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Why can't medical scientists collect data from a group of people and use the same human control group for every medical experiment in the future so that participants in a study don't have to risk taking a placebo? | The major issue with that is it wouldn't be a good control *because* of the lack of a group taking the placebo. When they do most trials they do them double blind. Neither the subject nor the doctor knows who is getting the real drug and who is getting a placebo (until afterwards, of course). | [
"In controlled experiments of medical treatment options on humans, researchers randomly assign individuals to a treatment group or control group. This is done to reduce the confounding effect of irrelevant variables that are not being studied, such as the placebo effect. \n",
"In medicine, anecdotal evidence is a... |
Why do lights dim briefly sometimes when lightning strikes nearby? | If lightning hits a power line or transformer, it could greatly increase the voltage of the lines relative to Earth ground, and a lot of equipment connected to those power lines would be damaged. Varisters or Transorbs are places across power line components to protect them form sudden increases in voltage. While these... | [
"During the American Physical Society's 2014 March meeting, research was provided that gave a possible explanation for the reason why bright lights sometimes appear during an earthquake. The research stated that when two layers of the same material rub against each other, voltage is generated. The researcher, Profe... |
why are animals and fauna no longer as large as they once were? what has changed about our world that mega fauna and mega animals no longer exist? | We don’t *actually* know but some theories are that temperature of the earth was the major factor for mammals getting so big. If the ambient temperature is lower, the heat/energy of a larger mammal is much easier.
For insects (and maybe plants), there was a much higher concentrations of oxygen in the atmosphere that... | [
"A 2019 study published in \"Nature Communications\" found that rapid biodiversity loss is impacting larger mammals and birds to a much greater extent than smaller ones, with the body mass of such animals expected to shrink by 25% over the next century. Over the past 125,000 years, the average body size of wildlife... |
why don't 'unincorporated territories of the united states pay taxes? why aren't they considered a state? | Well in the US we have a thing about taxing people who don't have representation in the body that decides what those taxes are. They aren't states either because the don't want to be, or Congress won't admit them, or both. | [
"Territories of the United States are sub-national administrative divisions overseen by the federal government. They differ from U.S. states and Native American tribes, which have limited sovereignty. The territories are classified by incorporation and whether they have an \"organized\" government through an organi... |
Ku Klux Klan's reaction to Hilter | [From a previous answer](_URL_0_):
So the history of the KKK and the Nazi movement isn't a particularly big one, but given the similarities - being largely centered around ideologies of racial exclusion - it shouldn't be a surprise that they did, occasionally, intersect.
As far as Nazi Germany itself goes, it isn't e... | [
"The Ku Klux Klan was a secret organization of whites that resisted what they saw as the excesses of Reconstruction. They sometimes terrorized and even assassinated Union League leadership. Founder Nathan Bedford Forrest grew uneasy about the group’s tendency to lawlessness, and disbanded it in the late 1860’s.\n",... |
how are open-world video game maps designed? | They actually do "draw" the world piece by piece. It's usually done by groups of people, not just one dude. They first make a rough terrain curves (hills, rivers, canyons...) then they just polish it till it looks really nice. Then they have to add all the props, like trees, buildings, people...
So yeah, they are act... | [
"Some open-world games, to guide the player towards major story events, do not provide the world's entire map at the start of the game, but require the player to complete a task to obtain part of that map, often identifying missions and points of interest when they view the map. This has been derogatorily referred ... |
Battle of Leuctra - the defeat the broke Sparta's power | **1/3: Historiography**
The Battle of Leuktra (371 BC) is notoriously difficult to reconstruct. As Pritchett once remarked with obvious exasperation, "there are more reconstructions of Leuktra than of any other ancient battle, and the end is not in sight." There are a number of philological and historiographical reaso... | [
"During the Corinthian War, Sparta faced a coalition of the leading Greek states: Thebes, Athens, Corinth, and Argos. The alliance was initially backed by Persia, which feared further Spartan expansion into Asia. Sparta achieved a series of land victories, but many of her ships were destroyed at the battle of Cnidu... |
why is drinking sea water lethal, but soups with massive sodium content are acceptable? | Because soups with massive sodium content are still much, much, ***MUCH*** less salty than sea water. That's not to say they're healthy, though, Americans eat way too much sodium as it is.
Edit: in fact, salt water is so salty, that getting a mouthful of it is known to cause immediate vomiting. It's happened to me be... | [
"Many canned soups, including Campbell's condensed and chunky varieties, contain relatively high quantities of sodium and thus are not desirable for those on low-sodium diets. However, Campbell's Chunky, Healthy Request and other soups, as well as their V-8 and Tomato juices, are claimed by Campbell's to contain re... |
How genetically dissimilar are different dog breeds? Could a Sheppard donate a kidney to a Lab? Could a Great Dane donate blood to a Chihuahua? | Great question! Both cats of different breeds and dogs of different breeds are of the same species (*Felis catus* and *Canis lupis familiaris* respectively). As such, they can act as donors within their own species of both blood and organs.
That being said, there are things that you have to watch out for.
