactic FRB4,5,6,7,8 suggest that at least some FRBs originate from magnetars, but the origin of cosmological FRBs is still not settled. Here we report the detection of 1,863 bursts in 82 h over 54 days from the repeating source FRB 20201124A (ref. 9). These observations show irregular short-time variation of the Faraday rotation measure (RM), which scrutinizes the density-weighted line-of-sight magnetic field strength, of individual bursts during the first 36 days, followed by a constant RM. We detected circular polarization in more than half of the burst sample, including one burst reaching a high fractional circular polarization of 75%. Oscillations in fractional linear and circular polarizations, as well as polarization angle as a function of wavelength, were detected. All of these features provide evidence for a complicated, dynamically evolving, magnetized immediate environment within about an astronomical unit (au; Earth–Sun distance) of the source. Our optical observations of its Milky-Way-sized, metal-rich host galaxy10,11,12 show a barred spiral, with the FRB source residing in a low-stellar-density interarm region at an intermediate galactocentric distance. This environment is inconsistent with a young magnetar engine formed during an extreme explosion of a massive star that resulted in a long gamma-ray burst or superluminous supernova. This is a preview of subscription content, access via your institution Access options Subscribe to Nature+Get immediate online access to the entire Nature family of 50+ journalsSubscribe to JournalGet full journal access for 1 year$199.00only $3.90 per issueAll prices are NET prices. VAT will be added later in the checkout.Tax calculation will be finalised during checkout.Buy articleGet time limited or full article access on ReadCube.$32.00All prices are NET prices. Additional access options: Log in Learn about institutional subscriptions Data availability Raw data are available from the FAST Data Center, http://fast.bao.ac.cn. Owing to the large data volume, we encourage contacting the corresponding author for the data transfer. The directly related data that support the findings of this study can be found at the PSRPKU website, https://psr.pku.edu.cn/index.php/publications/frb20201124a/ and the Figshare website, https://doi.org/10.6084/m9.figshare.19688854. ReferencesPetroff, E., Hessels, J. W. T. & Lorimer, D. R. Fast radio bursts. Astron. Astrophys. Rev. 27, 4 (2019).ADS Article Google Scholar Cordes, J. M. & Chatterjee, S. Fast radio bursts: an extragalactic enigma. Annu Rev. Astron. Astrophys. 57, 417–465 (2019).ADS Article Google Scholar Zhang, B. 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This work made use of data from the FAST. The FAST is a Chinese national megascience facility, built and operated by the National Astronomical Observatories, Chinese Academy of Sciences. We acknowledge the use of public data from the Fermi Science Support Center (FSSC). This work is supported by the National SKA Program of China (2020SKA0120100, 2020SKA0120200), the Natural Science Foundation of China (12041304, 11873067, 11988101, 12041303, 11725313, 11725314, 11833003, 12003028, 12041306, 12103089, U2031209, U2038105, U1831207), the National Program on Key Research and Development Project (2019YFA0405100, 2017YFA0402602, 2018YFA0404204, 2016YFA0400801), the Key Research Program of the CAS (QYZDJ-SSW-SLH021), the Natural Science Foundation of Jiangsu Province (BK20211000), the Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CAS, the Strategic Priority Research Program on Space Science, the Chinese Academy of Sciences (grants XDA15360000, XDA15052700, XDB23040400), funding from the Max Planck Partner Group, the science research grants from the China Manned Space Project (CMS-CSST-2021-B11, CMS-CSST-2021-A11) and PKU development grant 7101502590. A.V.F.’s group at University of California, Berkeley is supported by the Christopher R. Redlich Fund, the Miller Institute for Basic Research in Science (in which A.V.F. was a Miller Senior Fellow) and many individual donors. S.D. acknowledges support from the Xplorer Prize. B.B.Z. is supported by Fundamental Research Funds for the Central Universities (14380046) and the Program for Innovative Talents, Entrepreneur in Jiangsu. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and NASA; the observatory was made possible by the financial support of the W. M. Keck Foundation. We thank the Keck staff for their help during the observing runs.Author informationAuthors and AffiliationsKavli Institute for Astronomy and Astrophysics, Peking University, Beijing, P. R. ChinaH. Xu, P. Chen, K. J. Lee, S. Dong, J. C. Jiang, B. J. Wang, J. W. Xu, C. F. Zhang, E. W. Peng, R. N. Caballero & R. X. XuNational Astronomical Observatories, Chinese Academy of Sciences, Beijing, P. R. ChinaH. Xu, J. R. Niu, K. J. Lee, W. W. Zhu, J. C. Jiang, B. J. Wang, J. W. Xu, C. F. Zhang, D. J. Zhou, Y. K. Zhang, P. Wang, Y. Feng, H. Q. Gan, J. L. Han, P. Jiang, D. Li, H. Li, C. H. Niu, L. Qian, J. H. Sun, R. Yao, Y. L. Yue, D. J. Yu & Y. ZhuDepartment of Astronomy, Peking University, Beijing, P. R. ChinaH. Xu, P. Chen, J. C. Jiang, B. J. Wang, J. W. Xu, C. F. Zhang, E. W. Peng, W. Y. Wang & R. X. XuUniversity of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, P. R. ChinaJ. R. Niu, D. J. Zhou & Y. K. ZhangDepartment of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot, IsraelP. ChenNevada Center for Astrophysics, University of Nevada, Las Vegas, Las Vegas, NV, USAB. ZhangDepartment of Physics and Astronomy, University of Nevada, Las Vegas, Las Vegas, NV, USAB. ZhangDepartment of Physics and Astronomy, University of Iowa, Iowa City, IA, USAH. FuDepartment of Astronomy, University of California, Berkeley, Berkeley, CA, USAA. V. Filippenko, T. G. Brink & W. K. ZhengZhejiang Lab, Hangzhou, P. R. ChinaY. FengPurple Mountain Observatory, Chinese Academy of Sciences, Nanjing, P. R. ChinaY. Li, X. F. Wu, X. Yang & S. B. ZhangTAPIR, Walter Burke Institute for Theoretical Physics, California Institute of Technology, Pasadena, CA, USAD. Z. LiDepartment of Astrophysical Sciences, Princeton University, Princeton, NJ, USAW. LuSouth-Western Institute For Astronomy Research, Yunnan University, Kunming, P. R. ChinaY. P. YangKey Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, P. R. ChinaC. Cai, C. K. Li, X. Q. Li, W. X. Peng, L. M. Song, S. Xiao, S. L. Xiong, Q. B. Yi, S. N. Zhang & Y. ZhaoXinjiang Astronomical Observatory, Chinese Academy of Sciences, Ürümqi, P. R. ChinaM. Z. Chen, A. Esamdin, Z. Y. Liu, N. Wang & J. P. YuanUniversity of Science and Technology of China, Hefei, P. R. ChinaZ. G. DaiDivision of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA, USAS. G. DjorgovskiUCO/Lick Observatory, Department of Astronomy & Astrophysics, University of California, Santa Cruz, Santa Cruz, CA, USAP. GuhathakurtaYunnan Observatories, Chinese Academy of Sciences, Kunming, P. R. ChinaL. F. Hao, Y. X. Huang, Z. X. Li, M. Wang & Y. H. XuGuizhou Normal University, Guiyang, P. R. ChinaD. LiCSIRO Space and Astronomy, Epping, New South Wales, AustraliaR. LuoMax-Planck-Institut für Radioastronomie, Bonn, GermanyY. P. MenJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USAD. SternInstitute for Astronomy, University of Hawaii, Honolulu, HI, USAA. StocktonSchool of Astronomy and Space Science, Nanjing University, Nanjing, P. R. ChinaF. Y. Wang, J. Yang, B. B. Zhang & J. H. ZouState Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing, P. R. ChinaR. X. XuShanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai, P. R. ChinaW. F. YuKey Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing, P. R. ChinaB. B. ZhangCollege of Physics, Hebei Normal University, Shijiazhuang, P. R. ChinaJ. H. ZouAuthorsH. XuYou can also search for this author in PubMed Google ScholarJ. R. NiuYou can also search for this author in PubMed Google ScholarP. ChenYou can also search for this author in PubMed Google ScholarK. J. LeeYou can also search for this author in PubMed Google ScholarW. W. ZhuYou can also search for this author in PubMed Google ScholarS. DongYou can also search for this author in PubMed Google ScholarB. ZhangYou can also search for this author in PubMed Google ScholarJ. C. JiangYou can also search for this author in PubMed Google ScholarB. J. WangYou can also search for this author in PubMed Google ScholarJ. W. XuYou can also search for this author in PubMed Google ScholarC. F. ZhangYou can also search for this author in PubMed Google ScholarH. FuYou can also search for this author in PubMed Google ScholarA. V. FilippenkoYou can also search for this author in PubMed Google ScholarE. W. PengYou can also search for this author in PubMed Google ScholarD. J. ZhouYou can also search for this author in PubMed Google ScholarY. K. ZhangYou can also search for this author in PubMed Google ScholarP. WangYou can also search for this author in PubMed Google ScholarY. FengYou can also search for this author in PubMed Google ScholarY. LiYou can also search for this author in PubMed Google ScholarT. G. BrinkYou can also search for this author in PubMed Google ScholarD. Z. LiYou can also search for this author in PubMed Google ScholarW. LuYou can also search for this author in PubMed Google ScholarY. P. YangYou can also search for this author in PubMed Google ScholarR. N. CaballeroYou can also search for this author in PubMed Google ScholarC. CaiYou can also search for this author in PubMed Google ScholarM. Z. ChenYou can also search for this author in PubMed Google ScholarZ. G. DaiYou can also search for this author in PubMed Google ScholarS. G. DjorgovskiYou can also search for this author in PubMed Google ScholarA. EsamdinYou can also search for this author in PubMed Google ScholarH. Q. GanYou can also search for this author in PubMed Google ScholarP. GuhathakurtaYou can also search for this author in PubMed Google ScholarJ. L. HanYou can also search for this author in PubMed Google ScholarL. F. HaoYou can also search for this author in PubMed Google ScholarY. X. HuangYou can also search for this author in PubMed Google ScholarP. JiangYou can also search for this author in PubMed Google ScholarC. K. LiYou can also search for this author in PubMed Google ScholarD. LiYou can also search for this author in PubMed Google ScholarH. LiYou can also search for this author in PubMed Google ScholarX. Q. LiYou can also search for this author in PubMed Google ScholarZ. X. LiYou can also search for this author in PubMed Google ScholarZ. Y. LiuYou can also search for this author in PubMed Google ScholarR. LuoYou can also search for this author in PubMed Google ScholarY. P. MenYou can also search for this author in PubMed Google ScholarC. H. NiuYou can also search for this author in PubMed Google ScholarW. X. PengYou can also search for this author in PubMed Google ScholarL. QianYou can also search for this author in PubMed Google ScholarL. M. SongYou can also search for this author in PubMed Google ScholarD. SternYou can also search for this author in PubMed Google ScholarA. StocktonYou can also search for this author in PubMed Google ScholarJ. H. SunYou can also search for this author in PubMed Google ScholarF. Y. WangYou can also search for this author in PubMed Google ScholarM. WangYou can also search for this author in PubMed Google ScholarN. WangYou can also search for this author in PubMed Google ScholarW. Y. WangYou can also search for this author in PubMed Google ScholarX. F. WuYou can also search for this author in PubMed Google ScholarS. XiaoYou can also search for this author in PubMed Google ScholarS. L. XiongYou can also search for this author in PubMed Google ScholarY. H. XuYou can also search for this author in PubMed Google ScholarR. X. XuYou can also search for this author in PubMed Google ScholarJ. YangYou can also search for this author in PubMed Google ScholarX. YangYou can also search for this author in PubMed Google ScholarR. YaoYou can also search for this author in PubMed Google ScholarQ. B. YiYou can also search for this author in PubMed Google ScholarY. L. YueYou can also search for this author in PubMed Google ScholarD. J. YuYou can also search for this author in PubMed Google ScholarW. F. YuYou can also search for this author in PubMed Google ScholarJ. P. YuanYou can also search for this author in PubMed Google ScholarB. B. ZhangYou can also search for this author in PubMed Google ScholarS. B. ZhangYou can also search for this author in PubMed Google ScholarS. N. ZhangYou can also search for this author in PubMed Google ScholarY. ZhaoYou can also search for this author in PubMed Google ScholarW. K. ZhengYou can also search for this author in PubMed Google ScholarY. ZhuYou can also search for this author in PubMed Google ScholarJ. H. ZouYou can also search for this author in PubMed Google ScholarContributionsH.X., J.R.N. and P.C. led the data analysis. K.J.L., W.W.Z., S.D. and B.Z. coordinated the observational campaign, cosupervised data analyses and interpretations, and led the paper writing. J.C.J. conducted the polarization and RM measurements. B.J.W., J.W.X., C.F.Z. and K.J.L. performed the timing analysis, periodicity search, DM measurement, burst searching and Faraday conversion measurement. Y.P.M. contributed to the searching software development. R.N.C., M.Z.C., L.F.H., Y.X.H., Z.Y.L., Z.X.L., Y.H.X. and J.P.Y. performed software testing. D.J.Z., Y.K.Z., P.W., Y.F., C.H.N., F.Y.W., X.F.W. and S.B.Z. contributed to radio data analysis. P.C., S.D., H.F., A.V.F., E.W.P., T.G.B., S.G.D., P.G., D.S., A.S., W.K.Z. and A.E. contributed to the optical observations and data reduction; A.V.F. also edited the manuscript in detail. P.C., S.D., H.F. and Y.L. contributed to analysing and interpreting the optical data. P.J., H.Q.G., J.L.H., H.L., L.Q., J.H.S., R.Y., Y.L.Y., D.J.Y. and Y.Zhu. aided with the FAST observations. J.L.H., D.L., M.W. and N.W. helped with observation coordination. K.J.L., B.Z., D.Z.L., W.Y.W., R.X.X., W.L., Y.P.Y., W.F.Y., Z.G.D. and R.L. provided theoretical discussions. C.C., C.K.L., X.Q.L., W.X.P., L.M.S., S.X., S.L.X., J.Y., X.Y., Q.B.Y., B.B.Z., S.N.Z., J.H.Z. and Y.Zhao contributed to the high-energy observations and data analyses.Corresponding authorsCorrespondence to K. J. Lee, W. W. Zhu, S. Dong or B. Zhang.Ethics declarations Competing interests The authors declare no competing interests. Peer review Peer review information Nature thanks Shami Chatterjee and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Additional informationExtended datais available for this paper at https://doi.org/10.1038/s41586-022-05071-8.Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.Extended data figures and tablesExtended Data Fig. 1 Temporal variations of extra physical parameters.a, Shape parameter (k) of Weibull distribution in event-rate inference. The error bar is at 68% confidence level. b,c, Daily burst energy and DM, in which the violin symbol indicates the distribution function, the green shaded strips indicate the 95% upper and lower bounds and the solid black curve is the median.Extended Data Fig. 2 Fluence, equivalent width and energy distribution for detected bursts.a,b, Cumulative distribution and histogram of the burst fluence; the dashed vertical red line at 53 mJy ms indicates the 95% completeness threshold. c, The 2D distribution of fluence and burst width. d, Histogram of burst width. e,f, Cumulative distribution and histogram of FRB 20201124A burst energy; the dashed vertical black line at 2 × 1036 erg indicates 95% completeness assuming a burst bandwidth of 185 MHz, the median of the burst bandwidths. The broken power law fit to the cumulative distribution of energy is the solid black curve, with the break point at 1.1 × 1038 erg indicated by a dot-dashed vertical line.Extended Data Fig. 3 Waiting time distribution of FRB 20201124A.a, The best fit using two log-normal functions (the blue curve), in which the two log-normal distributions peak at 39 ms and 106.7 s. b, The best fit (blue curve) using three log-normal functions, which are indicated with the dashed-line curves, peaking at 39 ms, 45.1 s and 162.3 s.Extended Data Fig. 4 Apparent RM variation within individual bursts.RM curve with 95% confidence level error bars (a), polarization profiles (b) and dynamic spectra (c). Bursts are dedispersed using corresponding structure-optimized DM values.Extended Data Fig. 5 RM index.a, Histogram of normalized RM index deviation defined as (β − 2)/σβ, in which σβ is the uncertainty of β with 68% confidence leve
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Cosmology & The Universe
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Astronomers have made the most detailed map ever of mysterious dark matter using the universe’s very first light, and the "groundbreaking" image has possibly proved Einstein right yet again.
The new image, made using 14 billion-year-old light from the turbulent aftermath of the Big Bang, shows the enormous matter tendrils that formed not long after the universe exploded into being. It turns out the shapes of these tendrils are remarkably similar to those predicted using Einstein's theory of general relativity.