1. When it ... | [
"Ullmann was a pioneer of renal transplantation research. In 1902, he performed the first successful renal autotransplantation in a dog. Reportedly, the kidney remained functional for five days. Soon afterwards, he was unsuccessful in trying the first renal xenotransplantation (cross-species transplant) between a g... |
why is it that whats politically correct sometimes isn't the same as the opinion of the majority? | Let's start off with a statement, society evolves towards increased compassion for all members of society. On the forefront of that evolution is radical thought that tends to be less judgemental of others. For example, native Americans are equal humans (1920s), women are equal humans (1940s), Blacks are equal humans... | [
"By solely acknowledging voting patterns, one cannot make an accurate conclusion as to the presence or absence of political polarization, because in the United States, there is a limited number of presidential candidates in the two-party system. To assume that the majority of voters are mostly or completely in agre... |
How can paper be sharp enough to cut through human skin? | Microscopically the edge of paper is like a saw blade rather than a razor, it has to slide along the skin in order to make the cut.
| [
"BULLET::::- Plastic blades are usually not very sharp and are mainly used to cut through vegetables without causing discolouration. They are not sharp enough to cut deeply into flesh, but can cut or scratch skin.\n",
"A clean cut through a thick stack of paper cannot be made with a traditional inexpensive sickle... |
is gordan ramsay actually a good chef? | There's not really an objective way to answer your question, tastes can certainly vary. His restaurants have earned 16 Michelin stars, which are pretty sought after, so you may take that as an endorsement. At least some of these stars have been earned while he has been head chef at a location. He's undoubtedly technica... | [
"Ramsay's reputation is built upon his goal of culinary perfection, which is associated with winning three Michelin stars. His mentor, Marco Pierre White noted that he is highly competitive. Since the airing of \"Boiling Point\", which followed Ramsay's quest of earning three Michelin stars, the chef has also becom... |
was Nero (the emperor) crazy from the beginning ? | I wrote [an answer](_URL_0_) to a similar question a few months back. The tl;dr of it is that Nero likely never was crazy, he was just really unfit to be an emperor of Rome. | [
"BULLET::::- \"The Adventures of Nero\": The title character Nero is named after Nero. In his first debut appearance the character believes himself to be the Roman emperor after drinking poisoned beer. Later he regains his sanity, but all characters kept referring to him as \"Nero\" from that moment onwards. In the... |
Are there any studies that show other species to be capable of lying/dishonesty? | This was a guestion in AMA with Sir David Attenborough:
In all your time of shooting nature programs, what is the most human thing you have ever witnessed an animal do?
A chimpanzee does in fact tell lies. If you can believe that. Also, when some Colobus monkeys find a very precious piece of food, it calls the alarm ... | [
"Researchers from the University of the Free State (UFS) in South Africa, while observing gelada during field studies, discovered that the monkeys were capable of 'cheating' on their partners and covering up their 'infidelity'. A non-dominant male would mate surreptitiously with a female, suppressing their normal m... |
I was spinning in my chair today (question about centripetal and -fugal forces.) | The construction of the inner ear (see [semicircular canals](_URL_0_)) allows you to detect the direction of acceleration. Once the turbulence in your inner ear settles, you will perceive yourself to be at rest as long as you don't feel acceleration, ignoring the sorts of small details mentioned in other comments. | [
"In Newtonian mechanics, the centrifugal force is an inertial force (also called a \"fictitious\" or \"pseudo\" force) that appears to act on all objects when viewed in a rotating frame of reference. It is directed away from an axis passing through the coordinate system's origin and parallel to the axis of rotation... |
In the 1970s UK sitcom Fawlty Towers, a few guests are shown to live permanently at the hotel. Was this common during this time? What factors led people to choose life in a hotel, and did this have a long history? | Hotel living has a *long* history--the *Eloise* books by Kay Thompson are probably the most famous example. I can talk a little bit about some of the earlier history, specifically, hotel living in Paris!
*(This is adapted from several of my earlier answers with some new stuff thrown in).*
Paris is the City of Lights.... | [
"The hotel's heyday was in the early 20th century, when it played host to royalty, politicians and film stars as well as staging many dinners, concerts and dances in the Grosvenor Suites. King George VI, Winston Churchill, Neville Chamberlain, Charlie Chaplin, James Cagney and Joe Louis attended functions or stayed... |
Why did 20th amendment required 3/4 of the states to be ratified? | I think a couple of things are getting mixed up here.
For the process of amending the Constitution, as laid out in the 1787 document (Article V), here is the original language:
> The Congress, whenever two thirds of both Houses shall deem it necessary, shall propose Amendments to this Constitution, or, on the Appli... | [
"To become valid as part of the Constitution, the Twenty-third Amendment needed to be ratified by the legislatures of three-quarters of the states (38, following admission of Alaska and Hawaii to the union in 1959) within seven years from its submission to the states by Congress (June 16, 1967). President Eisenhowe... |
What do we know about the fowl of the roman empire? | Fortunately there is a cook book from the late 4th or early 5th century CE. That book is Apicius. Keep in mind these recipes would have been for the upper class of society. There is a section on fowl which includes chicken, pheasant, goose, duck and doves. It also includes ostrich and peacock along with a few others. I... | [
"Caltrops were known to the Romans as \"tribulus\" or sometimes as \"murex ferreus\", the latter meaning 'jagged iron' (literally 'iron jagged thing'). They were also used in the Battle of Carrhae in 53 BC.\n",
"Pliny reported in \"Natural History\" that a grub which he gives the name \"cossus\" was considered a ... |
the plot of the legend of zelda series | It's hard to attribute a chronology to Zelda, though some aspects can be assumed ( like Wind Waker seems to be a post-apocalyptic Hyrule, the Great Sea having flooded the world ), and each of the games has similar themes for the most part. Seeing as Link is the "hero of time", I always saw the series as two omnipresent... | [
"The story of \"The Legend of Zelda\" is described in the instruction booklet and during the short prologue which plays after the title screen: A small kingdom in the land of Hyrule is engulfed by chaos when an army led by Ganon, the Prince of Darkness, invaded and stole the Triforce of Power, one part of a magical... |
What causes the double sonic boom of Falcon rockets landing? | Practically all objects that breaks the sound barrier cause a double sonic boom. First at the front of the object, where it is pushing away the air, and second at the end of the object, where it stops pushing away the air. At both these points there is a big and rapid change in pressure.
The F9 actually creates three ... | [
"According to witnesses no sonic boom was heard. It is claimed that this was because of the short distance between the observers and the deafening sonic waves from the combined liquid and solid-fuel rockets used to propel the vehicle. Standing shock waves in the rocket exhaust produce continuous supersonic shock wa... |
In the UK, how did political power shift away from the nobility? | It was taken from the hands of the nobility in 1999 when Labour removed the rights of peers to sit in the House of Lords, which is the UK's second chamber.
92 hereditary peers are left there today, along with 26 Princes of the Church. The rest are members of political parties that were ushered while their party was in... | [
"The influence of the Crown was increased by the civil wars of the late fifteenth century, which destroyed the power of the great noblemen. Both houses of Parliament held little power during the ensuing years, and the absolute supremacy of the Sovereign was restored. The domination of the monarch grew further under... |
What's the science behind the Hiroshima and Nagasaki bombs? Why were they still airborne when they detonated? | Both the Hiroshima and Nagasaki bombs were devices meant to create a supercritical state in a mass of enriched uranium (Hiroshima) or plutonium (Nagasaki), which allowed for an explosive nuclear fission chain reaction. In more layman's speak, this means that they quickly created the conditions so that [splitting one at... | [
"In Europe and America the effects of the atomic bombs over Hiroshima and Nagasaki were not fully understood. The photos produced by Masao Horino contributed to the world wide cry for the bombs to never be used again.\n",
"Details of nuclear weapon design also affect neutron emission: the gun-type assembly Hirosh... |
what makes facebook so valuable? why would it be a 100 bn $ company? | They do have a product they sell, a very valuable one... You.
All those statuses, all those 'likes', all those location check-ins... That data isn't just there for your friends to see. It is organized and categorized and analyzed and creates an unbelievable source of data for directed advertising. You dump every det... | [
"Facebook ranked No. 76 in the 2018 Fortune 500 list of the largest United States corporations by revenue. Most comes from advertising. One analysis of 2017 data determined that the company earned per user from advertising.\n",
"Facebook did accept investments from companies, and these investments suggested fluct... |
is there an evolutionary benefit to the type of hair you have? | I can tell you that having really curly afro hair in the summer heat means that I can sick my fingers in my hair and it feels like there is a little private AC unit in there. It keeps my head cool, I imagine it does, and has for other afro haired humans who are almost entirely of recent African descent, where it would ... | [
"It has been hypothesised that, in an alternate type of mutation, positive selection for increased expression of the FGF5 protein was one of the contributing factors in the evolutionary loss of hair in cetaceans as they transitioned from the terrestrial to the aquatic environment.\n",
"Markus J. Rantala of the De... |
when nasa created the golden record that they sent with the voyager probe, how did they know that another intelligent species who found the probe would be able to read/play it? | They printed instructions on how to play the disk in pictograms onto the disk cover.
see this picture on the explaination of the pictograms
_URL_0_ | [
"Launched in 1977, the Voyager probes carried two golden records that were inscribed with diagrams depicting the human form, our solar system, and its location. Also included were recordings of images and sounds from Earth.\n",
"The Voyager Golden Records are two phonograph records that were included aboard both ... |
what's a tarif? | A tariff is a tax on imports or exports.
For example, if you have a 100% tariff on iron, that means someone wanting to import (or export) iron into your country must pay 100% of the value of the iron in taxes. | [
"In computing, tar is a computer software utility for collecting many files into one archive file, often referred to as a tarball, for distribution or backup purposes. The name is derived from \"(t)ape (ar)chive\", as it was originally developed to write data to sequential I/O devices with no file system of their o... |
How does hydrogen peroxide work to remove stains? | It either oxidizes the material responsible for the coloration to the point that it becomes water soluble and rinses away or until it no longer absorbs light in the visible spectrum (organic dyes absorb light in certain color bands based on the energy level of their electrons - adjust the electronics and you adjust the... | [
"Oxidation using hydrogen peroxide is often used as a low cost pyrogen destroying solution. The mechanism for this destruction is unknown, but hydrogen peroxide can easily be removed further downstream in the purification process, and is therefore a useful method of pyrogen removal. However, like acid-base hydrolys... |
How did the first century Greeks and Romans view women? Further, how was this different from how Christians treated women? | This is mainly about the upper classes, as a necessity mandated by our sources. But an extremely brief summary: Greek and Roman medical theory believed that women had not received enough heat in the womb, and thus had failed to mature into full humans, i.e. men. So women are considered inherently biologically inferio... | [
"Whereas neither the Jewish, nor the Roman family would warm the hearts of a modern feminist, the early Christians were sympathetic to women. Paul himself insisted in his early writings that men and women were equal. His letter to the Galatians was emphatic in defying the prevailing culture, and his words must have... |
what went down in the ows subreddit? | I only have a tenuous grasp of the situation, but what I gathered was that some dick (username: [TheGhostOfNoLibs](_URL_0_)) finagled his way into a moderator spot on [/r/occupywallstreet](/r/occupywallstreet). Several people were complaining that he directly opposes just about everything the OWS movement stands for, h... | [
"OWS Media Group, Inc. is a group of the Occupy Wall Street movement, which achieved media attention after filing a lawsuit to re-obtain control over the Twitter account, @OccupyWallStNYC, which was hijacked by one of tweetboat's former members and password holders, Justin Wedes.\n",
"On June 10, 2015, a post on ... |
Why is it human nature to enjoy the pain of others? | It is not human nature to enjoy the suffering of others, quite the opposite in fact. Empathy is the one of the very important reasons our society functions well.