The new result contradicts previous dark matter maps that suggested the cosmic web — the gigantic network of crisscrossing celestial superhighways paved with hydrogen gas and dark matter that spans the universe — is less clumpy than Einstein's theory predicted. The astronomers presented their findings April 11 at the Future Science with CMB x LSS conference at Japan's Yukawa Institute for Theoretical Physics.
"We've made a new mass map using distortions of light left over from the Big Bang," Mathew Madhavacheril (opens in new tab), a cosmologist at the University of Pennsylvania, said in a statement (opens in new tab). "Remarkably, it provides measurements that show that both the 'lumpiness' of the universe, and the rate at which it is growing after 14 billion years of evolution, are just what you'd expect from our standard model of cosmology based on Einstein's theory of gravity."
Scientists think that the universe that formed after the Big Bang teemed with matter as well as antimatter particles, which are identical to their matter counterparts but with opposite electrical charges.
Because matter and antimatter annihilate each other when they collide, if both were made in equal measure, all of the universe's matter should have been annihilated. However, the rapidly expanding fabric of space-time, along with some helpful quantum fluctuations, kept pockets of the universe's primordial plasma intact.
Then, according to the rules set out by Einstein's theory of relativity, gravity compressed and heated these plasma pockets so that sound waves — called baryon acoustic oscillations — rippled outward from the clumps at half the speed of light. These gigantic waves pushed out matter that hadn't already been sucked in on itself, creating the infant cosmic web: a series of thin films surrounding countless cosmic voids, like a nest of soap bubbles in a sink.
Once this matter cooled, it coalesced into the first stars, which pooled into matter-rich galaxies at the meeting points of the web's tangled strands.
But in the past, astronomers studying the cosmic web found what seemed to be a massive discrepancy — the matter was significantly more evenly distributed and less lumpy than expected. It was an ominous sign that existing cosmological models were missing important physics.
To dig into this apparent discrepancy, the researchers turned to the U.S. National Science Foundation's (NSF) Atacama Cosmology Telescope (ACT) in Chile, which scanned a quarter of the entire night sky from 2007 to 2022. Using its incredibly sensitive microwave detector, the telescope picked up light from the cosmic microwave background radiation (CMB) — the universe's very first light made just 380,000 years after the Big Bang — and used a process called gravitational lensing to map the concentrations of matter in the CMB.
Gravitational lensing is a phenomenon in which light moving through a region of space-time warped by powerful gravitational fields travels, in a curve — warping and twisting through a gigantic funhouse mirror until it emerges as a stretched-out arc called an Einstein ring. Gravitational lensing can detect dark matter, which makes up 85% of the universe's matter but cannot be directly observed.
The new map contradicted previous ones made with visible light from galaxies, and showed that Einstein's original theory was far more accurate than first thought.
What this means for our overall view of the cosmos' early evolution is still too early to say, but the researchers suggest that additional maps made using the ACT's data and fresh observations from the Simons Observatory — an under-construction Atacama Desert telescope that can scan the sky 10 times as fast as ACT — could finally resolve the perplexing cosmic mystery.
Ben Turner is a U.K. based staff writer at Live Science. He covers physics and astronomy, among other topics like tech and climate change. He graduated from University College London with a degree in particle physics before training as a journalist. When he's not writing, Ben enjoys reading literature, playing the guitar and embarrassing himself with chess.
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Cosmology & The Universe
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Ahead of the biggest premiere the world of astronomy has ever seen, NASA has published the cosmic A-list that will be appearing through the lens of its colossal new space telescope.And it's not just stars. There are galaxies, a planet too, and what promises to be the deepest view back in time that humanity has ever been able to achieve.
On Tuesday, the first images from the $10bn James Webb Space Telescope (JWST) will be shared with the world.Only a handful of the thousands of scientists and engineers who are working on the project have seen them. But the words "spectacular," and "beautiful," are being whispered among those who have.In a teaser ahead of the main release, NASA, the European and Canadian Space Agencies, which collaborated on the JWST, published a list of the five places in the universe that have been imaged by the telescope first. The locations are not exactly household names, but they have been carefully picked to showcase the capabilities of the new infrared telescope and its enormous 6.5 metre gold-plated mirror. Image: Carina Nebula. Pic: NASA First is the Carina Nebula, a 50 light-year-wide cloud of dust and stars 1000 light years from earth. It's one of the most beautiful objects in our galaxy. But it's also important for understanding how we came to exist. The colossal cloud of dust and gas is one of the most active star-forming regions discovered so far. It's likely our solar system formed in a place just like it. More from Science & Tech NASA criticises Russia for using space station to stage propaganda photographs Global wheat production can be doubled to feed millions and save land, say scientists Facebook accused of secretly saving deleted Messenger data and sharing it with police Astrophysicist Prof Martin Barstow at the University of Leicester said: "Infrared allows you to penetrate through that dust and gas."It will give us a completely new perspective."Star-forming regions, are more than just scientifically interesting, according to Dr Jeffery Kargel of the Planetary Science Institute in Tucson, Arizona."They are not just beautiful, but they are philosophically mind-blowing and even spiritually stirring when pondering the processes of creation and destruction, and the near-certain origins of life in many, many planets around many stars in the nebula."Arguably the most mind-blowing target is one little-known outside the field of astronomy. Image: SMACS 0723. Pic: Space Telescope Science Institute A region called SMACS 0723, where massive clusters of distant galaxies act to bend light due to their huge gravity. This "gravitational lens" brings the very earliest light in the universe into view.We haven't been able to see it before because the light is in the infrared spectrum - beyond the optics of the Hubble Space Telescope and invisible through our dusty atmosphere on Earth.The prize, said Prof Barstow is "first light": the potential JWST has to capture the very earliest light in the universe which came into being about 400 million years after the Big Bang."Webb is the only tool we have to do this," said Prof Barstow.Will JWST be able to make out any objects in the infrared gloom? We'll have to wait to find out.An entirely new view of a group of colliding galaxies called the Stephan's Quintet will feature, as well as the "cosmic smoke ring" left by an exploded star called the Southern Ring Nebula. Image: Stephan's Quintet. Pic: NASA Image: The 'cosmic smoke ring' left by an exploded star called the Southern Ring Nebula. Pic: NASA The final target is miniscule compared to the others. A planet called WASP-96-b, more than 1000 light years from Earth, orbiting a star very like our own Sun.It is hoped that JWST's measurements of this planet will prove its capabilities as a tool for seeking life elsewhere in the universe."This will not be a visual spectacle, but it will be a scientific treasure," said Dr Kargel.JWST will be able to study the chemical make-up of the planet's atmosphere in unprecedented detail by imaging it as it passes in front of its star.Don't get too excited - WASP-96-b is a Jupiter-like planet very close to its star so almost certainly scorching and lifeless.These obscure objects in the night sky may leave quite a lot of people cold. But excitement among astronomers, cosmologists and planetary scientists ahead of Tuesday's big reveal is palpable."Strap your brain in, batten down the hatches, and wait for your mind to be blown. It will be a Category 5," said Dr Kargel.
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Cosmology & The Universe
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GREENBELT, Md. (AP) — NASA on Tuesday unveiled a new batch of images from its new powerful space telescope, including a foamy blue and orange shot of a dying star.The first image from the $10 billion James Webb Space Telescope was released Monday at the White House — a jumble of distant galaxies that went deeper into the cosmos than humanity has ever seen.The four additional photos released Tuesday included more cosmic beauty shots. With one exception, the latest images showed parts of the universe seen by other telescopes. But Webb’s sheer power, distant location off Earth and use of the infrared light spectrum showed them in new light.“Every image is a new discovery and each will give humanity a view of the humanity that we’ve never seen before,” NASA Administrator Bill Nelson said Tuesday, rhapsodizing over images showing “the formation of stars, devouring black holes.”Webb’s use of the infrared light spectrum allows the telescope to see through the cosmic dust and “see light from faraway light from the corners of the universe,” he said.“We’ve really changed the understanding of our universe,” said European Space Agency director general Josef Aschbacher. The European and Canadian space agencies joined NASA in building the powerful telescope.On tap Tuesday: — Southern Ring Nebula, which is sometimes called “eight-burst.” About 2,500 light-years away, it shows an expanding cloud of gas surrounding a dying star. A light-year is 5.8 trillion miles. — Carina Nebula, one of the bright stellar nurseries in the sky, about 7,600 light-years away.— Five galaxies in a cosmic dance, 290 million light-years away. Stephan’s Quintet was first seen 225 years ago in the constellation Pegasus.— A blueish giant planet called WASP-96b. It’s about the size of Saturn and is 1,150 light-years away. A gas planet, it’s not a candidate for life elsewhere but a key target for astronomers.The images were released one-by-one at an event at NASA’s Goddard Space Center that included cheerleaders with pompoms the color of the telescope’s golden mirrors.The world’s biggest and most powerful space telescope rocketed away last December from French Guiana in South America. It reached its lookout point 1 million miles (1.6 million kilometers) from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool. Webb is considered the successor to the highly successful, but aging Hubble Space Telescope. ___The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
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Cosmology & The Universe
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Many of us tend to ponder about the universe when looking at the night sky on a beautiful evening. We all know the type of questions that emerge during these occasions. Interestingly enough, even seemingly straightforward ones like 'why is the night sky black?' and 'how large is the universe?' can sparkle a deep conversation. These questions come naturally to us humans, and we have probably contemplated them since ancient history.The most commonly heard questions relate to distance: 'How far away is the sun?' 'how far away is the moon?' how far away is that star? Etc. It is challenging to convey these types of astronomical distances as they compare to nothing else we are used to on a human scale. In this article, we will attempt to put these vast distances into perspective and provide you with some entertaining insights along the way. Image Credit: Denis Belitsky via Shutterstock / HDR tune by Universal-Sci What is the distance to the Moon?Perhaps the distance to our Moon is easiest to describe; after all, it is the closest celestial body to Earth. The actual distance between Earth and the Moon varies throughout the Moon's orbit, but the Moon's average distance is approximately 384,402 kilometers. A distance of 380,000 kilometers is on the edge of being conceivable on a human scale. If you own a car, have a look at your odometer for some perspective. We estimate that it would take the average person about 10 to 20 years to achieve a 'mileage' comparable to the Moon and Earth's average distance. Quite some way to reach the Moon, one would think, but let's immediately put this in perspective by comparing it to the distance to Mars when it makes its closest approach to Earth at an approximate distance of 54,000,000 kilometers (142 times the distance of the moon). Dr. James O'Dongoghue, a familiar guest on our Twitter feed, has put this neatly into context in the image below. Keep in mind that the distances on display here are to scale, but the planetary bodies have been enlarged 20 times (otherwise, they wouldn't be visible) Image Credit: James O’Donoghue / NASA Looking at this 'best-case scenario' image, it immediately becomes clear why going to mars is a tad more challenging than visiting the Moon. In fact, the distance to Mars is so vast that communication works with a delay of several minutes, while the lag between Earth and the Moon is expressed in mere seconds, not minutes. What is the distance from the Earth to the sun?Let's take another metaphorical step back and have a look at the distance between the Sun and Earth. On average, you will have to travel approximately 149,597,870 kilometers to reach the Sun. At these distances, we start encountering numbers that are hard to comprehend on their own accord. Conveniently, astronomers defined a unit of length specifically usable at this scale, called the Astronomical Unit or AU. One AU is 149,597,870 kilometers which is roughly equal to the distance from Earth to the Sun. Described in this unit of length, the distance to Mars is 0.37 AU at the closest approach. The astronomical unit is particularly serviceable in describing the distance to objects outside the asteroid belt. Saturn, for example, is 1,201,336,738 kilometers away from Earth at its closest approach, which is 8.03 AU. Pluto, a more distant dwarf planet, is over 4 billion kilometers away at its closest approach, more neatly defined as 28.68 AU. 4 billion kilometers sounds a lot more abstract than a more comprehensible 28 times the distance of the Sun. You could also use another unit of length to articulate the Sun's distance, namely the light-second. Light travels at a speed of 299,792,458 meters per second through a vacuum (roughly 300,000 km/s or 186,000 mi/s). As such, light originating from the Sun takes about 499 seconds to reach our planet. Stated differently, the distance to the Sun is 499 light-seconds. Interesting Fact: Although the 'speed of gravity' is assumed to be infinite in Newtonian physics, it is actually the same as the speed for light. Meaning that if the Sun were to disappear suddenly, we would only notice it on Earth after about 8 minutes.How far away is the closest star?Let's zoom out further to a tiny star called Proxima Centauri, our closest (known) neighbor star. Although it is located relatively nearby, it has only been discovered quite recently (1915) due to its small size. Proxima Centauri is part of a so-called 'triple star system' called Alpha Centauri. It is located at an approximate distance of 40,208,000,000,000 kilometers (40.2 trillion km or 268,770 AU). A distance so vast that even using Astronomical Units to get perspective doesn't make a whole lot of sense anymore.At this scale, the most logical unit of length to use to describe distance would be the light-year. A light-year is defined as the distance light travels in a vacuum in one year, which is 9.46 trillion kilometers. Proxima Centauri is about 4.2 light-years away from the Sun. Our stellar neighborhood - Image Credit: Andrew Z. Colvin via Wikimedia Commons / (CC BY-SA 4.0) - (Click on image to enlarge) One additional unit of length that makes sense at these distances is the Parsec. The Parsec was famously misused in Star Wars: A New Hope, where Han Solo claimed that his ship made the Kessel Run in less than 12 parsecs, mistaking the Parsec as a unit of time, not a unit of distance. A parsec is about 3.26 light-years or 206,000 AU. Proxima Centauri is located roughly 1.3 Parsec away from the Sun. The main reason why Parsec, a word derived from the parallax of one arcsecond, exists is to make calculations of astronomical distances from raw observational data more convenient for astronomers. However, it can also be helpful to put large distances in perspective. You could think of parsecs as distances between our Sun and the nearest neighboring star, given their close similarity.How far away is the closest galaxy?Jumping from our stellar neighborhood to our galactic neighborhood is a colossal leap. The closest galaxy to us is the Canis Major Dwarf Galaxy, at 236,000,000,000,000,000 kilometers (25,000 light-years) from the Sun. The supposed small galaxy contains a relatively high percentage of red giants and is thought to have an estimated one billion stars overall. Some researchers dispute the galaxy claim that it is actually part of our own Milky Way Galaxy.A distance of 1,000 parsecs (3,262 ly) is denoted by the kiloparsec. Astronomers generally use kiloparsecs to express space between parts of a galaxy or within groups of galaxies. It makes more considerable distances manageable. Using this unit of length, the Canis Major Dwarf Galaxy 'stands' at a distance of 7.7 kiloparsecs. Some perspective: our Milky Way has an estimated (visible) diameter of 150,000 light-years or 46 kiloparsecs. These figures make it understandable why it might be hard to distinguish the Canis Majord Dwarf Galaxy as a separate entity. Let's skip ahead to the largest galaxy in our local group, the Andromeda Galaxy, a gorgeous barred spiral galaxy containing an estimated 1 trillion stars (2x to 10x as many as the Milky Way). It is located approximately 2,500,000 light-years or 770 kiloparsecs from Earth. The Andromeda Galaxy - Image Credit: PavelSmilyk via iStock/Getty Images - HDR tune by Universal-Sci Interesting Fact: The Andromeda Galaxy is approaching the Milky-Way Galaxy on a collision course with a mind-bending speed of 396,000 kilometers per hour, as indicated by blueshift measurements. At this speed, the galaxies are predicted to clash in about 4.5 billion years. Let's have a look at an overview of our galactic neighborhood akin to that of our stellar neighborhood earlier. Our galactic neighborhood consists of the so-called 'Local Group' and has a diameter of roughly 10,000,000 light-years (or 3,000 kiloparsecs). The 'Local Group' consists of two collections of galaxies in a "dumbbell" shape: the Milky Way and its satellites construct one lobe while the aforementioned Andromeda Galaxy and its satellites compose the other.At this scale, even the kiloparsec becomes a bit messy to use. That is why astronomers commonly express the distances between neighboring galaxies and galaxy clusters in megaparsecs (Mpc). A megaparsec is one million parsecs or approximately 3,260,000 light-years. Using this unit of length, the diameter of the Local Group is about 3 Mpc. Our galactic neighborhood (Local Group) - Image Credit: Andrew Z. Colvin via Wikimedia Commons (CC BY-SA 4.0) - (Click on image to enlarge) The scale of galaxy superclusters in perspectiveLet's zoom out even further and have a look at galaxy superclusters. A galaxy supercluster is a gigantic structure that commonly contains thousands of galaxies. (Each containing billions to trillions of stars).Our local group is part of the Virgo Supercluster, a galactic supercluster that is estimated to contain more than 47,000 galaxies! This is not where it ends though, in 2014, astronomers determined that the Virgo Supercluster is actually a component of an even larger supercluster called Laniakea. Laniakea is Hawaiian for open skies or immense heaven a befitting name for this stupendously large structure. The Laniakea supercluster is