Sometimes however, the relief that we are not the ones suffering can be mistaken for enjoyment.
In modern day it can be seen as weak or soft to be empathe... | [
"A benefit of tracing good to pleasure and pain is that both are easily understandable, both in oneself and to an extent in others. For the hedonist, the explanation for helping behaviour may come in the form of \"empathy\"—the ability of a being to \"feel\" another's pain. People tend to value the lives of gorilla... |
Is there an auditory processing disorder that is similar to dyslexia? | There is a disorder literally called Auditory Processing Disorder (APD) that is similar to Dyslexia. It is an abnormality in the processing of sound in the central auditory nervous system and it affects the brain’s ability to filter and process sounds and words. Most people that have Dyslexia also tend to have this dis... | [
"Dyslexia is thought to have two types of cause, one related to language processing and another to visual processing. It is considered a cognitive disorder, not a problem with intelligence. However, emotional problems often arise because of it. Some published definitions are purely descriptive, whereas others propo... |
How did James Maxwell determine that electromagnetic waves create their own medium? | To get the speed of light, you can take Maxwell's equations, assume there are no charges anywhere, and 'pluck' the electric or magnetic field and watch what happens. The solution to these assumptions is a wave propagating through the EM field at the speed *c*. Maxwell proposed that light might be an EM wave because thi... | [
"With the addition of the displacement current, Maxwell was able to hypothesize (correctly) that light was a form of electromagnetic wave. See electromagnetic wave equation for a discussion of this important discovery.\n",
"In 1864 Scottish mathematical physicist James Clerk Maxwell proposed a comprehensive theor... |
Does the electromagnetic spectrum abruptly stop at gamma rays.. or are there higher energy/shorter wavelengths out there? | No, there is no sharp cut off, though we don't have a standard term for super-high energy photons. Typical gamma rays from nuclear have energies of 10^(5) to 10^(7) eV. Astronomical sources can yield energies around 10^(13) eV, indicating that they coming from processes other than radioactive decay. If you can find ... | [
"In the few radio-loud Seyfert galaxies that have been observed, the radio emission is believed to represent synchrotron emission from the jet. The infrared emission is due to radiation in other bands being reprocessed by dust near the nucleus. The highest energy photons are believed to be created by inverse Compto... |
Monday Methods | An Indigenous Pedagogy | Another very fascinating write-up, thank you. I actually have a few questions.
In most threads on indigenous or marginalized/subaltern peoples of any kind, there is a common caveat that accompanies any historical answer on this subreddit. For example, from a recently excellent answer about Native American perceptions ... | [
"Critical Indigenous Pedagogy focuses on resisting colonization and oppression through education practices that privilege indigenous knowledge and promote indigenous sovereignty. Beyond schooling and instruction, CIP is rooted in thinking critically about social injustices and challenging those through education sy... |
why are some seasonal fruits, like apples, available all year round, but others aren't? | Seasonal fuits are grown in both the northern and southern hemispheres and shipped all over the world. A lot of summer fruits that are available in grocery stores in the winter in northern countries are grown in Chile, Argentina, New Zealand etc. The same is true of winter fruits that are available in grocery stores in... | [
"While the season usually lasts only 9 or 10 months, they are able to last all year round. However, due to some apples continuing to be grown in some orchards, and the fact that they can be refrigerated for some months, leads to the availability of the Gala apple year-round in some Australian markets. These usually... |
how do they fake apps/operating systems in movies/tv | Usually you would want to do it in post-production because screens don't film well due to different refresh rates. They may have prompts on the screen if the scene calls for it though. | [
"Virtual influencers are sometimes considered fake influencers too, given their profiles do not correspond to real individuals. It can be argued, however, their presence and role on the platform are different, in the sense they are not automated (bots) nor implemented with the purpose of generating fake likes, fake... |
why do game consoles not need a 3 prong plug with a ground wire but things like amplifiers and pcs do? | The 3rd prong is just an added safety precaution. To be approved by the UL anything with an exposed metal case needs to have the 3rd prong so if a wire inside the device comes loose and into contact with the case the current will go down the ground prong and not to you if you touch it. game consoles have plastic case... | [
"Historically, pinball machines have employed a central fixed I/O board connected to the primary CPU controlled by a custom microcontroller platform running an in-house operating system. For a variety of reasons that include thermal flow, reliability, vibration reduction and serviceability, I/O electronics have bee... |
How does the rate at which a star burns up scale with temperature? | Just taking some of the relationships from [here.](_URL_0_) We have:
- Lifespan is proportional to M^-2.5
- L is proportional to M^3.5
- L is also proportional to T^4
(where L is luminosity, T is temperature and M is mass). So combining all of these, we get lifespan is proportional to T^-10/3.5 or T^-20/7 . | [
"The surface temperature of a main sequence star is determined by the rate of energy production of its core and by its radius, and is often estimated from the star's color index. The temperature is normally given in terms of an effective temperature, which is the temperature of an idealized black body that radiates... |
how is downloading movies/books online any different than going to your local library to check out movies/books for free? | First sale doctrine applies to libraries, video rental outfits, etc.
From [Wikipedia](_URL_0_)
> The doctrine allows the purchaser to transfer (i.e., sell, lend or give away) a particular lawfully made copy of the copyrighted work without permission once it has been legally obtained. This means that the copyright ho... | [
"Used bookstores can range in size offering from several hundred to several hundred thousands of titles. They may be brick-and-mortar stores, internet-only stores, or a combination of both. A book town is a locale where numerous bookstores are located and serve as the town's main attraction to tourists.\n",
"The ... |
what would happen if somebody broke the nato treaty? | Sending military support is only one way NATO countries can show support. They can also provide financial aide, legal aide, or advisory aide.
Unless one NATO country attacked another, I can't imagine a situation where the other NATO countries wouldn't provide some sort of support, no matter how indirect. | [
"At the time the treaty was being negotiated, NATO had in place secret nuclear weapons sharing agreements whereby the United States provided nuclear weapons to be deployed by, and stored in, other NATO states. Some argue this is an act of proliferation violating Articles I and II of the treaty. A counter-argument i... |
Why are Hydrogen(1) and Helium(2) highly abundant in the universe, while Lithium(3) and Beryllium(4) not that much? | Production of lithium from helium is highly *Endothermic*, meaning that it consumes massive amounts of energy instead of creating it. Secondly the fact that it's endothermic results in a significant *Energy Barrier* that needs to be overcome, on top of the powerful electrical repulsion between nuclei.
The most likely ... | [
"According to modern cosmological theory, lithium—in both stable isotopes (lithium-6 and lithium-7)—was one of the three elements synthesized in the Big Bang. Though the amount of lithium generated in Big Bang nucleosynthesis is dependent upon the number of photons per baryon, for accepted values the lithium abunda... |
why does putting the air conditioner on 25°c in a cooling mode feel different from the same 25°c in heating mode? | The unit isn't putting out air at 25 C.
If it's in cooling mode, it's putting out very cold air until the ambient temperature reaches 25 C.
If it's in heating mode, it's putting out very warm air until the ambient temperature hits 25 C. | [
"Switching the direction of heat flow, the same system can be used to circulate the cooled water through the house for cooling in the summer months. The heat is exhausted to the relatively cooler ground (or groundwater) rather than delivering it to the hot outside air as an air conditioner does. As a result, the he... |
land bridges | Here's a NOAA map of the last ice age sea levels at their peak (trough) _URL_0_
| [
"A land bridge, in biogeography, is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and colonise new lands. A land bridge can be created by marine regression, in which sea levels fall, exposing shallow, previously submerged sections of continenta... |
what's the deal with tuxes, blazers, etc, when is each appropriate, what kind of occasions? | In descending order of fanciness:
- **[White Tie](_URL_2_)**, otherwise known as Evening Dress or Top Hat And Tails.
This is as formal as it gets in Western fashion, and is generally restricted to very high occasions like state dinners, royal functions or very formal balls and evening weddings. White Tie is strictly t... | [
"Blazers are worn with a wide variety of other clothes, ranging from a dress shirt and necktie to an open-necked polo shirt, or even just a plain T-shirt. They are seen with trousers of all colours and fabrics, from the classic white cotton or linen, to grey flannel, to brown or beige chinos, and also jeans.\n",
... |
How do weather satellites measure barometric pressure in the atmosphere from space? | Satellite radar systems can correlate a specific band of the electromagnetic spectrum with surface pressure, but according to my relatively limited knowledge of remote sensing, this technique is not commonly in use. Surface pressure is generally recorded in the ocean by anchored buoys, or potentially by [dropsondes](_... | [
"A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis to help find surface troughs, pressure systems and frontal boundaries.\n... |
Volume of Earths atmosphere? | The volume of Earth's atmosphere, using the [accepted definition of the edge of the atmosphere](_URL_0_) is approximately 5.18*10^19 m^3 . Not very useful without something to compare it to, but it's a place to start. | [
"The composition of Earth's atmosphere is largely governed by the by-products of the life that it sustains. Dry air from Earth's atmosphere contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and traces of hydrogen, helium, and other \"noble\" gases (by volume), but generally a variable amou... |
why do stores offer cash-out, if it seems like they don't make any profit off it. (they charge your card, and give you that amount in cash) | The store benefits by getting rid of physical money and using electronic funds transfer - less money to transport in an armoured truck, less loss if they are robbed | [
"The combination of these two factors means that the retailer can save money by offering the cashback service. It does not cost the retailer more in commission to add cashback to a debit card purchase, but in the process of giving cashback, the retailer can \"offload\" cash which they would otherwise have to pay to... |
Why does a single gas molecule which is hot rise above another one which is cool? | Metrics such as temperature describe the behavior of a system that is made up of components. These types of properties are termed emergent properties because they are derived from the behavior of the system as a whole and are not observable if you were to look only at the components.
So, for your specific question, i... | [
"Molecules, such as oxygen (O), have more degrees of freedom than single spherical atoms: they undergo rotational and vibrational motions as well as translations. Heating results in an increase in temperature due to an increase in the average translational kinetic energy of the molecules. Heating will also cause, t... |
how was space x able to build better rockets than nasa having less budget and experience? | I think the other people have missed the critical element here.
The critical element was the shift from disposable to reusable rockets. Now, to their great credit, NASA did make that move in the 70s with the space shuttle, but it was a bit too early, and the whole shuttle project was a bit of a logistical and politica... | [
"Congressional testimony by SpaceX in 2017 suggested that the unusual NASA process of \"setting only a high-level requirement for cargo transport to the space station [while] leaving the details to industry\" had allowed SpaceX to design and develop the Falcon 9 rocket on its own at substantially lower cost. \"Acco... |
Is it true that there have been 29 years free of war in all of human history? | It rather depends how you define things. If you count tribal disputes as wars, then it is unlikely there was ever a year without war. If you don't count tribal disputes, only formal armies, then the majority of human existence was without war. Mind you, most of human existence was before history. | [
"BULLET::::4. \"The Long Peace\" – The powers of 20th Century believed that period of time to be the bloodiest in history. This led to a largely peaceful 65-year period post World War I and World War II. Developed countries have stopped warring (against each other and colonially), adopted democracy, and this has le... |
Why didn't Hitler tell Mussolini about his plans to invade the USSR? | This one is kind of complex.