estimated to contain 100,000 to 150,000 galaxies. Research indicates that the Laniakea Supercluster is not gravitationally connected; it will probably scatter rather than continue to sustain itself. The Laniakea supercluster with our local group at the center - Image Credit: Andrew Z. Colvin via Wikimedia Commons / Edited by Universal-Sci for emphasis on the Local Group (CC BY-SA 4.0) - (Click on image to enlarge) With an estimated diameter of 500,000,000 light-years or 153 megaparsecs, it is almost impossible to comprehend—Nonetheless, let's attempt to draw some form of perspective. If we were to discover intelligent life in the outer reaches of our own supercluster, an attempt to connect them would take millions of years (at least with contemporary communication methods, bound by the laws of physics). When our signal would finally reach its destination, we ourselves might not even exist anymore. Naturally, 'lightspeed lag' works both ways. For example, light from our solar system would take nearly 70 million years to reach Galaxy NGC 2525, another stunning barred spiral galaxy located in the constellation Puppis. If intelligent life exists in NGC 2525, it would consequently see Earth as it was 70 million years ago. There would be no sign of human life; instead, they would observe the latter stages of the cretaceous epoch with dinosaurs still roaming the planet.Cosmic supermassive structuresAlthough the Laniakea supercluster is an exceptionally enormous structure, even larger 'cosmic supermassive structures' have been identified largest, among which is the so-called Hercules–Corona Borealis Great Wall. Discovered in 2013, it is (currently) the largest known structure in the observable universe. The wall has an estimated mean size of 10 billion (10,000,000,000 light-years). If we're honest, at this scale, it is no longer possible to offer a meaningful perspective other than that the gigaparsec is often used by astronomers to convey these mind-melting distances. One gigaparsec (Gpc) is 1 billion parsecs / 3.26 billion light-years. Expressed in this unit of length, the wall's mean size is about 3 Gpc. The Hercules-Corona Borealis Great Wall is so vast that it covers one 5th of the distance to the horizon of the observable universe. An artist’s impression of the Hercules–Corona Borealis Great Wall - Image Credit: Pablo Carlos Budassi via Wikimedia Commons / edited for size by Universal-Sci (CC BY-SA 4.0) The observable universeTaking a metaphorical step back once more and we have finally reached the limits of what we can see. The observable universe is a globular section of the universe containing all matter that can be observed from Earth for this moment. This region is defined by the speed of light and the time light has had to reach us since the big bang. The observable universe has a diameter of 93,000,000,000 light-years or 28,5 gigaparsecs. Most recent assessments based on data from NASA's interplanetary space probe new horizons predict that the total number of galaxies in the visible universe reaches several hundreds of billions. Due to unknown reasons (commonly referred to as dark energy), the universe is expanding at an increasing rate. In due course, all presently observable objects will seem to freeze in time and ultimately disappear from our horizon. That is, of course, unless the properties of dark energy will change over time. The observable universe and our place within it - Image Credit: Andrew Z. Colvin via Wikimedia Commons edited by Universal-Sci for further emphasis on relevant structures (CC BY-SA 4.0) - (Click on image to enlarge)
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Cosmology & The Universe
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WASHINGTON -- A stellar nursery where stars are born, interactions between galaxies and a unique view of an exoplanet are just some of the new cosmic images were shared Tuesday.After decades of waiting, it's finally time for the world to see the first images taken by the most powerful space telescope ever -- the James Webb Space Telescope.Development of the world's premier space observatory began in 2004, and after years of delays, the telescope and its massive gold mirror finally launched on December 25.The images are worth the wait -- and they will forever change the way we see the universe.President Joe Biden released one of Webb's first images on Monday, and it is "the deepest and sharpest infrared image of the distant universe to date," according to NASA. The rest of the high-resolution color images made their debut on Tuesday.MORE: President Biden reveals the Webb Telescope's stunning first imageThe space observatory can investigate the mysteries of the universe by observing them through infrared light, which is invisible to the human eye.Webb will peer into the very atmospheres of exoplanets, some of which are potentially habitable, and it could uncover clues in the ongoing search for life outside of Earth.The telescope will also look at every phase of cosmic history, including the first glows after the big bang that created our universe and the formation of the galaxies, stars and planets that fill it today.Now, Webb is ready to help us understand the origins of the universe and begin to answer key questions about our existence, such as where we came from and if we're alone in the cosmos.The first imagesThe first image, released on Monday, shows SMACS 0723, where a massive group of galaxy clusters act as a magnifying glass for the objects behind them. Called gravitational lensing, this created Webb's first deep field view that includes incredibly old and faint galaxies.Some of these distant galaxies and star clusters have never been seen before. The galaxy cluster is shown as it appeared 4.6 billion years ago.The image, taken by Webb's Near-Infrared Camera, is composed of images taken at different wavelengths of light over a collective 12.5 hours. Deep field observations are lengthy observations of regions of the sky that can reveal faint objects.Galaxies collide in Stephan’s Quintet, pulling and stretching each other in a gravitational dance. In the mid-infrared view here, see how Webb pierces through dust, giving new insight into how interactions like these may have driven galaxy evolution in the early universe. pic.twitter.com/3P15LMCCOH— NASA Webb Telescope (@NASAWebb) July 12, 2022Webb's other primary targets for the first image release included the Carina Nebula, WASP-96 b, the Southern Ring Nebula and Stephan's Quintet.Webb's study of the giant gas planet WASP-96 b is the most detailed spectrum of an exoplanet to date. The spectrum includes different wavelengths of light that reveal new information about the planet and its atmosphere. Discovered in 2014, WASP-96 b is located 1,150 light-years from Earth. It has half the mass of Jupiter and completes an orbit around its star every 3.4 days.Webb's spectrum includes "the distinct signature of water, along with evidence for clouds and haze, in the atmosphere surrounding a hot, puffy gas giant planet orbiting a distant Sun-like star," according to NASA.The observation demonstrates "Webb's unprecedented ability to analyze atmospheres hundreds of light-years away," according to NASA.In the future, Webb will capture actual images of known exoplanets while also searching for unknown planets, said Knicole Colón, Webb deputy project scientist for exoplanet science at NASA's Goddard Space Flight Center, during a news conference. And the spectrium of WASP-96 b is "barely scratching the surface of what we're going to learn."Colón anticipates that scientists will determine just how much water is in the exoplanet's atmosphere.The Southern Ring Nebula, also called the "Eight-Burst," is 2,000 light-years away from Earth. This large planetary nebula includes an expanding cloud of gas around a dying star. Webb helped reveal previously hidden details about the nebula, which is a shell of gas and dust released by the dying star. The nebula's second star can be seen in the Webb image, as well as how the stars shape the gas and dust cloud.The second star is surrounded by dust while the brighter star, at an earlier stage of evolution, will release its own cloud of gas and dust later on. As the two stars orbit one another, they effectively "stir" the gas and dust, resulting in the patterns seen in the image.The insights from images like this could help astronomers to unlock how stars change their environments as they evolve. Multi-colored points of light in the background represent galaxies.The space telescope's view of Stephan's Quintet shows the way galaxies interact with one another. This compact galaxy group, first discovered in 1787, is located 290 million light-years away in the constellation Pegasus. Four of the five galaxies in the group "are locked in a cosmic dance of repeated close encounters," according to a NASA statement.If you've ever watched "It's a Wonderful Life," you've seen Stephan's Quintet. Now, Webb has revealed the galactic grouping in a new mosaic which is the telescope's largest image to date."The information from Webb provides new insights into how galactic interactions may have driven galaxy evolution in the early universe," according to NASA.The Stephan's Quintet image provides a rare glimpse into how galaxies can trigger star formation in one another when they interact, as well as outflows driven by a black hole at a new level of detail.The gravitational dance between these galaxies can be seen through tails of gas, dust and stars and even shock waves as one of the galaxies pushes through the cluster.Located 7,600 light-years away, the Carina Nebula is a stellar nursery, where stars are born. It is one of the largest and brightest nebulae in the sky and home to many stars much more massive than our sun.Now, its "Cosmic Cliffs" are revealed in an incredible new Webb image.Webb's ability to see through cosmic dust has revealed previously invisible areas of star birth within the nebula, which could provide new insight on the formation of stars. The earliest stages of star formation are harder to capture -- but something Webb's sensitivity can chronicle.What looks like a landscape in the image is really a massive gaseous cavity with "peaks" reaching 7 light-years high."The cavernous area has been carved from the nebula by the intense ultraviolet radiation and stellar winds from extremely massive, hot, young stars located in the center of the bubble, above the area shown in this image," according to NASA. And what looks like "steam" rising off the "mountains" is hot, energetic gas and dust.The targets were selected by an international committee, including members from NASA, the European Space Agency, the Canadian Space Agency and the Space Telescope Science Institute in Baltimore.A long future of observationThe mission, originally expected to last for 10 years, has enough excess fuel capability to operate for 20 years, according to NASA Deputy Administrator Pam Melroy.These will be just the first of many images to come from Webb over the next two decades, which promises to fundamentally alter the way we understand the cosmos.While some of what Webb could reveal has been anticipated, the unknowns are just as exciting to scientists."We don't know what we don't know yet," said Amber Straughn, Webb deputy project scientist for communications at NASA Goddard. "I think it's true that every time we launch a revolutionary instrument into space, like with Hubble, we learn things that completely surprise us but do cause us to sort of change our fundamental understanding of how the universe works."Hubble's 31 years have yielded a wealth of discoveries that couldn't be anticipated, and the scientific community views Webb and its capabilities in the same way.When comparing Webb's first images to other breakthroughs in astronomy, Webb program scientist and NASA Astrophysics Division chief scientist Eric Smith compared it to seeing Hubble's images after the telescope was repaired and everything snapped into focus."A lot of people sometimes see pictures of space and they think it makes them feel small," Smith said. "When I see these pictures, they make me feel powerful. A team of people can make this unbelievable instrument to find out things about the universe revealed here, and just seeing that pride in the team, and pride in humanity, that when we want to, we can do that.""The universe has [always] been out there," said Jane Rigby, Webb operations project scientist at NASA Goddard. "We just had to build a telescope to go see what was there. Yeah, very similar feeling of, maybe, people in a broken world managing to do something right and to see some of the majesty that is out there."The-CNN-Wire ™ & © 2022 Cable News Network, Inc., a WarnerMedia Company. All rights reserved.
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Cosmology & The Universe
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Astronomers use the brightness of a type of exploding star known as a supernova type IA (seen here as bright blue dot to the left of a remote spiral galaxy) to determine the age and expansion rate of the universe. New calibrations of the luminosity of nearby stars, observed by NIST researchers, could help astronomers refine their measurements. Credit: NASA, ESA, J. DePasquale (STScI), M. Kornmesser and M. Zamani (ESA/Hubble), A. Riess (STScI/JHU) and the SH0ES team, and the Digitized Sky Survey A picture may be worth a thousand words, but for astronomers, simply recording images of stars and galaxies isn't enough. To measure the true size and absolute brightness (luminosity) of heavenly bodies, astronomers need to accurately gauge the distance to these objects. To do so, the researchers rely on "standard candles"—stars whose luminosities are so well known that they act like light bulbs of known wattage. One way to determine a star's distance from Earth is to compare how bright the star appears in the sky to its luminosity. But even standard candles need to be calibrated. For more than a decade, scientists at the National Institute of Standards and Technology (NIST) have been working to improve the methods for calibrating standard stars. They observed two nearby bright stars, Vega and Sirius, in order to calibrate their luminosity over a range of visible-light wavelengths. The researchers are now completing their analysis and plan to release the calibration data to astronomers within the next 12 months.
The calibration data could aid astronomers who use more distant standard candles—exploded stars known as type Ia supernovas—to determine the age and expansion rate of the universe. (Comparing the brightness of remote type Ia supernovas to nearby ones led to the Nobel-prize winning discovery that the expansion of the universe is not slowing down, as expected, but is actually speeding up.)
Astronomers may be able to use the NIST calibrations of Vega and Sirius to better compare the brightness of nearby and faraway type Ia supernovas, leading to more accurate measurements of the expansion of the universe and its age.
In the ongoing NIST study, scientists observe the two nearby stars with a four-inch telescope they designed and placed atop Mount Hopkins in the desert of southern Arizona. John Woodward, Susana Deustua, and their colleagues have repeatedly observed the spectra, or colors, of light emitted by Vega (25 light-years away) and Sirius (8.6 light-years). One light-year, the distance that light travels through a vacuum is one year, is 9.46 trillion kilometers.
At the beginning and end of each observing night, the researchers tilt the telescope downwards so that they can compare the stellar spectra to that of an artificial star—a quartz lamp whose luminosity has been exactly measured and placed 100 meters from the telescope.
Before the scientists can directly make the comparisons, they must account for the effect of Earth's atmosphere, which scatters and absorbs some of the starlight before it can reach the telescope. Although light from the ground-based lamp does not travel through the full depth of the atmosphere, some of it is scattered by air during its short, horizontal journey to the telescope. To assess how much of the ground-based light is scattered from the lamp, the NIST team measures the relative ratio of power generated by a helium-neon laser at its output and 100 m away, at the site of the lamp.
To determine how much starlight is lost to the Earth's atmosphere, the researchers record the amount of starlight reaching the telescope as it points in different directions, peering through different thicknesses of the atmosphere during the night. Changes in the amount of light recorded by the telescope as the night progresses allow astronomers to correct for the atmospheric absorption.
Once Vega and Sirius are calibrated, astronomers can use those stars as steppingstones to calibrate the light from other stars. For instance, by using the same telescope, researchers can observe a set of slightly fainter stars—call them Set 2. The luminosity of those fainter stars can then be calibrated using Vega and Sirius as reference standards. The four-inch telescope on Mt. Hopkins in Arizona. Credit: J. Woodward/NIST Switching to a telescope large enough to observe both the newly calibrated Set 2, and a group of even fainter stars (call them Set 3), astronomers can calibrate the light from Set 3 in terms of Set 2. Astronomers can repeat the process as needed to calibrate light from extremely remote stars. In this way, astronomers will be able to transfer the NIST calibration of Vega and Sirius to stars that lie thousands to millions of light-years away.
Next year, Deustua and Woodward will move their small telescope, now back at NIST, to the European Southern Observatory's (ESO's) Paranal Observatory in the high-altitude desert of northern Chile. With drier climate than Mt. Hopkins, the Chilean site promises more clear nights to observe Sirius and Vega and less moisture to absorb or scatter the light. The telescope will reside on a mountaintop away from ESO's Very Large Telescope, a suite of four 8.2-m telescopes and four 1.2-m telescopes, so that the light from NIST's quartz lamp won't interfere with observations of distant galaxies.
The team also plans to expand its repertoire of bright nearby stars to include Arcturus (37 light-years), Gamma Crucis (89 light-years), and Gamma Trianguli Australis (184 light-years) and to observe stars at longer, infrared wavelengths. The recently launched James Webb Space Telescope and the Roman Space Telescope, set for launch by the end of the decade, are designed to examine the universe at these wavelengths.
The NIST researchers recently received seed money to build a larger telescope which could observe and calibrate fainter, more distant stars. That would allow astronomers to transfer the NIST calibration to remote standard candles more directly. Reducing the number of stepping stones between the stars observed by NIST and the stars astronomers are studying reduces calibration errors. Citation: Calibrating the luminosity of nearby stars to refine calculations of universe age and expansion (2022, September 23) retrieved 23 September 2022 from https://phys.org/news/2022-09-calibrating-luminosity-nearby-stars-refine.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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Cosmology & The Universe
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In recent years, astronomy has seen itself in a bit of crisis: Although we know that the Universe expands, and although we know approximately how fast, the two primary ways to measure this expansion do not agree. Now astrophysicists from the Niels Bohr Institute suggest a novel method which may help resolve this tension.
The Universe expands
We've known this ever since Edwin Hubble and other astronomers, some 100 years ago, measured the velocities of a number of surrounding galaxies. The galaxies in the Universe are "carried" away from each other by this expansion, and therefore recedes from each other.
The greater the distance between two galaxies, the faster they move apart, and the precise rate of this movement is one of the most fundamental quantities in modern cosmology. The number that describes the expansion goes by the name "the Hubble constant," appearing in multitude of different equations and models of the Universe and its constituents.
Hubble Trouble
To understand the Universe we must therefore know the Hubble constant as precisely as possible. Several methods exist to measure it; methods that are mutually independent but luckily give almost the same result.