[Operation Barbarossa](_URL_2_) was the operation the Axis had planned to invade the Soviet Union. Nazi Germany had started to amass troops and equipment and had a pretty substantial force at the border in February of 1941. The original plan for the operation was to take place in May of 1... | [
"Mussolini first learned of Operation Barbarossa after the invasion of Soviet Union had begun on 22 June 1941, and was not asked by Hitler to involve himself. Mussolini took the initiative in ordering an Italian Army Corps to head to the Eastern Front, where he hoped that Italy might score an easy victory to restor... |
what is cancer? (specifically leukemia) | You, my ELI5 friend, are made of cells. Billions and billions of them, and they all have special jobs, shapes, and grow a different rates.
Sometimes we want cells to grow and divide a lot, like skin cells. And sometimes we don't want cells to grow and divide a lot, like brain cells. Each cell knows, because it is in t... | [
"Cancer is a group of fatal diseases that involves abnormal cell growth that can invade or spread to other parts of the body. They are usually caused by the accumulation of mutations in genes that regulate cell growth and differentiation. Majority of cancer, about 90-95%, are due to genetic mutations from environme... |
why are neanderthals always depicted with caucasian features? | Most, if not all, skeletons found of Homo neanderthalensis were found in Europe, especially places like France. As you may know, the people native to most places in Europe are Caucasian, including people like the Gauls (the tribe whose descendents make up a quite large percentage of native French people). | [
"Neanderthals are depicted as white-skinned, while Cro-Magnons are dark. Kurtén's skin color identification for both populations appears to agree with recent DNA studies, including those proposing the African origin of modern humans. His racial presentation of the Cro-Magnon is in contrast to Jean M. Auel's view in... |
Urban abandonment during late antiquity and the middle ages. | In the case of the Roman empire, there are several possibilities:
- The loss of North Africa to the Vandals. North Africa was the breadbasket of the Western Roman Empire, and without it, huge cities could no longer be supported. There was a similar but less dramatic depopulation of Constantinople after Egypt was lost ... | [
"However, there are traces of a resettling in the Middle Ages (12th century), when the ancient Roman walls were incorporated into those of a building forming part of the new inhabited hamlet also called \"Saint Eleuterio\", then in turn abandoned.\n",
"This development took place in the Late Middle Ages (13th to ... |
why doesn't the us military replace the m9. i'm sure there are better pistols out there. | Military firearms tend to have a long life. They like to standardize. When you've got a million of *anything* it's a big deal.
That said, they're [currently looking into a replacement](_URL_0_). These things can take time. Since handguns haven't fundamentally changed in decades, there's no major rush. | [
"The U.S. Army and Air Force are seeking to replace their M9s through the Modular Handgun System program. The House Armed Services Committee wants to terminate the program in favor of upgrading the M9. Program officials say buying a new pistol is the better option due to advances in handgun designs, the difficulty ... |
Hello AskHistorians, what are the most interesting or important books within your specialty, and what are they about? I am a teacher, creating a recommended/optional reading list for highly motivated students. Thank you! | Updating a list I wrote earlier for a request for resources on North Korea and the Kim regime:
- **Refugee account:** *The Aquariums of Pyongyang* by Chol-Hwan Kang and Pierre Rigoulout. A terrifying account of the Yodok concentration camp where the families of political prisoners are/were sent for punishment. Yodok ... | [
"Expert authors dissect, simplify and explain each topic to help readers achieve greater success in their business and home lives. Each book is short, snappy and easy-to-read, yet bursting with instantly actionable takeaways.\n",
"The books cover a wide range of topics, many to do with crafts, tools, music and ot... |
apparently there are tens of thousands of illegal immigrants from ireland in places like new york. isn't life very difficult for them? how do they earn money? can they get things like houses, driving licenses, healthcare, etc? | Housing: rent and pay cash. Find landlord that doesn't care if you're illegal.
Driver license, just don't get one. Take bus or subway. Or drive illegally and not get pulled over.
Healthcare, go to emergency room, pay in cash or don't pay at all | [
"There are however numerous incentives which draw foreigners to the US. Most illegal immigrants who come to America come for better opportunities for employment, a greater degree of freedom, avoidance of political oppression, freedom from violence, famine, and family reunification.\n",
"Some people go to traffick... |
If our moon causes our tides, and considering the size, wouldn't moons around a planet the size of Jupiter have tides that would flood entire continents? | (not my field of expertise) The moons of Jupiter have huge tidal forces. For instance take Io, it's the closest large satelite of Jupiter and it's tidal forces are so extreme that they heat the core of the moon, causing volcanos with plumes hundreds of kilometers high!