That is, almost…
The intuitively easiest method to understand is, in principle, the same that Edwin Hubble and his colleagues used a century ago: Locate a bunch of galaxies, and measure their distances and speeds. In practise this is done by looking for galaxies with exploding stars, so-called supernovae. This method is complemented by another method that analyzes irregularities in the so-called cosmic background radiation; an ancient form of light dating back to shortly after the Big Bang.
The two methods -- the supernova method and the background radiation method -- always gave slightly different results. But any measurement comes with uncertainties, and a few years back the uncertainties were substantial enough that we could blame those for the disparity.
Nevertheless, as measurement techniques have improved, uncertainties have diminished, and we've now reached a point where we can state with a high degree of confidence that both cannot be correct.
The root of this "Hubble trouble" -- whether it is unknown effects systematically biasing one of the results, or if it hints at new physics yet to be discovered -- is currently one of astronomy's hottest topics.
Two methods
The expansion of the Universe is measured in "speed per distance," and is just over 20 km/s per million lightyears. That means that a galaxy located 100 million lightyears away recedes from us at 2,000 km/s, while another galaxy 200 million lightyears away recedes at 4,000 km/s.
But using supernovae to measure distances and velocities of galaxies yields 22.7 ± 0.4 km/s, while analyzing the background radiation of the Universe yields 20.7 ± 0.2 km/s.
It might sound pernickety to care about such a little disagreement, but for instance the number appears in the calculation of the age of the Universe, and the two methods yield an age of 12.8 and 13.8 billion years, respectively.
Crashing neutron stars may help with the answer
One of the greatest challenges lies in accurately determining the distances to galaxies. But in a new study, Albert Sneppen who is a PhD student in astrophysics at the Cosmic Dawn Center at the Niels Bohr Institute in Copenhagen, proposes a novel method for measuring distances, thereby helping to settle the ongoing dispute.
"When two ultra-compact neutron stars -- which in themselves are the remnants of supernovae -- orbit each other and ultimately merge, they go off in a new explosion; a so-called kilonova," Albert Sneppen explains. "We recently demonstrated how this explosion is remarkedly symmetric, and it turns out that this symmetry not only is beautiful, but also incredibly useful."
In a third study that has just been published, the prolific PhD student shows that kilonovae, despite their complexity, can be described by a single temperature. And it turns out that the symmetry and the simplicity of the kilonovae enable the astronomers to deduce exactly how much light they emit.
Comparing this luminosity with how much light reaches Earth, the researchers can calculate how far away the kilonova is. They have thereby obtained a novel, independent method to calculate the distance to galaxies containing kilonovae.
Darach Watson is an associate professor at the Cosmic Dawn Center and a co-author of the study. He explains: "Supernovae, which until now have been used to measure the distances of galaxies, don't always emit the same amount of light. Moreover, they first require us to calibrate the distance using another type of stars, the so-called Cepheids, which in turn also must be calibrated. With kilonovae we can circumvent these complications that introduce uncertainties in the measurements."
Confirms one of the two methods
To demonstrate its potential, the astrophysicists applied the method to a kilonova discovered in 2017. The result is a Hubble constant closer to the background radiation method, but whether the kilonova method can resolve the Hubble trouble, the researchers do not yet dare to state:
"We only have this one case study so far, and need many more examples before we can establish a robust result," Albert Sneppen cautions. "But our method at least bypasses some known sources of uncertainty, and is a very "clean" system to study. It requires no calibration, no correction factor."
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Cosmology & The Universe
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Astronaut Mike Massimino Webb Telescope More Than Pretty Pics ... Might Show Birth of the Universe!!! 7/12/2022 2:56 PM PT TMZ.com NASA's very high hopes for the James Webb Telescope go way beyond those stunning, out-of-this-world images you've seen -- astronaut Mike Massimino says it could literally redefine the universe for us. Mike joined TMZ live Tuesday, shortly after NASA released even more impressive photos of galaxies and stars forming billions of light-years away from Earth. He says scientists hope the telescope will achieve 2 major goals. NASA The first is trying to look back into stellar history as far as possible -- about 13.8 billion years ago -- to see the very first light created at the moment of the Big Bang!!! Meaning, it would no longer just be theory. Mind blowing, right??? Mike says the J-dub Telescope could also help us find other habitable planets. Now, he says there's no need to pack your bags -- we won't be able to hop one one of Elon Musk's rockets to get there, even IF we find such a planet. As we've told you, NASA released 4 new shockingly clear space images Tuesday, after unveiling an initial image on Monday ... which the space agency called the "the deepest, sharpest infrared image of the universe ever." Waiting for your permission to load the Instagram Media. As for the whole Big Bang Theory (actual science, not a TV sitcom) ... we had to ask Mike how the telescope's findings might challenge some people's view of religion. Having been in space himself, he had a very interesting take on that huge question.
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Cosmology & The Universe
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A brand new, detailed view of the universe that looks further back into space and time than ever before has been revealed in an extraordinary set of photos.NASA has released a full set of images from its James Webb Space Telescope, showing what is said to be the "deepest" and most detailed picture of the cosmos to date.
This new view of the universe is possible because the Webb is huge - with a mirror more than twice the size of the previously-used Hubble.It is the largest and most powerful telescope ever sent into space.NASA Administrator Bill Nelson said: "Every image is a new discovery and each will give humanity a view of the humanity that we've never seen before.'' The first image: cluster of distant galaxies The image above shows a deep field cluster of distant galaxies, as they looked billions of years ago. More on Nasa James Webb Telescope live updates: NASA reveals images that tell secrets of universe The Hubble Space Telescope: What are its greatest hits? NASA reveals picture of distant universe taken by James Webb Space Telescope - but why is it a big deal? Jane Rigby, who worked on the project, says this shows them from about the time the sun and earth formed.The image has a "sharpness and clarity" we've never had before, she says, and under a close-up, it is possible to see "individual clusters of stars forming, just popping up like popcorn".Although if it looks a bit familiar, it's because it was first revealed by NASA as a teaser yesterday.Sky's science and technology editor Tom Clarke says this is a long exposure photo of a tiny patch of the universe. Please use Chrome browser for a more accessible video player 'Jaws were on the floor' at NASA images "If you held out your arm outstretched with a grain of sand on your finger- that's the size of the patch of sky this image covers," he says.The second image: a giant planet This image is an analysis of the atmosphere of a giant planet called WASP-96 b, and is the first "spectrum analysis" of an exoplanet's atmosphere.Webb will take a number of "spectrum" photos in the coming months.This process involves spitting light into its component "colours" in order to show what a body is made of, how fast it is moving, or even what its temperature is.This analysis is of a giant gas planet located nearly 1,150 light-years from Earth, which orbits its star every 3.4 days.It has about half the mass of Jupiter, and its discovery was announced in 2014.NASA said: "Webb spotted the unambiguous signature of water, indications of haze & evidence for clouds (once thought not to exist there)!"The third image: a planetary nebula In this infrared image, we can see a planetary nebula caused by a dying star.It is nearly half a light-year in diameter and is located approximately 2,000 light-years away from Earth. A light-year is 5.8 trillion miles.The star can be seen expelling a large fraction of its mass.The Southern Ring Nebula, is sometimes also called "eight-burst".The fourth image: Stephan's Quintet This image is of a group of five galaxies, two of which are in the process of merging.It's a combination of mid-infrared and near-infrared images that reveals stars being born.Although called a "quintet" only four of the galaxies are truly interacting in a cosmic dance - the one on the left is actually in the foreground.The fifth image: cosmic cliffs of the Carina Nebula This stunning image shows us - for the first time - hundreds of stars that were previously completely hidden from our view.The Carina Nebula is a nearby (in space terms) star-forming region within our own Milky Way galaxy.The "cosmic cliffs" were previously pictured by Hubble's telescope, but this new view gives us a rare glimpse of stars in their earliest, rapid stages of formation.The near-infrared shows hundreds of stars and background galaxies, while the mid-infrared shows dusty planet-forming disks (in red and pink) around young stars.Telescope's missionA partnership of scientists and engineers was formed between NASA, the European Space Agency and the Canadian Space Agency - and for 20 years they worked to complete the £8.4bn telescope. Image: US President Joe Biden got a sneak-peek of the images yesterday Read more: Analysis: Why are these pictures such a big deal?The deepest view of the universe ever captured: NASA releases first image from new space telescope On Christmas Day, 2021, the Webb was launched and it reached its destination in solar orbit nearly 1 million miles from Earth a month later.Once there, the telescope underwent a months-long process to unfurl all of its components, including a sun shield the size of a tennis court, and to align its mirrors and calibrate its instruments.The universe has been expanding for 13.8 billion years, meaning the light from the first stars and galaxies has been "stretched" from shorter visible wavelengths to longer infrared ones. This is what allows Webb to see the universe in unprecedented new detail.These pictures are the first of millions the new telescope will produce over its 20-year lifetime.Each full-colour, high-resolution picture that was unveiled on Tuesday took weeks to render from raw telescope data.Watch-parties for the picture release took place all over the world including in the US, Canada, Israel, UK and Europe.
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Cosmology & The Universe
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Faster, better, stronger. A new phase of operations at the Large Hadron Collider — the world’s largest particle accelerator — is scheduled to start in a few weeks, just a day after the 10th anniversary of its greatest achievement so far: the discovery of the long sought-after Higgs boson.The collider’s reopening (it’s been closed since 2018) is an important event for global science, as what is generally considered one of the biggest science experiments ever conducted has already helped reveal important details about the fabric of reality.The Higgs discovery in July 2012 affirmed the Standard Model of Particle Physics, which still holds sway as the best explanation of how matter works. But scientists hope the latest LHC run will explain even greater mysteries of existence — including the invisible particles that make up dark matter, and just why there is anything here at all.“We’re now ready for Run 3,” said Rende Steerenberg, who heads beam operations for CERN, the international organization that runs the LHC — a vast hidden ring of tunnels and detector caverns built deep underground beneath fields, trees and towns on the border of France and Switzerland, over 5 miles across and more than 16 miles around. The LHC has been dormant for more than three years while it’s been upgraded with tens of millions of dollars worth of improvements — the upgraded facility will achieve energies of up to 13.6 trillion electron volts (TeV), compared to just 13 TeV in the previous run — and advanced detecting equipment to better examine the chaotic explosions inside the giant atom smasher. It’s now being tested at low-power, and the first experimental collisions of the third run will begin on July 5.The LHC uses giant magnets to accelerate beams of protons and atomic nuclei in opposite directions around the underground ring, and then brings them together for a series of high-energy collisions at near the speed of light. This achieves energies that haven’t been seen since the first split seconds of the universe after the Big Bang.Studying the remnants of such collisions can tell scientists which particles formed in them, even for just the tiniest fraction of a second. Scientists theorize that the thousands of collisions performed inside the LHC every hour will produce at least some of the exotic particles they are looking for.Steerenberg explained that latest LHC upgrade is a half-step before better detecting methods are installed after 2027, when the LHC will operate at full capacity as the “High Luminosity” LHC — its fourth and final incarnation before an even larger particle accelerator, the Future Circular Collider, comes online after 2040.The LHC is a crucial tool for physicists. Several unsolved problems remain in the theories meant to explain physical reality — some of which date back to the early 20th century — and scientists have suggested a variety of ideas for how it all fits together. Some of those ideas work on paper, but require the existence of certain particles with particular qualities. The LHC is the most advanced particle accelerator built so far, and was designed to look for those particles and measure them. The results are incorporated into the Standard Model, which describes all the known particles (there are currently 31, including the Higgs boson) and three of the four known fundamental forces: the electromagnetic force, the strong nuclear force and the weak nuclear force, but not gravity. As well as allowing even more precise measurements of the particles that make up all the matter we see, scientists think the upgraded LHC can help resolve several anomalies in the Standard Model that have recently been reported.One of the most puzzling is a discrepancy in the decay of the B-meson, a transient particle composed of two types of quarks — the subatomic particles that make up protons and neutrons.According to theory, B-mesons should decay into electrons and muons — a related class of subatomic particles — with equal rarity. But experiments show B-mesons decay into electrons about 15 percent more often than they decay into muons, said particle physicist Chris Parkes, who leads the Large Hadron Collider Beauty (LHCb) experiment.LHCb is named for the “beauty” quark that features prominently in the experiment’s study of the differences between matter and antimatter (quarks can also be classified as “truth,” “up,” “down,” “charm” or “strange”, depending on their characteristics).Equal amounts of matter and antimatter should have annihilated each other in the first moments of the Big Bang, but that obviously didn’t happen: instead, matter predominates, and the LHCb experiment aims to find out why.The reported anomaly in the decay of B-mesons is related to that question, Parkes said, and the new run of the LHC could provide insights into why the anomalous decay is happening. “There are a lot of different measurements and, intriguingly, quite a number of them are pointing in the same sort of direction,” he said. “But there is not a ‘smoking gun’ — instead it is an intriguing picture that has been seen over the last few years.”Another other notable anomaly is in the mass of the W-boson, a subatomic particle involved in the action of the weak nuclear force that governs some types of radioactivity. The Standard Model predicts W-bosons have a mass of around 80,357 million electron volts, and that figure has been verified in several particle accelerator experiments.But a series of precise experiments at the massive Tevatron particle accelerator at Fermilab near Chicago suggest instead that the W-boson weighs a little more than it should — and that it might just point to “new physics” beyond the Standard Model.Particle physicist Ashutosh Kotwal, a professor at Duke University in Durham, North Carolina, who led the research at Fermilab that reported the discrepancy earlier this year, thinks it might be caused by a refinement of the Standard Model called “supersymmetry,” for which there’s been no firm evidence before now.Kotwal is also a researcher at the LHC, and he hopes its upgraded run could verify that supersymmetry is more than just an idea. “It is possible that the W-boson is sensing the existence of supersymmetric particles,” he said.And if supersymmetry does turn out to be a principle of the universe, it could explain several other mysteries — such as the nature of the ghostly “dark matter” particles that many physicists think make up around three-quarters of all the matter in the universe.Although the gravity from dark matter particles explains the structure of galaxies, the particles themselves have never been seen and physicists can’t yet explain what they might be.“If we look for indications of this particle directly at the LHC, that would be a manifestation of potential supersymmetry and it would be a manifestation of dark matter at the same time,” Kotwal said. “That’s the sort of thing I am pushing for.”
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Cosmology & The Universe
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Pennsylvania State University has an announcement. "Six massive galaxies discovered in the early universe are upending what scientists previously understood about the origins of galaxies in the universe." "These objects are way more massiveâ than anyone expected," said Joel Leja, assistant professor of astronomy and astrophysics at Penn State, who modeled light from these galaxies. "We expected only to find tiny, young, baby galaxies at this point in time, but we've discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe."
Using the first dataset released from NASA's James Webb Space Telescope, the international team of scientists discovered objects as mature as the Milky Way when the universe was only 3% of its current age, about 500-700 million years after the Big Bang.... In a paper published February 22 in Nature, the researchers show evidence that the six galaxies are far more massive than anyone expected and call into question what scientists previously understood about galaxy formation at the very beginning of the universe. "The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science," said Leja. "We've been informally calling these objects 'universe breakers' — and they have been living up to their name so far."
Leja explained that the galaxies the team discovered are so massive that they are in tension with 99% of models for cosmology. Accounting for such a high amount of mass would require either altering the models for cosmology or revising the scientific understanding of galaxy formation in the early universe — that galaxies started as small clouds of stars and dust that gradually grew larger over time. Either scenario requires a fundamental shift in our understanding of how the universe came to be, he added. "We looked into the very early universe for the first time and had no idea what we were going to find," Leja said. "It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question."
"My first thought was we had made a mistake and we would just find it and move on with our lives," Leja says in the statement. "But we have yet to find that mistake, despite a lot of trying."
"While the data indicates they are likely galaxies, I think there is a real possibility that a few of these objects turn out to be obscured supermassive black holes. Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought. Even if we cut the sample in half, this is still an astounding change."
Phys.org got a more detailed explantion from one of the paper's co-authors: It took our home galaxy the entire life of the universe for all its stars to assemble. For this young galaxy to achieve the same growth in just 700 million years, it would have had to grow around 20 times faster than the Milky Way, said Labbe, a researcher at Australia's Swinburne University of Technology. For there to be such massive galaxies so soon after the Big Bang goes against the current cosmological model which represents science's best understanding of how the universe works. According to theory, galaxies grow slowly from very small beginnings at early times," Labbe said, adding that such galaxies were expected to be between 10 to 100 times smaller. But the size of these galaxies "really go off a cliff," he said....
The newly discovered galaxies could indicate that things sped up far faster in the early universe than previously thought, allowing stars to form "much more efficiently," said David Elbaz, an astrophysicist at the French Atomic Energy Commission not involved in the research. is could be linked to recent signs that the universe itself is expanding faster than we once believed, he added.
This subject sparks fierce debate among cosmologists, making this latest discovery "all the more exciting, because it is one more indication that the model is cracking," Elbaz said.
Using the first dataset released from NASA's James Webb Space Telescope, the international team of scientists discovered objects as mature as the Milky Way when the universe was only 3% of its current age, about 500-700 million years after the Big Bang.... In a paper published February 22 in Nature, the researchers show evidence that the six galaxies are far more massive than anyone expected and call into question what scientists previously understood about galaxy formation at the very beginning of the universe. "The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science," said Leja. "We've been informally calling these objects 'universe breakers' — and they have been living up to their name so far."
Leja explained that the galaxies the team discovered are so massive that they are in tension with 99% of models for cosmology. Accounting for such a high amount of mass would require either altering the models for cosmology or revising the scientific understanding of galaxy formation in the early universe — that galaxies started as small clouds of stars and dust that gradually grew larger over time. Either scenario requires a fundamental shift in our understanding of how the universe came to be, he added. "We looked into the very early universe for the first time and had no idea what we were going to find," Leja said. "It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question."
"My first thought was we had made a mistake and we would just find it and move on with our lives," Leja says in the statement. "But we have yet to find that mistake, despite a lot of trying."
"While the data indicates they are likely galaxies, I think there is a real possibility that a few of these objects turn out to be obscured supermassive black holes. Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought. Even if we cut the sample in half, this is still an astounding change."
Phys.org got a more detailed explantion from one of the paper's co-authors: It took our home galaxy the entire life of the universe for all its stars to assemble. For this young galaxy to achieve the same growth in just 700 million years, it would have had to grow around 20 times faster than the Milky Way, said Labbe, a researcher at Australia's Swinburne University of Technology. For there to be such massive galaxies so soon after the Big Bang goes against the current cosmological model which represents science's best understanding of how the universe works. According to theory, galaxies grow slowly from very small beginnings at early times," Labbe said, adding that such galaxies were expected to be between 10 to 100 times smaller. But the size of these galaxies "really go off a cliff," he said....
The newly discovered galaxies could indicate that things sped up far faster in the early universe than previously thought, allowing stars to form "much more efficiently," said David Elbaz, an astrophysicist at the French Atomic Energy Commission not involved in the research. is could be linked to recent signs that the universe itself is expanding faster than we once believed, he added.
This subject sparks fierce debate among cosmologists, making this latest discovery "all the more exciting, because it is one more indication that the model is cracking," Elbaz said.
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Cosmology & The Universe
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Heatwaves on Earth may be uncomfortable and even dangerous for some, but our planet has nothing on the blisteringly hot world of WASP-76 b.
Astronomers have taken a deeper look at the exoplanet on which temperatures soar to around 4,350 degrees Fahrenheit (2,400 degrees Celsius), hot enough to vaporize iron. In the process, the team identified 11 chemical elements in the atmosphere of the planet and measured how abundant they are.
"Truly rare are the times when an exoplanet hundreds of light years away can teach us something that would otherwise likely be impossible to know about our own solar system," team leader and Université de Montréal Trottier Institute for Research on Exoplanets Ph.D. Stefan Pelletier said in a statement. "This is the case with this study."
Located around 634 light-years away in the Pisces constellation, the strange planet of WASP-76 b gets its incredible temperatures from its proximity to its parent star. Classified as an "ultra-hot Jupiter," which is a massive planet that exists incredibly close to its star, the exoplanet is a twelfth of the distance from its star, WASP-76, than Mercury is to the sun.
This gives WASP-76 b, which takes 1.8 Earth days to orbit its star, some other extraordinary properties. Though the planet has just around 85% of the mass of Jupiter, it is almost twice the width of the solar system gas giant and is around six times its volume. That is the result of intense radiation from its star "puffing out" the planet.
WASP-76 b has been the subject of intense study since it was found as part of the Wide Angle Search for Planets (WASP) program in 2013. This has led to the classification of several elements in its atmosphere. Most strikingly was the discovery in 2020 that iron vaporized on the side of the tidal-locked planet that permanently faces its star blows to the relatively cooler "night side" that perpetually faces space and condenses, falling as iron rain.
Spurred on by these previous investigations of WASP-76 b, Pelletier was inspired to obtain new observations of WASP-76 b with the MAROON-X high-resolution optical spectrograph on the Gemini North 8-meter Telescope in Hawaii, part of the International Gemini Observatory. This allowed the team to study the composition of the ultra hot Jupiter in unprecedented detail.
Because of the incredible temperatures of WASP-76 b, elements that would usually form rocks on terrestrial planets like Earth, such as magnesium and iron, are instead vaporized and lurk as gasses in the planet's upper atmosphere.
That means studying this world can give astronomers an unparalleled insight into the presence and abundance of rock-forming elements in the atmosphere of giant planets. This isn't possible for colder giant planets like Jupiter as these elements dwell lower in the atmosphere, making them impossible to detect.
What Pelletier and colleagues discovered during their investigation of WASP-76 b was that the abundance of elements like manganese, chromium, magnesium, vanadium, barium, and calcium match closely, not only the abundances of these elements in its own star but also the quantities found in the sun.
The elementary abundances seen aren't arbitrary; they are the result of the processing of hydrogen and helium by successive generations of stars over billions of years. A star creates heavier elements until it exhausts its fuel for nuclear fusion, dying in a supernova explosion. This blast releases those elements into the cosmos, and they become the building blocks of the next stars, with the remaining material surrounding these infant stars as proto-planetary disks, which, as the name suggests, can spawn planets. This means stars of similar ages have similar compositions with the same abundances of elements heavier than hydrogen and helium, which astronomers call "metals."
Because terrestrial planets such as ours form by more complex processes, however, they have different abundances of heavy elements than their stars. The fact that this new study shows WASP-76 b has a similar composition to its star means its composition is also similar to the protoplanetary disk of material that collapsed to birth it. And this could be true of all giant planets.
Not everything discovered about the composition of WASP-76 b was so expected, however. The team discovered that certain elements in the atmosphere of Wasp-76 b appeared to be "depleted."
"These elements that appear to be missing in WASP-76 b's atmosphere are precisely those that require higher temperatures to vaporize, like titanium and aluminum, " Pelletier said. "Meanwhile, the ones that matched our predictions, like manganese, vanadium, or calcium, all vaporize at slightly lower temperatures."
The team interpreted this depletion as indicative of the composition of the upper atmosphere of gas giant planets being sensitive to temperature. Depending on the temperature at which an element condenses, it will either be present as a gas in the upper atmosphere or missing because it has condensed to liquid and sank to lower layers. From lower in the atmosphere, the element can't absorb light making its characteristic "fingerprint" missing in observations.
"If confirmed, this finding would mean that two giant exoplanets that have slightly different temperatures from one another could have very different atmospheres," Pelletier explained. "Kind of like two pots of water, one at -1°C that is frozen, and one that is at +1°C that is liquid. For example, calcium is observed on WASP-76 b, but it may not be on a slightly colder planet."
The team made another important discovery about the atmosphere of WASP-76 b; it contains a chemical compound called vanadium oxide. The first time this compound has been spotted in the atmosphere of a planet outside the solar system. The discovery will be of great interest to astronomers because vanadium oxide can have a big impact on hot giant planets.
"This molecule plays a similar role to ozone in Earth's atmosphere: it is extremely efficient at heating up the upper atmosphere," Pelletier explained. "This causes the temperatures to increase as a function of altitude, instead of decreasing as is typically seen on colder planets."
The team also found a higher abundance of nickel than expected around WASP-76 b, which could imply that at some point in its history, the gas giant planet swallowed a smaller terrestrial world similar to Mercury that was rich with the element.
The astronomers behind these revelations will continue to study this exoplanet and other similar worlds, attempting to discover how temperatures affect the composition of their atmospheres. As they do this, the team said it hopes that some of the things they learn can be applied to giant planets closer to home.
The research is described in a paper published on Wednesday (June 14) in the journal Nature.
Originally published on Space.com.
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Robert Lea is a science journalist in the U.K. who specializes in science, space, physics, astronomy, astrophysics, cosmology, quantum mechanics and technology. Rob's articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University
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Cosmology & The Universe
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September 22, 2022 09:29 AM NASA released new images taken from its James Webb Space Telescope, capturing details of Neptune’s dust bands, which have never been seen in infrared before, and its surrounding moons. The new photographs, which were taken in July and released on Wednesday, show Neptune’s thin rings, its faint dust bands, and seven of the planet’s known moons. This composite image provided by NASA on Sept. 21, 2022, shows three side-by-side images of Neptune. From left, a photo of Neptune taken by Voyager 2 in 1989, Hubble in 2021, and Webb in 2022. In visible light, Neptune appears blue due to small amounts of methane gas in its atmosphere. Webb’s Near-Infrared Camera instead observed Neptune at near-infrared wavelengths, where Neptune resembles a pearl with thin, concentric oval rings. (NASA, ESA, CSA, STScI via AP) SEE IT: NASA RELEASES NEW IMAGES OF JUPITER The images are the first that have been captured since NASA’s Voyager 2 conducted a flyby in 1989, meaning it has been more than three decades since scientists have viewed Neptune’s rings with such clarity, according to the Associated Press. No other spacecraft has visited the solar system’s outermost planet. NASA launched its Webb Telescope less than a year ago, investing $10 billion into exploring deep into the universe and capturing never-before-seen images. Astronomers hope it will help them look back into the beginning of time when stars and galaxies started to form. CLICK HERE TO READ MORE FROM THE WASHINGTON EXAMINER The images of Neptune come a month after NASA released new Webb images of Jupiter that show the gas giant in detail, revealing its rings and auroras occurring at its north and south poles.
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Cosmology & The Universe
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Astronomers explore a recently discovered luminous quasar
Using various space telescopes, an international team of astronomers have observed a recently detected luminous quasar known as SMSS J114447.77-430859.3, or J1144 for short. Results of the observational campaign, available in the July 2023 edition of Monthly Notices of the Royal Astronomical Society, shed more light on the properties of this source.
Quasars, or quasi-stellar objects (QSOs) are active galactic nuclei (AGN) of very high luminosity, emitting electromagnetic radiation observable in radio, infrared, visible, ultraviolet and X-ray wavelengths. They are among the brightest and most distant objects in the known universe, and serve as fundamental tools for numerous studies in astrophysics as well as cosmology. For instance, quasars have been used to investigate the large-scale structure of the universe and the era of reionization. They also improved our understanding of the dynamics of supermassive black holes and the intergalactic medium.
J1144 was detected in June 2022 at a redshift of 0.83. It has a bolometric luminosity of about 470 quattuordecillion erg/s, which makes it the most luminous quasar over the last 9 billion years of cosmic history. It is also the optically brightest (unbeamed) quasar at a redshift greater than 0.4.
It is estimated that the mass of the black hole in J1144 is approximately 2.6 billion solar masses. This value, together with the high bolometric luminosity, yields an Eddington ratio at a level of 1.4 for this quasar.
A group of astronomers led by Elias Kammoun of the University of Toulouse, France, has conducted X-ray observations of this quasar using Spektr-RG, Swift, NuSTAR and XMM-Newton space telescopes. These four space observatories allowed them to gain more insights into the properties of J1144.
The observational campaign found that J1144 exhibits an X-ray variability by a factor of about 10 within a year. Moreover, the results indicate also a shorter timescale variability of the order of approximately 2.7 within 40 days. According to the authors of the study, the large X-ray variability is due to intrinsic changes in the X-ray luminosity of the source accompanied with changes in the absorption in the line of sight.
The observations indicate that J1144 seems to accrete at a rate larger than 40% of the Eddington limit. However, the astronomers noted that If the black hole spin is relatively low, the accretion rate can even exceed the Eddington limit.
The researchers underlined that the X-ray and optical properties of J1144 are different from many high-Eddington sources. They suppose that this source may be a standard radio-quiet quasar rather than a high-Eddington quasi-stellar object.
The authors of the paper added that deeper X-ray and ultraviolet/optical observations of J1144 are needed to draw final conclusions about the nature of this source and its variability.
More information: E S Kammoun et al, The first X-ray look at SMSS J114447.77-430859.3: the most luminous quasar in the last 9 Gyr, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad952
Journal information: Monthly Notices of the Royal Astronomical Society
© 2023 Science X Network
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Cosmology & The Universe
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Let’s see what’s out there
NASA’s James Webb Space Telescope is the world’s largest and most complex in history and is expected to send images to Earth this week.
The James Webb Space Telescope’s revolutionary technology will study every phase of cosmic history — from within our solar system to the most distant observable galaxies of the early universe.
Webb’s infrared telescope will explore a wide range of science questions to help us understand the origins of the universe. Science targets: First light and reionization
Earliest galaxies in the universe
How galaxies evolve
Birth of stars and planets
Exoplanets Instruments: Near-infrared camera
Near-infrared spectrograph
Mid-infrared instrument
Near-infrared imager and slitless spectrograph with fine guidance sensor Webb is an international collaboration between NASA and its partners, the European Space Agency and the Canadian Space Agency.
Thousands of engineers and hundreds of scientists worked to make Webb a reality, along with more than 300 universities, organizations and companies from 29 U.S. states and 14 countries. Development began in 1996 for a launch initially planned for 2007 with a $500 million budget. There were many delays and cost overruns, including a major redesign in 2005, a ripped sunshield during a practice deployment, recommendations from an independent review board, a threat by the U.S. Congress to cancel the project, the COVID-19 pandemic and problems with the telescope.
Construction was completed in late 2016, followed by years of extensive testing before launch. The total project cost is expected to be about $9.7 billion.
Some Webb developments have had spinoff benefits. One example assists surgeons performing LASIK eye surgery: Engineers developed a technique for precisely and rapidly measuring the mirrors to guide their grinding and polishing.
This technology has since been adapted to creating high-definition maps of patients’ eyes for improved surgical precision.
The observatory has a temperature range from minus-390 degrees Fahrenheit on the inner layer to 260 degrees on the outer layer. It will operate at about minus-370 degrees. Webb will peer back in time to when the universe was young — more than 13.5 billion years ago, a few hundred million years after the big bang theory — to search for the first galaxies in the universe.
Webb is so sensitive that it could theoretically detect the heat signature of a bumblebee at the distance of the moon.
Why Infrared?
Webb will study infrared light from celestial objects with much greater clarity and sensitivity than ever before.
Unlike the short, tight wavelengths of visible light, longer wavelengths of infrared light slip past dust more easily.
Therefore, the universe of star and planet formation hidden behind clouds of dust comes into clear view for Webb’s infrared instruments. Historyoftelescope.com timeline – significant events in telescope history
1608 — German-Dutch spectacle-maker Hans Lippershey applies his patent on what is today known as telescope. He managed to beat two other Dutch scientists (Jacob Metius and Zacharias Janssen) who also tried to register their own inventions.
1611 — The name “telescope” is created by Greek mathematician Giovanni Demisiani, during his visit at Italian science academy “Accademia dei Lincei” that hosted one of the Galileo Galilei’s telescopes. This word was coined from the words “tele” (far) and “skopein” (to look, or to see).
The Oldest Observatory in the Americas is found in Bogotá, Colombia (1803).
1970 — First telescope launched into space onboard probe Uhuru. This was also first gamma-ray telescope ever to be used.
Since 1970 there have been more than 90 Space Telescopes placed into Orbit by NASA and ESA. An average of 2 per year. Some Are Longer Lived Than Others. 61 Are No Longer Active, 26 Are Still Active.
1975 — BTA-6 is the first major telescope to use an altazimuth mount, which is mechanically simpler but requires computer control for accurate pointing.
1990 — Hubble telescope launched into Earth’s orbit. It quickly became one of the most famous and most important telescopes ever to be built.
2003 — The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility, is an infrared space observatory launched in 2003. It is the fourth and final of the NASA Great Observatories program.
2008 — Max Tegmark and Matias Zaldarriaga created the Fast Fourier Transform Telescope.
2009 – Kepler telescope launched in space, with goal of locating planets that are orbiting our neighboring stars. It has 2.4m diameter mirror.
2011 — NASA announces plans to launch in 2018 the most ambitious space telescope of all time. James Webb Space Telescope will operate in deep space and have staggering 6.5m diameter mirror.
2022 — The James Webb telescope is launched by NASA.
In the July skies
July 13 – Full Buck Moon Super Supermoon at 2:38 p.m.While this will be the “biggest” full Moon of 2022, the variation of the Moon’s distance will not be apparent to observers. However the Moon’s closeness to Earth does dramatically affect the tides, which may cause severe coastal flooding.At 3 a.m. on this day the Moon will arrive at perigee. This means that the Moon will get the closest it will come to Earth in all of 2022, 221,994 miles away. Its gravitational pull creates extreme high and low ocean tides. Such a tide is known as a perigean spring tide.