_URL_0_
(I remembered all of this from Arthur C ... | [
"If the Earth had no Moon, the ocean tides resulting solely from the Sun's gravity would be only half that of the lunar tides. A large satellite gives rise to tidal pools, which may be essential for the formation of complex life, though this is far from certain.\n",
"Atmospheric tides are also produced through th... |
why do most aeroplane hangars have curved roofs regardless of their size? | Actually it is for strength. An arch is incredibly strong and puts far less strain on the materials than a flat surface. | [
"The rectangular hangar accommodates 10 planes, and is still in use today. The building is made of brick and has a concrete foundation. The roof is gabled, and the walls are parapeted. The end walls are capped by pent roofs and decorative brick panels framed by stucco. The north and south ends contain eight large s... |
What is the mythological precedent for Jesus's single resurrection? | To quote Mettinger's [The Riddle of Resurrection](_URL_0_), which is probably the best survey of ANE gods and resurrection (Baal, Dumuzi-Tammuz, Adonis, Melqart-Heracles, Osiris, Eshmun-Ascelpius):
> The dying and rising gods were closely related to the seasonal
cycle. Their death and return were seen as reflected i... | [
"Rahner states that the death and the resurrection of Jesus are two aspects of a single event not to be separated, even though the resurrection is not a historical event in time and place like the death of Jesus. What the Scripture offers are powerful encounters in which the disciples come to experience the \"spiri... |
Since pi is irrational, is there a point in pi's decimals where there are 1 billion subsequent threes? | Probably, but not just because it's irrational. For example, the [Liouville constant](_URL_1_) is irrational but has only 0's and 1's in its decimal expansion.
However, pi is strongly conjectured to be a [normal number](_URL_0_). If this is the case, you certainly can find a billion 3's in a row in its decimal expansi... | [
"as it sometimes is, the ellipsis does not mean that the decimals repeat (they do not), but rather that there is no end to them. It has been proved that is irrational. Another well-known number, proven to be an irrational real number, is\n",
"In the 1760s, Johann Heinrich Lambert proved that the number (pi) is i... |
how are the nsa intercepting my data? | > Assuming I am US, by what method did the NSA just get hold of either/both the credit card details and travel information?
So the NSA is a spying agency, that also is involved in technical standards. They have court oversight through FISA, who can issue warrants that compel companies to turn over data.
Lets walk... | [
"All intercepted data go to the NSA headquarters in Fort Meade, Maryland, where a program called XKeyscore processes them and sending them to different so-called \"production lines\" that deal with targets, like counterterrorism or specific countries. These processed data are stored in different NSA databases like ... |
why does increased air flow extinguish flames? wouldn't you be adding the necessary ingredients? | Yer not alone in askin', and kind strangers have explained:
1. [ELI5: Why can air both extinguish and stoke up a fire? ](_URL_2_)
1. [ELI5: Why does blowing air on a small flame put it out, but doing the same on a big fire only fuels it? ](_URL_1_)
1. [ELI5: Why does blowing on a flame put it out, but glowing on coals... | [
"Oxygen is not flammable, but when it is present in increased concentrations it will enable fires to start much more easily. Once a fire has started, if supplemental oxygen is present it will burn more fiercely, based on the principle of the fire triangle. Materials that do not burn in ambient air may burn when the... |
why do people feel comfortable with themselves in the mirror, but hate themselves in flipped pictures? | Short answer: Because mirrors show a mirrored version of your face that you are used to/comfortable seeing. Photographs show a "correct" version of your face where it is not mirrored and it looks off to the person who perceives sees their face in a mirror on a regular basis
_URL_0_ | [
"This psychological effect is often used in the cinema, where an actor will be shown apparently looking at himself or herself in the mirror. What viewers see is different from what the actor sees, because the camera is not right behind the actor, but the position of the actor is often chosen so that his or her imag... |
If I could fly and I flew upwards really slowly, could I escape the earths atmosphere? | The term escape velocity refers to the speed you need to never fall back down to the Earth, assuming you stop pushing on your craft. If you can somehow continue to travel with a constant force away from the Earth, there is nothing stopping you from coming back down. Real craft will eventually run out of fuel, and thus ... | [
"As a tool for learning to control the body flight, there is a vertical wind tunnel, which makes it possible to fly in the air, simulating free fall due to the created air flow (on average, about 190 km/h).\n",
"In most situations it is impractical to achieve escape velocity almost instantly, because of the accel... |
American WW1 vet grave markings. | That's his unit. Company A, 13th Machine Gun Battalion.
See page 76 of this PDF
_URL_0_ | [
"When their remains were recovered after the war, Farrow, Hallmark and Meder were buried with full military honors at Arlington National Cemetery. Spatz was buried with military honors at National Memorial Cemetery of the Pacific.\n",
"The cemetery is an official Commonwealth War Grave Cemetery containing 48 memo... |
-if lance armstrong and his generation were doped to the gills how is it that this generation of cyclists is breaking their records absent significant technology advances and without drugs. | what records are you referring to exactly? if we're talking about the time it takes to climb Ventoux or Alpe d'Huez, [those times have actually gotten markedly worse since the doping crackdown](_URL_2_). in both cases, the best certifiably clean result isn't in the top 10 times up those climbs. or the top 20 (i'm looki... | [
"In 2009 director Alex Gibney set out to film \"The Road Back\", a documentary on cyclist Lance Armstrong's comeback year after a four-year retirement from the sport. Three years later, on October 2012, a doping investigation led to his lifetime ban from competition and the stripping of his seven Tour de France tit... |
why do people think that jeffrey epstein’s death seems like a coincidence? | At this point he was ready to bring down the people around him with him. He was a liability for all of the guilty elites that took advantage of his services. He already almost died once due to a cop beating him senseless, so this isn’t that big of a surprise. | [
"Epstein died of an overdose of Carbitral, a form of barbiturate or sleeping pill, in his locked bedroom on 27 August 1967. He was discovered after his butler had knocked on the door and then, hearing no response, asked the housekeeper to call the police. Epstein was found on a single bed, dressed in pyjamas, with ... |
why do bad smells seem to be so much more resilient than good ones? | I would assume that it is because bad smells are most often things that can negatively affect our health, like feces and rotting food and we should avoid as long as it is around.