July 29 – Two Meteor Showers PeakSeveral long-lasting meteor showers appear to dart from the southern part of the sky from mid-July through August. The Moon being in its “new” phase combined with two meteor shower reaching their peak makes for a great opportunity to catch a shooting star.The South Delta Aquarid shower, which emanates from the constellation Aquarius, will reach its maximum on this morning. (Start looking after midnight.) Also peaking around this time is the Alpha Capricornid shower, which emanates from the constellation Capricornus. There will be a high proportion of bright meteors. Look to the southern sky.
Sources: NASA, History of Telescope, Space.com, The Associated Press Top image is a artist conception NASA GSFC/CIL/Adriana Manrique Gutierrez
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Cosmology & The Universe
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Ahead of the biggest premiere the world of astronomy has ever seen, NASA has published the cosmic A-list that will be appearing through the lens of its colossal new space telescope.And it's not just stars. There are galaxies, a planet too, and what promises to be the deepest view back in time that humanity has ever been able to achieve.
On Tuesday, the first images from the $10bn James Webb Space Telescope (JWST) will be shared with the world.Only a handful of the thousands of scientists and engineers who are working on the project have seen them. But the words "spectacular," and "beautiful," are being whispered among those who have.In a teaser ahead of the main release, NASA, the European and Canadian Space Agencies, which collaborated on the JWST, published a list of the five places in the universe that have been imaged by the telescope first. The locations are not exactly household names, but they have been carefully picked to showcase the capabilities of the new infrared telescope and its enormous 6.5 metre gold-plated mirror.
First is the Carina Nebula, a 50 light-year-wide cloud of dust and stars 1000 light years from earth. It's one of the most beautiful objects in our galaxy. But it's also important for understanding how we came to exist. The colossal cloud of dust and gas is one of the most active star-forming regions discovered so far. It's likely our solar system formed in a place just like it. More from Science & Tech Twitter to sue Elon Musk after he pulls plug on $44bn takeover deal NASA criticises Russia for using space station to stage propaganda photographs Global wheat production can be doubled to feed millions and save land, say scientists Astrophysicist Prof Martin Barstow at the University of Leicester said: "Infrared allows you to penetrate through that dust and gas."It will give us a completely new perspective."Star-forming regions, are more than just scientifically interesting, according to Dr Jeffery Kargel of the Planetary Science Institute in Tucson, Arizona."They are not just beautiful, but they are philosophically mind-blowing and even spiritually stirring when pondering the processes of creation and destruction, and the near-certain origins of life in many, many planets around many stars in the nebula."Arguably the most mind-blowing target is one little-known outside the field of astronomy. Image: SMACS 0723. Pic: Space Telescope Science Institute A region called SMACS 0723, where massive clusters of distant galaxies act to bend light due to their huge gravity. This "gravitational lens" brings the very earliest light in the universe into view.We haven't been able to see it before because the light is in the infrared spectrum - beyond the optics of the Hubble Space Telescope and invisible through our dusty atmosphere on Earth.The prize, said Prof Barstow is "first light": the potential JWST has to capture the very earliest light in the universe which came into being about 400 million years after the Big Bang."Webb is the only tool we have to do this," said Prof Barstow.Will JWST be able to make out any objects in the infrared gloom? We'll have to wait to find out.An entirely new view of a group of colliding galaxies called the Stephan's Quintet will feature, as well as the "cosmic smoke ring" left by an exploded star called the Southern Ring Nebula. Image: Stephan's Quintet. Pic: NASA Image: The 'cosmic smoke ring' left by an exploded star called the Southern Ring Nebula. Pic: NASA The final target is miniscule compared to the others. A planet called WASP-96-b, more than 1000 light years from Earth, orbiting a star very like our own Sun.It is hoped that JWST's measurements of this planet will prove its capabilities as a tool for seeking life elsewhere in the universe."This will not be a visual spectacle, but it will be a scientific treasure," said Dr Kargel.JWST will be able to study the chemical make-up of the planet's atmosphere in unprecedented detail by imaging it as it passes in front of its star.Don't get too excited - WASP-96-b is a Jupiter-like planet very close to its star so almost certainly scorching and lifeless.These obscure objects in the night sky may leave quite a lot of people cold. But excitement among astronomers, cosmologists and planetary scientists ahead of Tuesday's big reveal is palpable."Strap your brain in, batten down the hatches, and wait for your mind to be blown. It will be a Category 5," said Dr Kargel.
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Cosmology & The Universe
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Why is the sky dark at night? The 200-year history of a question that transformed our understanding of the universe
As dawn rose over the German city of Bremen on May 7, 1823, Heinrich Olbers put the finishing touches to an article that left his name in history. After the deaths of his wife and daughter, Dr. Olbers had recently given up his work as an opthalmologist to devote himself to his nocturnal passions: the stars, the moon, meteorites and comets.
Like many of his peers, Olbers trained himself in astronomy. He gained a solid reputation in the academic world and spent long nights observing the sky from the observatory on the second floor of his house.
On that morning, Olbers had come to a strange conclusion: based on all that was known about the universe at that time, the night sky should not have been dark. In fact, the entire heavens should have been glowing as brightly as the sun.
Olbers was not the first to note this paradox. But his name is the one we attach to it today. The enigma of the night sky's darkness has echoed down the centuries from Olbers and the poet Edgar Allan Poe to 20th-century astronomers and space probes today.
Finite light in an infinite universe
Like many of his contemporaries, Olbers followed Isaac Newton and René Descartes in believing the universe was infinite.
If the universe were finite and static, the force of gravity should draw all the stars together at a central point. But if the universe stretched on forever, gravitational forces would on average be balanced in all directions.
But Olbers realized this model of the cosmos was inconsistent with observations. In a limitless universe filled with an infinite number of stars, wherever we look at night our gaze should land on the surface of a star, in much the same way as every line of sight in a forest ends at a tree.
This is the problem Olbers raised in his paper of May 7, 1823: the cosmological model of the time suggested every point in the sky should be as bright as the surface of the sun. There should be no night.
Olbers proposed a solution: the light from more distant stars was absorbed by dust or other material floating in space. The English astronomer John Herschel later pointed out this couldn't be right, because anything absorbing that much light would eventually heat up enough to glow.
When Olbers died on March 2, 1840, at the age of 81, the riddle we know today as Olber's paradox was unsolved.
A poet's intuition
Eight years later, on the other side of the Atlantic Ocean, poet and writer Edgar Allan Poe thought he had found an answer. On February 3, 1848, he gave a public lecture about his ideas to 60 people at the New York Society Library.
Veering between metaphysics and science, Poe argued the cosmos had emerged from a single state of matter ("Oneness") that fragmented and dispersed under the action of a repulsive force.
This meant the universe was a finite sphere of matter. If the finite universe is populated by a sufficiently small number of stars, then we won't see one in every direction we look. The night can be dark again.
Even if we assume the universe is infinite, if it began at some point in the past then the time taken by light to reach us would limit the size of the amount of the universe we can see. This travel time would create a horizon beyond which distant stars would remain inaccessible.
Poe's audience at the New York Society Library did not give him the rapturous reception he had hoped for. Later the same year, he published his theories in the prose poem Eureka, which was little circulated.
The following year, on October 7, 1849, Poe died at the age of 40. It would be more than a century before scientists confirmed his intuitions about the enigma of the dark night sky.
Two and a half facts
In the first half of the 20th century many new theories of the cosmos were developed, spurred on by Einstein's theory of general relativity, which explained gravity, space and time in new ways. In the second half of the century, these cosmological theories began to be tested with observations.
In 1963, British astronomer Peter Scheuer argued that cosmology was based on only "two and a half facts":
- fact 1: the night sky is dark, which had been known for some time
- fact 2: galaxies are moving away from each other, as shown by Hubble's observations published in 1929
- fact 2.5: the content of the universe is probably evolving as cosmic time unfolds.
Strong controversies on the interpretation of facts 2 and 2.5 agitated the scientific community in the 1950s and 1960s. Was the universe essentially stationary, or had it begun in an enormous explosion—a Big Bang? Supporters of both sides conceded, however, they needed to explain the darkness of the night sky.
The lifetime of stars
British cosmologist Edward Harrison resolved the conflict in 1964. He showed that the main factor determining the brightness of the night sky is actually the finite age of the stars.
The number of stars in the observable universe is extremely large, but it is finite. This limited number, each burning for a limited time, spread over a gigantic volume, lets darkness manifest itself between the stars.
Harrison later realized this solution had already been proposed not only by Edgar Allan Poe, but by British physicist Lord Kelvin in 1901.
Observations in the 1980s confirmed the resolution proposed by Poe, Kelvin and Harrison. Olber's paradox had finally been put to rest.
Fossil light
Or perhaps not quite. Viewed from a different angle, there is another resolution to the paradox: the night sky is not actually so dark after all.
After the discovery of the expansion of the universe in the late 1920s, scientists realized the universe could have started off extremely compact, dense and hot. This is the "hot Big Bang" model we have today.
One core prediction of this model is the existence of "fossil light" released in the cosmic dawn. This fossil light should be observable today—but not with the naked eye, as the expanding universe would have shifted it to longer wavelengths.
We now know the cosmos is also illuminated by a second, much fainter background light, produced by galaxies as they form and evolve. This light is referred to as the cosmic ultraviolet, optical and infrared background.
New answers, new questions
In 2023, Olber's paradox has evolved into a rich field of research. In our own work, we carry out ever-more precise measurements of the brightness of the night sky, and simulate the stars of the cosmos with supercomputers. We can now determine the number of stars in the sky with great accuracy.
Nevertheless, puzzles remain. Last year the New Horizons space probe, out beyond the orbit of Pluto and away from the dust of the inner Solar System, found the sky is twice as bright as we expected it to be.
And so the question of the darkness of the sky lives on, crossing ages and cultures.
Provided by The Conversation
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Cosmology & The Universe
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Colliding neutron stars provide a new way to measure the expansion of the universe
In recent years, astronomy has seen itself in a bit of crisis: Although we know that the universe expands, and although we know approximately how fast, the two primary ways to measure this expansion do not agree. Now astrophysicists from the Niels Bohr Institute suggest a novel method which may help resolve this tension.
We've known this ever since Edwin Hubble and other astronomers, some 100 years ago, measured the velocities of a number of surrounding galaxies. The galaxies in the universe are "carried" away from each other by this expansion, and therefore recedes from each other.
The greater the distance between two galaxies, the faster they move apart, and the precise rate of this movement is one of the most fundamental quantities in modern cosmology. The number that describes the expansion goes by the name "the Hubble constant," appearing in multitude of different equations and models of the universe and its constituents.
Hubble trouble
To understand the universe we must therefore know the Hubble constant as precisely as possible. Several methods exist to measure it; methods that are mutually independent but luckily give almost the same result.
That is, almost. The intuitively easiest method to understand is, in principle, the same that Edwin Hubble and his colleagues used a century ago: Locate a bunch of galaxies, and measure their distances and speeds. In practice this is done by looking for galaxies with exploding stars, so-called supernovae. This method is complemented by another method that analyzes irregularities in the so-called cosmic background radiation; an ancient form of light dating back to shortly after the Big Bang.
The two methods—the supernova method and the background radiation method—always gave slightly different results. But any measurement comes with uncertainties, and a few years back the uncertainties were substantial enough that we could blame those for the disparity.
Nevertheless, as measurement techniques have improved, uncertainties have diminished, and we've now reached a point where we can state with a high degree of confidence that both cannot be correct.
The root of this "Hubble trouble"—whether it is unknown effects systematically biasing one of the results, or if it hints at new physics yet to be discovered—is currently one of astronomy's hottest topics.
Crashing neutron stars may help with the answer
One of the greatest challenges lies in accurately determining the distances to galaxies. But in a recent study published in Astronomy & Astrophysics, Albert Sneppen who is a Ph.D. student in astrophysics at the Cosmic Dawn Center at the Niels Bohr Institute in Copenhagen, proposed a novel method for measuring distances, thereby helping to settle the ongoing dispute.
"When two ultra-compact neutron stars—which in themselves are the remnants of supernovae—orbit each other and ultimately merge, they go off in a new explosion; a so-called kilonova," Albert Sneppen explains. "We recently demonstrated how this explosion is remarkedly symmetric, and it turns out that this symmetry not only is beautiful, but also incredibly useful."
In a third study that has just been published in The Astrophysical Journal, the prolific Ph.D. student shows that kilonovae, despite their complexity, can be described by a single temperature. And it turns out that the symmetry and the simplicity of the kilonovae enable the astronomers to deduce exactly how much light they emit.
Comparing this luminosity with how much light reaches Earth, the researchers can calculate how far away the kilonova is. They have thereby obtained a novel, independent method to calculate the distance to galaxies containing kilonovae.
Darach Watson is an associate professor at the Cosmic Dawn Center and a co-author of the study. He explains: "Supernovae, which until now have been used to measure the distances of galaxies, don't always emit the same amount of light. Moreover, they first require us to calibrate the distance using another type of stars, the so-called Cepheids, which in turn also must be calibrated. With kilonovae we can circumvent these complications that introduce uncertainties in the measurements."
Confirms one of the two methods
To demonstrate its potential, the astrophysicists applied the method to a kilonova discovered in 2017. The result is a Hubble constant closer to the background radiation method, but whether the kilonova method can resolve the Hubble trouble, the researchers do not yet dare to state.
"We only have this one case study so far, and need many more examples before we can establish a robust result," Albert Sneppen cautions. "But our method at least bypasses some known sources of uncertainty, and is a very 'clean' system to study. It requires no calibration, no correction factor."
More information: Albert Sneppen et al, Measuring the Hubble constant with kilonovae using the expanding photosphere method, Astronomy & Astrophysics (2023). DOI: 10.1051/0004-6361/202346306
Albert Sneppen, On the Blackbody Spectrum of Kilonovae, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/acf200
Provided by Niels Bohr Institute
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Cosmology & The Universe
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Our view of the universe just expanded: The first image from NASA’s new space telescope unveiled Monday is brimming with galaxies and offers the deepest look of the cosmos ever captured.The first image from the $10 billion James Webb Space Telescope is the farthest humanity has ever seen in both time and distance, closer to the dawn of time and the edge of the universe. That image will be followed Tuesday by the release of four more galactic beauty shots from the telescope’s initial outward gazes.The “deep field” image released at during a brief White House event is filled with lots of stars, with massive galaxies in the foreground and faint and extremely distant galaxies peeking through here and there. Part of the image is light from not too long after the Big Bang, which was 13.8 billion years ago.President Joe Biden marveled at the image that he said showed “the oldest documented light in the history of the universe from over 13 billion -- let me say that again -- 13 billion years ago. It’s hard to fathom.”The busy image with hundreds of specks, streaks, spirals and swirls of white, yellow, orange and red is only “one little speck of the universe,” NASA Administrator Bill Nelson said. “What we saw today is the early universe,” Harvard astronomer Dimitar Sasselov said in a phone interview after the reveal.Sasselov said he and his colleague Charles Alcock first thought “we’ve seen this before.” Then they looked closer at the image and pronounced the result not only beautiful but “worth all that waiting” for the much-delayed project.And even more is coming Tuesday. The pictures on tap include a view of a giant gaseous planet outside our solar system, two images of a nebula where stars are born and die in spectacular beauty and an update of a classic image of five tightly clustered galaxies that dance around each other. The world’s biggest and most powerful space telescope rocketed away last December from French Guiana in South America. It reached its lookout point 1 million miles (1.6 million kilometers) from Earth in January. Then the lengthy process began to align the mirrors, get the infrared detectors cold enough to operate and calibrate the science instruments, all protected by a sunshade the size of a tennis court that keeps the telescope cool.The plan is to use the telescope to peer back so far that scientists will get a glimpse of the early days of the universe about 13.7 billion years ago and zoom in on closer cosmic objects, even our own solar system, with sharper focus. How far back past 13 billion years did that first image look? NASA didn’t provide any estimate Monday. Outside scientists said those calculations will take time, but they are fairly certain somewhere in the busy image is a galaxy older than humanity has ever seen, probably back to 500 million or 600 million years after the Big Bang.“It takes a little bit of time to dig out those galaxies,” University of California, Santa Cruz, astrophysicist Garth Illingworth said. “It’s the things you almost can’t see here, the tiniest little red dots.”“This is absolutely spectacular, absolutely amazing,” he added. “This is everything we’ve dreamed of in a telescope like this.”Webb is considered the successor to the highly successful, but aging Hubble Space Telescope. Hubble has stared as far back as 13.4 billion years. It found the light wave signature of an extremely bright galaxy in 2016. Astronomers measure how far back they look in light-years with one light-year being 5.8 trillion miles (9.3 trillion kilometers).“Webb can see backwards in time to just after the Big Bang by looking for galaxies that are so far away that the light has taken many billions of years to get from those galaxies to our telescopes,” said Jonathan Gardner, Webb’s deputy project scientist said during a June media briefing. The deepest view of the cosmos “is not a record that will stand for very long,” project scientist Klaus Pontoppidan said during the briefing, since scientists are expected to use the Webb telescope to go even deeper.At 21 feet (6.4 meters), Webb’s gold-plated, flower-shaped mirror is the biggest and most sensitive ever sent into space. It’s comprised of 18 segments, one of which was smacked by a bigger than anticipated micrometeoroid in May. Four previous micrometeoroid strikes to the mirror were smaller. Despite the impacts, the telescope has continued to exceed mission requirements, with barely any data loss, according to NASA.NASA is collaborating on Webb with the European and Canadian space agencies.“I’m now really excited as this dramatic progress augurs well for reaching the ultimate prize for many astronomers like myself: pinpointing “Cosmic Dawn” — the moment when the universe was first bathed in starlight,” Richard Ellis, professor of astrophysics at University College London, said by email.___AP Aerospace Writer Marcia Dunn contributed.___The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
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Cosmology & The Universe
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Between the smallest stars and the most massive planets, a strange class of celestial objects pervades the universe. Called brown dwarfs, or "failed stars," these liminal objects are more massive than gas giants such as Jupiter but less massive than the smallest stars.
They're also really common: Astronomers recently discovered that there could be as many as 100 billion of these faintly glowing bodies scattered throughout the Milky Way. With estimates of the Milky Way's stellar population ranging from 100 billion to 400 billion, that means brown dwarfs could be almost as common as stars themselves.
But why do brown dwarfs fail to become stars?
Why do brown dwarfs "fail"?
The short answer is that brown dwarfs don't have enough mass to trigger the steady nuclear fusion of hydrogen.
Both stars and brown dwarfs are born when massive clouds of gas and dust collapse. These "protostars" continue to gather material from these clouds until they reach masses at which the internal pressure and temperature are significant enough to trigger hydrogen burning, fusing hydrogen atoms to create helium.
"For what distinguishes a star and brown dwarf, it goes back to the fact that low mass stars (M dwarfs) have stable hydrogen fusion, and the smallest of these will have fusion for trillions of years — longer than the current age of the universe," Nolan Grieves, a postdoctoral researcher in the Department of Astronomy at the University of Geneva, told Live Science via email. "Whereas high mass brown dwarfs do not achieve stable fusion over the long term."
But that doesn't mean brown dwarfs don't burn hydrogen at all.
"Interestingly, some brown dwarfs will become hot enough to start hydrogen fusion, but they cannot balance nuclear burning in their core with photon losses at their surface," he said. "So their core temperature eventually falls below the hydrogen burning limit."
So, if brown dwarfs can't be considered stars, wouldn't it just be easier to classify them as very massive planets? That doesn't really work either.
Why aren't brown dwarfs considered planets?
Even though a brown dwarf can't achieve stable hydrogen fusion, that doesn't mean it is incapable of sustaining any form of nuclear fusion at its core.
The dividing line between brown dwarfs and gas giant planets is generally considered somewhere between 10 and 14 times the mass of the solar system's most massive planet, Jupiter. That means we shouldn't find a planet with more than around 13 times the mass of Jupiter.
This is because, at this mass, celestial bodies are capable of triggering the steady nuclear burning of deuterium, a "heavy" form of hydrogen. Rather than having a nucleus of just one proton as does "standard" hydrogen — the universe's lightest element — deuterium has a nucleus of one positively charged proton and a non-charged neutron. This is the reason brown dwarfs can have a faint glow.
"The major difference between brown dwarfs and planets is their mass and the occurrence of deuterium burning," Grieves said. "At larger masses, an object will have a high enough internal pressure and temperature to burn a majority of the deuterium that was initially present in the object."
The dividing line has been set so brown dwarfs are classified as objects that burned 50% or more of their initial deuterium. Yet that line is blurry, because other characteristics beyond mass — like the fraction of helium in a celestial body — could result in the burning of deuterium.
In the future, Grieves said, it might be possible for the difference between planets and brown dwarfs to be redefined: Brown dwarfs could be classed as celestial objects that are not stars but are created when a cloud of gas and dust collapses, whereas planets could be defined as overdense blobs that form in a disk of protoplanetary material around a collapsed star.
Until then, these fascinating celestial objects may have to exist with the suggestion of "failure."
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Robert Lea is a science journalist in the U.K. who specializes in science, space, physics, astronomy, astrophysics, cosmology, quantum mechanics and technology. Rob's articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University
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Cosmology & The Universe
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It's being described as the most detailed ever map of the influence of dark matter through cosmic history.
A telescope in Chile has traced the distribution of this mysterious stuff on a quarter of the sky and across almost 14 billion years of time.
The result is once again a spectacular confirmation of Einstein's ideas.
Although dark matter makes up about 85% of all mass in the Universe, it's extremely difficult to detect and defies a ready description.
But dark matter influences the large scale structure of everything we see - where all the galaxies are, where the voids in space are. It's the scaffolding on which the visible structure of the Universe is hung.
It neither emits nor absorbs light. The only way you can very obviously infer its presence is through its interplay with gravity.
Big rotating galaxies of stars would fly apart were it not for the inclusion of some unseen mass pulling on them and keeping them intact.
But dark matter will bend, or lens, background light, and this is how its whereabouts was mapped by the Atacama Cosmology Telescope (ACT).
The Chile facility observed the Cosmic Microwave Background, or CMB - a pervasive but faint glow of long-wavelength radiation that comes to us from the very edge of the observable Universe.
ACT mapped the subtle distortions in this ancient light that were introduced as it passed by all intervening matter.
You can liken it to the way light is bent as it passes through the bulges and bumps of in an old glass window pane.
If you know what you're looking at outside, you can use the distortions to say something about the glass.
In the same way, the CMB can be decoded to reveal all intervening structure on its journey to us.
There have been "gravitational lensing" detections similar to this in the past, most notably by the European Space Agency's Planck observatory a decade ago. But ACT surpasses all in terms of resolution and sensitivity.
Composition of the Universe
Successive experiments indicate the cosmic contents include:
roughly 5% normal matter - atoms, the stuff from which we are all made
about 27% dark matter - so far unseen directly and defying description
around 68% dark energy - the mysterious component accelerating cosmic expansion
The Universe is calculated to be 13.8 billion years old
In the image at the top of this page, the coloured areas are the portions of the sky studied by the telescope.
Orange regions show where there is more mass, or matter, along the line of sight; purple where there is less. Typical features are hundreds of millions of light-years across.
The grey/white areas show where contaminating light from dust in our Milky Way galaxy has obscured a deeper view.
The distribution of matter agrees very well with scientific predictions.
ACT observations indicate that the "lumpiness" of the Universe and the rate at which it has been expanding after 14 billion years of evolution are just what you'd expect from the standard model of cosmology, which has Einstein's theory of gravity (general relativity) at its foundation.
Recent measurements that used an alternative background light, one emitted from stars in galaxies rather than the CMB, had suggested the Universe lacked sufficient lumpiness.
"It's one of the 'cosmic tensions' we all talk about," said Prof Jo Dunkley from Princeton University, US. "But with this new result, we find exactly the right amount of lumpiness - no tension! So, if there is a tension, it is something that appears in the galaxy data - not in ours," she told BBC News.
Another tension concerns the rate at which the Universe is expanding - a number called the Hubble constant.
When Planck looked at temperature fluctuations across the CMB, it determined the rate to be about 67 kilometres per second per megaparsec (A megaparsec is 3.26 million light-years).
Or put another way - the expansion increases by 67km per second for every 3.26 million light-years we look further out into space.
A tension arises because measurements of the expansion in the nearby Universe, made using the recession from us of variable stars, clocks in at about 73km/s per megaparsec.
It's a difference that can't easily be explained.
ACT, employing its lensing technique to nail down the expansion rate, outputs a number similar to Planck's. "It's very close - about 68km/s per megaparsec," said Dr Mathew Madhavacheril from the the University of Pennsylvania.
ACT team-member Prof Blake Sherwin from Cambridge University, UK, added: "We and Planck and several other probes are coming in on the lower side. Obviously, you could have a scenario where both the measurements are right and there's some new physics that explains the discrepancy. But we're using independent techniques, and I think we're now starting to close the loophole where we could all be riding this new physics and one of the measurements has to be wrong."
Papers describing the new results have been submitted to The Astrophysical Journal and posted on the ACT website.
The telescope, which worked from 2007 to 2022 before being dismantled, was funded by the US National Science Foundation. The scientific collaboration has yet to finish analysing all its data.
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Cosmology & The Universe
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There is a galaxy spinning like a record in the early universe — far earlier than any others have been seen twirling around. Astronomers have spotted signs of rotation in the galaxy MACS1149-JD1, JD1 for short, which sits so far away that its light takes 13.3 billion years to reach Earth. “The galaxy we analyzed, JD1, is the most distant example of a rotational galaxy,” says astronomer Akio Inoue of Waseda University in Tokyo. Sign Up For the Latest from Science News Headlines and summaries of the latest Science News articles, delivered to your inbox “The origin of the rotational motion in galaxies is closely related to a question: how galaxies like the Milky Way formed,” Inoue says. “So, it is interesting to find the onset of rotation in the early universe.” JD1 was discovered in 2012. Due to its great distance from Earth, its light had been stretched, or redshifted, into longer wavelengths, thanks to the expansion of the universe. That redshifted light revealed that JD1 existed just 500 million years after the Big Bang. Astronomers used light from the entire galaxy to make that measurement. Now, using the Atacama Large Millimeter/submillimeter Array in Chile for about two months in 2018, Inoue and colleagues have measured more subtle differences in how that light is shifted across the galaxy’s disk. The new data show that, while all of JD1 is moving away from Earth, its northern part is moving away slower than the southern part. That’s a sign of rotation, the researchers report in the July 1 Astrophysical Journal Letters. JD1 spins at about 180,000 kilometers per hour, roughly a quarter the spin speed of the Milky Way. The galaxy is also smaller than modern spiral galaxies. So JD1 may be just starting to spin, Inoue says. The James Webb Space Telescope will observe JD1 in the next year to reveal more clues to how that galaxy, and others like ours, formed (SN: 10/6/21).
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Cosmology & The Universe
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MIT postdoctoral researcher Daniele Michilli says it was a great feeling when he was looking over the data from a radiotelescope and an unusual burst of radio signals from a far-off galaxy caught his eye.“Imagine you are looking at a signal coming from a billion light-years away. It traveled all the universe and reached the telescope. You are the first human looking at it. And you are trying to solve a mystery that happened a billion light-years away,” he said in a video interview on Wednesday.Looking at the data, he said, was “like being Sherlock Holmes, with a crime scene in another galaxy.”The discovery of the three-second-long “fast radio burst,” reported last week by Michilli and other researchers in the journal Nature, was the latest addition to the growing body of research about the mysterious bursts of radio signals that were discovered only 15 years ago.Fast radio bursts are flashes of radio waves that typically last milliseconds. They are so powerful they can be observed billions of light-years away. (A light year is the distance light can travel in a year, or about 6 trillion miles.)After the first report in 2007, though, reports of others were slow to come in. As of 2019, researchers reported in a review article in The Astronomy and Astrophysics Review, less than a hundred had been found, even though researchers estimated that detectable bursts were occurring once every minute somewhere on the sky.Researchers got a big boost from the Canadian Hydrogen Intensity Mapping Experiment, a revolutionary new Canadian radio telescope. CHIME, which began operating in 2018, is designed to pick up radio waves emitted by hydrogen in the earliest stages of the universe. At the same time, it is an excellent detector of fast radio bursts. By mid-2020, it had detected well over 1,000 of them, according to the CHIME website. “So high an event rate promises major progress on this puzzling new astrophysical phenomenon,” the website said.The latest discovery was a product of the CHIME/FRB (Fast Radio Burst) Collaborative. MIT Professor Kiyoshi Masui is a member of the collaborative, and Michilli was studying the CHIME data as one of the researchers in Masui’s group.The burst, designated FRB 20191221A, is the longest-lasting fast radio burst. With nine regularly spaced signal peaks, about 0.2 seconds apart, it had the clearest periodic pattern detected to date, MIT said.Researchers suspect the signals could be coming from either a radio pulsar or a magnetar, two types of neutron stars, which are the collapsed cores of massive stars.Michilli said that it’s challenging, but possible, to use multiple telescopes to triangulate and locate the point on the sky where the signals are coming from. It’s been done in about 15 cases so far and it has been confirmed that the emissions were coming from other galaxies.CHIME, he said, is planning to build more telescopes in the United States and Canada so that every one of the fast radio bursts - currently several a day - can be located.Scientists are looking to learn more in two areas, he said. They want to know how the signals originate. “This is the first mystery, what produces these,” said Michilli.They also want to analyze distortions in the radio signals for telltale clues to the characteristics of the plasma - the gas-like collection of atoms and ions in space - that the signals traveled through on their incredibly long journey to Earth.The signals could, in that sense, be “probes to investigate the universe,” Michilli said.Martin Finucane can be reached at martin.finucane@globe.com.
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Cosmology & The Universe
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Almost immediately after scientists pointed the James Webb Space Telescope at the earliest galaxies in the universe, they were seeing things that didn't jibe with the rules of the cosmos.
These galaxies, viewed as they were only 500 to 700 million years after the Big Bang, seemed too massive and mature for their young age. It was like finding parents and children alongside their grandparents, who were themselves still children, two physicists said in a piece written for The New York Times.
“It’s bananas,” said Erica Nelson, an astrophysicist at the University of Colorado in Boulder, earlier this year in a statement. “You just don’t expect the early universe to be able to organize itself that quickly. These galaxies should not have had time to form.”
But new space research using advanced computer simulations suggests that the reason they appear mature through the infrared eyes of Webb, run by NASA and the European and Canadian space agencies, is not because they are uncharacteristically massive. Though a galaxy's brightness usually corresponds to its mass, small, less-developed galaxies could burn just as bright from irregular bursts of star formation, scientists say.
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A group of astrophysicists led by Northwestern University was able to demonstrate this without contradicting existing and widely accepted cosmology theories. The computer experiment was also able to reproduce the same number of bright galaxies at the cosmic dawn that astronomers observed with Webb. The research was published this week in Astrophysical Journal Letters.
"The key is to reproduce a sufficient amount of light in a system within a short amount of time,” said Guochao Sun, lead author on the study, in a statement. "A system doesn’t need to be that massive. If star formation happens in bursts, it will emit flashes of light. That is why we see several very bright galaxies."
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One of Webb's primary missions is to watch the universe "turn the lights on" for the first time by observing the ancient galaxies from the cosmic dawn — a period between 100 million years to 1 billion years after the Big Bang. In astronomy, looking farther translates into observing the past because light and other forms of radiation take longer to reach us.
Space is filled with gas and dust, which obscures the view to extremely distant and inherently dim light sources, but infrared light waves can penetrate the clouds. A NASA scientist once compared the infrared telescope's sensitivity to being able to detect the heat of a bumblebee on the moon.
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The Northwestern simulations revealed that the early galaxies could have undergone something the intellectuals refer to as — we kid you not — "bursty star formation." Rather than making stars at a steady clip like the Milky Way does, for instance, these galaxies churn out stars inconsistently, with a proliferation all at once, followed by stagnant periods sometimes stretching millions of years before another so-called burst.
Bursty star formation is common in low-mass galaxies, said Claude-André Faucher-Giguère, a professor of physics and astronomy at Northwestern, though it's unclear why.
"What we think happens is that a burst of stars form, then a few million years later, those stars explode as supernovae," he said in a statement. "The gas gets kicked out and then falls back in to form new stars, driving the cycle of star formation."
That might not happen in more massive galaxies because they have stronger gravity.
In that case, "When supernovae explode, they are not strong enough to eject gas from the system," Faucher-Giguère continued. "The gravity holds the galaxy together and brings it into a steady state."
Topics NASA
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Cosmology & The Universe
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The fight for dark skies
Recently, a large radio telescope detected low frequency radio waves from dozens of Starlink satellites in low Earth orbit. These unintended signals emanating from the onboard electronics could interfere with astronomical research.
These same satellites are also increasing the brightness of the night sky, which is significantly affecting optical astronomy research.
The culprit in both cases is satellite constellations, which are groups of artificial satellites working together as a system. The number of small satellites in low Earth orbit started growing rapidly in 2019, when companies such as SpaceX and OneWeb began to build the capacity for global internet coverage. Low orbits mean the signal travel times are shorter, but at such a close range it takes a lot of satellites to cover the planet. Because of shrinking launch costs, the satellite business is booming.
The numbers are eye-popping. There are around 10,000 satellites orbiting over our heads, a number that has doubled in the last four years. By 2030, the number is expected to grow to 75,000. SpaceX alone will account for 40,000 of these satellites as part of its Starlink constellation.
Radio astronomers are worried. Quiet radio skies have allowed some spectacular recent discoveries, such as the first image of a massive black hole. The radio interference from Starlink satellites falls near a frequency of 150 MHz, which is protected for astronomy by the International Telecommunication Union. There are no international regulations governing such emissions from spacecraft.
In contrast, terrestrial radio astronomy is well protected. In 1958, the National Radio Astronomy Observatory in West Virginia benefited from federal legislation that declared 13,000 square miles as the National Radio Quiet Zone. In this vast area, there are no cell towers, and the use of mobile phones and WiFi networks is highly restricted. This radio-quiet “oasis” is unique. Other radio observatories have avoided radio interference by choosing sites in remote parts of Australia, Chile and South Africa.
The good news is that the astronomers and the tech companies are talking. In January, the National Science Foundation and SpaceX signed an agreement to limit interference from the burgeoning number of their satellites.
For most of human history, the stars blazed in a dark night sky. But starting with the Industrial Revolution, and accelerating in the past 50 years, the stars have been disappearing as the population has grown and people have moved into cities flooded with artificial light. In the last decade, the night sky in North America and Europe has been getting brighter by 10 percent per year.
Optical astronomers are sounding the alarm about the impact of satellites on their research. Satellites catch the sun’s light when they are near the horizon and leave ugly streaks across deep images made with large telescopes. For the last 20 years, only 3 percent of Hubble Space Telescopes images were marred by satellite trails, but that could grow to 50 percent by the 2030s. Astronomy’s flagship survey tool, the Vera Rubin Observatory, is about to take data. One-third of its images may be affected.
There is some good news on this front too. In the agreement with the National Science Foundation, SpaceX has committed to changing the design and coatings on its satellites to make them invisible to the naked eye and reduce their impact on sensitive astronomical cameras. Meanwhile, astronomers are eying ever-more remote locations, like Antarctica and the far side of the moon.
Radio interference is an esoteric problem, but the loss of dark skies is something everyone can understand. More than 80 percent of the world and 99 percent of European and North American populations live under light-polluted skies. Most people in the industrialized world have never seen the beautiful arc of the Milky Way. A child born today in an urban or suburban setting will only be able to see 100 stars by his or her 18th birthday.
Chris Impey is a professor of astronomy at the University of Arizona. He is the author of hundreds of research papers on observational cosmology and education and popular books on black holes, the future of space travel, teaching cosmology to Buddhist monks, how the universe began, how the universe will end, and exoplanets. His massive open online courses have enrolled over 400,000 people.
Copyright 2023 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
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Cosmology & The Universe
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Space telescopes are all the rage right now, thanks to the immaculate first images of the cosmos beamed back to Earth by the James Webb Space Telescope. That 'scope is likely to deliver data and scenes from deep space for decades, but the fun doesn't stop there. In just over four years, NASA plans to launch its next next-gen space telescope: The Nancy Grace Roman Telescope.In a press release on Tuesday, NASA said SpaceX has won the launch contract and Roman will be launching on a Falcon Heavy and the date for go is currently listed as October 2026.Roman, previously known as the Wfirst telescope, will look at the universe in infrared, just like Webb does. The mission's primary objectives are to probe the nature of dark energy and dark matter in the universe, but it also includes a specialized instrument known as a "coronagraph" that can block out light from distant stars and detect exoplanets in orbit around them. Roman isn't an upgrade over Webb, but it will provide a look at the universe that is, according to NASA, a ten-fold improvement over Hubble. The telescope will sit at the Lagrange point, L2, a million miles from Earth -- just like Webb does. Basically, the two telescopes will be neighbors. NASA's Wide Field Infrared Survey Telescope (WFIRST) is now named the Nancy Grace Roman Space Telescope, after NASA's first Chief of Astronomy. NASA Entrusted with the task of delivering Roman to L2 is SpaceX's Falcon Heavy, the most powerful rocket currently in operation, chalking up over 5 million pounds of thrust at liftoff.The monstrous rocket hasn't been used since it's third flight in June 2019, when it launched various Department of Defense satellites to orbit in what the company called "the most difficult launch ever." The rocket contains three boosters -- a core and two side boosters -- that return to Earth for re-use. However, in all three launches so far, the core booster has been lost. SpaceX's next Falcon Heavy launch will occur in August, with two more launches planned for 2022. Now playing: Watch this: James Webb Space Telescope: First Images Explained 10:54
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Cosmology & The Universe
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LIVE UPDATESIt's the highest resolution image of the universe ever taken.Last Updated: July 12, 2022, 11:18 AM ETThe first full-color image from NASA's James Webb Space Telescope has been released.The images, the full set of which will be released Tuesday morning, will be the deepest and highest resolution ever taken of the universe, according to NASA.The telescope will help scientists study the formation of the universe’s earliest galaxies, how they compare to today’s galaxies, how our solar system developed and if there is life on other planets.A new image released by NASA from the James Webb Space Telescope shows a planetary nebula, known as the Southern Ring Nebula, as it is dying.The image shows a star expelling gas and dust as it dims with the ionized gas seen in "unprecedented detail."According to NASA, the star at the center of the image has been sending out rings of gas and dust for thousands of years in all directions and the telescope revealed it is "cloaked" in dust.NASA has begun releasing the long-awaited new images from the James Webb Space Telescope.One of the first images revealed during a televised broadcast Tuesday from NASA's Goddard Space Flight Center in Greenbelt, Maryland, shows a graph of the atmospheric composition of WASP-96 b, the largest planet outside of our solar system.Officials explained that as the planet passes in front of star, the starlight filters through the atmosphere as it passed, which is broken down into wavelengths of light.The graph indicates the presence of water vapor, which is evidence that the planet had clouds, which were once thought not to exist there, NASA explained.The data also demonstrates, "Webb’s unprecedented ability to analyze atmospheres hundreds of light-years away," the space agency said.Ahead of the release Tuesday of the first images taken by the James Webb Space Telescope, NASA has revealed a list of the telescope's first targets.Among them is the Carina Nebula, which is one of the brightest nebulae in the sky -- according to the space agency -- and located about 7,600 light-years away.Other targets include WASP-96 b, the largest planet outside of our solar system, and the Southern Ring Nebula, which is a planetary nebula, or a cloud of gas that encircles a dying star.The telescope will also examine Stephan's Quintet, a group of five galaxies located 290 million light-years away and of which four are "locked in a cosmic dance of repeated close encounters," NASA said.The final target is the SMACS 0723, which is a cluster of galaxies that distorts the light of objects behind it and will allow scientists to look at planets, stars and other objects that would have been otherwise invisible to the human eye.President Joe Biden unveiled the first full-color image taken by the James Webb Space Telescope.The image, revealed during a press event held at the White House Monday and also attended by Vice President Kamala Harris, shows multiple galaxies.It is the highest-resolution image of the universe ever captured, officials said."Today is a historic day," said Biden. "It’s a new window into the history of our universe and today we’re going to get a first glimpse of the light to shine through that window."NASA Administrator Bill Nelson said the light seen on the image has been traveling for over 13 billion years.
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Cosmology & The Universe
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Stars could be sliced in half by "relativistic blades," or ultra-powerful outflows of plasma shaped by extremely strong magnetic fields, a wild new study suggests. And these star-splitting blades could explain some of the brightest explosions in the universe.
The study authors, based at the Center for Cosmology and Particle Physics at New York University, outlined their results in a paper published in September to the preprint database arXiv. The study has not yet been peer-reviewed.
The researchers were hunting for the origins of certain types of gamma-ray bursts (GRBs). GRBs are some of the most powerful explosions in the sky, but they typically occur so far away we can only see them as a brief but intense blip of excess gamma-ray radiation. Only a handful of known objects can generate the energies required to power a GRB, and so most astrophysicists assume that either black holes or magnetars are involved — likely when they are engaged in something violent like ripping a star apart. However, astronomers have struggled to explain why some GRBs fade away very slowly.
In the new study, the authors suggest that these lingering GRBs may occur when some massive stars die. The core of the star collapses, forming a neutron star, which is a city-sized ball of ultra-dense neutrons, surrounded by the heavy layers of hydrogen and helium. That neutron star can acquire an extremely strong magnetic field through rapid compression and rotation. This turns the neutron star into a magnetar, which hosts the most powerful magnetic fields in the known universe.
The newborn magnetar is surrounded by chaos. Its own gravitational pull draws the remaining atmosphere of the parent star onto it, but the intense radiation and magnetic fields whip that plasma around in a frenzy. In previous work, astronomers concluded that in this maelstrom, a jet forms along the spin axis of the magnetar, punching its way through the dying star.
But the authors of the new study realized that the magnetar's magnetic fields can also beam intense bursts of radiation along the magnetar's equator. Shaped by the extreme centrifugal forces of the rotating star, these beams of radiation form a blade that moves outward through the star at nearly the speed of light, carrying more energy than a supernova explosion.
This "relativistic blade" can perfectly bisect the star, slicing it in half on its way out, the study authors found.
The blade then travels for a distance well over several times the radius of the original star before it finally loses steam, potentially explaining some longer-lasting GRBs.
The star's fate is sealed. During the blade's travel, it picks up more and more material that eventually joins the blade in its outward journey. The blade also causes instabilities within the star itself that lead, eventually, to its demise.
For this study the researchers simply demonstrated that a relativistic blade could explain such GRBs. For their next step, the researchers plan to study how the blade evolves with time, and exactly how the ensuing stellar death unfolds.
That would enable them to identify key signatures of this type of explosion and determine if some GRBs scientists have previously observed can be explained with this model.
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Cosmology & The Universe
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"Earlier this year, after 15 years of searching, scientists finally heard the background hum of low-frequency gravitational waves that fill our universe," writes Space.com.
"Now, the hard work of searching for the source of these ripples in spacetime can begin." Currently, the primary suspects in this case are pairings of supermassive black holes with masses millions, or even billions, of times that of the sun. However, that doesn't mean that there isn't room for a few unusual suspects, which could potentially point us toward new physics....
[G]ravitational waves detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) express wavelengths that are thousands of miles (or km) in length and hold frequencies of milliseconds to seconds. The new gravitational waves detected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), by contrast, have wavelengths on a scale of trillions of miles (or km). This is similar to the distance between the sun and its neighboring star, Proxima Centauri, a staggering 20 light-years in length. Plus, NANOGrav gravitational wavelengths have frequencies on scales of years instead of mere seconds. Practically, what this means is scientists need to build over 15 years of NANOGrav data to confirm a low-frequency gravitational wave detection.
But, when it happens, it's worth the wait. That's because these results have the capacity to point us toward new information about our universe... "The detection of low-frequency gravitational waves means they're from very different sources to the LIGO and Virgo sources, which are stellar mass black holes and neutron star mergers," Scott Ransom, a National Radio Astronomy Observatory astronomer and former chair of NANOGrav, told Space.com... Ransom is part of a collaboration of researchers that believe low-frequency gravitational waves, including those detected by NANOGrav, may originate from a pretty incredible source. They could come from, the team argues, hundreds of thousands of supermassive black hole pairings that, over the 13.8-billion-year course of cosmic history, came close enough together that they've merged...
"For many decades, theorists have hypothesized that supermassive black hole binaries should produce a signal with characteristics just like what NANOGrav and other pulsar timing arrays are seeing," Luke Zoltan Kelly, a Northwestern University theoretical astrophysicist and NANOGrav researcher, told Space.com. "For most of the community, supermassive black hole binaries are a natural best guess for what's producing the gravitational wave background...." Zoltan Kelley pointed out to Space.com that besides binaries, there are a number of new models in cosmology and in particle physics that, under the right circumstances, could also produce a similar gravitational wave background to that detected by NANOGrav. For example, axion or 'fuzzy' dark matter, cosmic strings, inflationary phase transitions, and many others," the Northwestern astrophysicist said.
"What's really exciting about these possibilities is that each of these models is an attempt to explain some of the biggest current mysteries of our universe."
"Now, the hard work of searching for the source of these ripples in spacetime can begin." Currently, the primary suspects in this case are pairings of supermassive black holes with masses millions, or even billions, of times that of the sun. However, that doesn't mean that there isn't room for a few unusual suspects, which could potentially point us toward new physics....
[G]ravitational waves detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) express wavelengths that are thousands of miles (or km) in length and hold frequencies of milliseconds to seconds. The new gravitational waves detected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), by contrast, have wavelengths on a scale of trillions of miles (or km). This is similar to the distance between the sun and its neighboring star, Proxima Centauri, a staggering 20 light-years in length. Plus, NANOGrav gravitational wavelengths have frequencies on scales of years instead of mere seconds. Practically, what this means is scientists need to build over 15 years of NANOGrav data to confirm a low-frequency gravitational wave detection.
But, when it happens, it's worth the wait. That's because these results have the capacity to point us toward new information about our universe... "The detection of low-frequency gravitational waves means they're from very different sources to the LIGO and Virgo sources, which are stellar mass black holes and neutron star mergers," Scott Ransom, a National Radio Astronomy Observatory astronomer and former chair of NANOGrav, told Space.com... Ransom is part of a collaboration of researchers that believe low-frequency gravitational waves, including those detected by NANOGrav, may originate from a pretty incredible source. They could come from, the team argues, hundreds of thousands of supermassive black hole pairings that, over the 13.8-billion-year course of cosmic history, came close enough together that they've merged...
"For many decades, theorists have hypothesized that supermassive black hole binaries should produce a signal with characteristics just like what NANOGrav and other pulsar timing arrays are seeing," Luke Zoltan Kelly, a Northwestern University theoretical astrophysicist and NANOGrav researcher, told Space.com. "For most of the community, supermassive black hole binaries are a natural best guess for what's producing the gravitational wave background...." Zoltan Kelley pointed out to Space.com that besides binaries, there are a number of new models in cosmology and in particle physics that, under the right circumstances, could also produce a similar gravitational wave background to that detected by NANOGrav. For example, axion or 'fuzzy' dark matter, cosmic strings, inflationary phase transitions, and many others," the Northwestern astrophysicist said.
"What's really exciting about these possibilities is that each of these models is an attempt to explain some of the biggest current mysteries of our universe."
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Cosmology & The Universe
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After two years of data-taking and number-crunching, a team of astronomers has dropped a snapshot of, quite literally, cosmic proportions. It’s chock-full of stellar goodness: The image shows the reddish-brown dust clouds clumped along the centerline of our Milky Way teeming with over 3 billion pinpricks of light—nearly all stars, a faint neighboring galaxy here or there.
The project, based at the Harvard-Smithsonian Center for Astrophysics, is called the Dark Energy Camera Plane Survey, and aims to index celestial objects located in our galactic plane. In January, the researchers published their second data release in The Astrophysical Journal Supplement Series, making it the largest catalog, or index, of stars ever collected by a single instrument, and one of the few instances in which we’ve turned a camera toward the middle of our own galaxy. It’s a space selfie, if you will.
But while the stars are the showstopper, the other point of this survey is capturing the elusive substance that drifts among them: dust. Because dust masks light, it distorts our view of the cosmos. Knowing how much is out there can help astronomers filter its effects from their data, and more accurately gauge the chemistry and position of stars. Over the next decade, scientists will use this catalog to flesh out galactic dust maps, track down ancient star systems, and study the formation and structure of our Milky Way.
For the survey, the research team repurposed the Dark Energy Camera, or DECam, an optical instrument at the Cerro Tololo Inter-American Observatory in Chile that was originally built to study faint objects far away from the galactic plane. “We took this instrument that was made for cosmology,” says Eddie Schlafly, an astronomer at the Space Telescope Science Institute, “and we pointed it right at the center of the galactic plane, where there’s tons and tons of stars and dust and gas and nebulosity.” The goal, he says, was to resolve as many individual sources of light as possible.
That’s quite the tall order: Most astronomers stray from observing the galactic plane because it’s notoriously difficult to image. “The Milky Way is a spiral galaxy. So most of its stars are in a flat pancake,” says Andrew Saydjari, a physics graduate student at Harvard University who spearheaded the survey. Unfortunately for observers on Earth, we sit smack in the middle of that pancake. It’s easy to see above or below our plane in that disc, where the stellar haze is thin. But peering into the center of the galaxy, or backward to the outer edge, is tough because the view is crowded. “A lot of the stars can appear like they’re on top of each other,” Saydjari says.
Other stuff hanging around the galactic center doesn’t help. Some gas, for example, is hot enough to emit its own photons in a color similar to starlight’s. And dust can make celestial objects appear fainter and redder than they actually are. Both of these can skew astronomers’ measurements of stellar brightnesses and positions.
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Cosmology & The Universe
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Subsets and Splits
List Unique Topics
Simple retrieval of unique topics from the dataset, useful for basic exploration but lacks deeper insights.