The running shoes example doesn't exactly fit, although that may be due to cultural/evolutionary distance from apes in the same way that sw... | [
"Smell disorders can result in the inability to detect environmental dangers such as gas leaks, toxins, or smoke. In addition to safety, nutritional and eating habits can also be affected. There is a loss of appetite because of unpleasant flavor and fear of failing to recognize and consuming spoiled food. A decreas... |
when i bend my little finger, why do my other fingers also move? | What happens between the pinky and ring finger is nerve signals sent to the pinky get picked up by the ring finger because your brain can't actually control the pinky very accurately so to do more it sends signals intended for the ring finger. All of your fingers do this to a degree. Try extending all your fingers, and... | [
"Thumb twiddling is an activity that is done with the hands of an individual whereby the fingers are interlocked and the thumbs circle around a common focal point, usually in the middle of the distance between the two thumbs.\n",
"You should hold the other two fingers slightly bent, not completely straight. This ... |
If the gene that causes dwarfism is dominant why is it that the percentage of the general population that have this dominant gene is not higher? | Inheriting two copies of the gene usually leads to death in infancy [1], and a lot of achrondroplasic dwarfs have chronic pain, which would cause a general decrease in "fitness" (in the Darwinian sense). It seems fair to say it probably puts people at a pretty serious sexual disadvantage as well.
1. _URL_0_ | [
"As the genetic mutations that cause dwarfing occur in many species, dwarf animals can be the offspring of normal-appearing animals. Even in breeds which have not been selected for dwarfing, some genetic lines may show a tendency to produce dwarfs, which may be encouraged by deliberate breeding. This often takes th... |
Can a strong enough electric field penetrate Faraday cage? | A Faraday cage works because the electrons in the cage respond to an external electric field and re-arrange themselves naturally to create an equal and opposite field.
Hypothetically, if you had a large enough externally applied field that all the free electrons moving from one side to the other does not produce a lar... | [
"Faraday cages cannot block stable or slowly varying magnetic fields, such as the Earth's magnetic field (a compass will still work inside). To a large degree, though, they shield the interior from external electromagnetic radiation if the conductor is thick enough and any holes are significantly smaller than the w... |
Why is steel stronger than pure iron? | It all comes down to grain structure. Neither steel nor iron is a completely homogenous solid. A single crystal of metal can deform easily along the crystal axes; but if your metal is made up of a large number of small crystalline regions that are oriented randomly, they can't all deform in the same way and the bulk ma... | [
"Steel has much higher strength than wrought iron and allowed long span bridges, high rise buildings, automobiles and other items. Steel also made superior threaded fasteners (screws, nuts, bolts), nails, wire and other hardware items. Steel rails lasted over 10 times longer than wrought iron rails.\n",
"Iron is ... |
in court how do they compensate swearing the oath on bibles for people who arent religious or are not christian? | In the US, very few jurisdictions have people swear on bibles anymore. Those that do offer alternates to non-Christians. Some religions, like the Jehovah's Witnesses, who do not allow swearing, are allowed to affirm instead.
Note there is no legal significance to swearing on the bible or any religious book, it is pu... | [
"On May 24, 2007, Superior Court Judge Paul Ridgeway ruled that people of non-Christian faiths must be allowed to use religious texts other than the Christian Bible when being sworn in as jurors or witnesses in state court proceedings. Though the state had 30 days to decide to appeal the ruling, it took no action.\... |
What is it about Jamaican culture - opposed to other Caribbean nations - that produced so much extraordinary music? | Not to stifle discussion, but /u/hillsonghoods wrote [some fantastic replies to a similar question](_URL_0_) of mine which I'd recommend checking out. | [
"Jamaica's most popular musical forms are reggae and dancehall. There are also others such as \"dub poetry\" or chanted verses, Ska, and Rocksteady, with its emotionally charged, celebrative beat. Jamaican Americans also listen to a great variety of other music such as: jazz, calypso, soca, ska, rap, classical musi... |
What do we know about the Helots before they were enslaved by the Dorians/Spartiates? Did they ever manage to liberate themselves? | The ancient sources for helots are of such paucity and quality that scholars keep getting to diametrically opposite conclusions about who they were, what was their servial status, and the timing of their servitude. If you're interested in Helotry, I'd recommend this [collection of essays](_URL_0_), edited by Susan E. A... | [
"In the \"Bibliotheke\", \"Dorus received the country over against Peloponnese and called the settlers Dorians after himself.\" According to Karl Kerenyi, the Dorians recalled that three times Heracles had aided their \"oldest king\", Aigimios, \"under whom they had not yet emigrated to the Peleponnesos.\" Kerenyi'... |
how do we get propane and other gases from the ground? | We refine crude oil which contains gases in the oil(similar to carbonated beverages but less fizzy) and can undergo chemical reactions which will take bigger molecules and break them down into smaller molecules, like propane, which we then seperate out. | [
"Propane and butane are gases at atmospheric pressure that can be liquefied at fairly low pressures and are commonly known as liquified petroleum gas (LPG). Propane is used in propane gas burners and as a fuel for road vehicles, butane in space heaters and disposable cigarette lighters. Both are used as propellants... |
Does picking up a radio signal with a antenna reduce the power of the signal, even minimally? | Substitute "radio signal" with "sunlight" and "antenna" with "solar cell".
You assume that there's such thing as _the_ power of the signal, as a property of the emitter that everyone has direct access to. No, radio waves are not fundamentally different from light, so what you have instead is independent power of the s... | [
"So much wasted power is not acceptable in a transmitting antenna, however in a receiving antenna the inefficiency is not important at frequencies below about 15 MHz. At these lower frequencies, atmospheric noise (static) and man-made noise (radio frequency interference) even in the weak signal from an inefficient ... |
Does running through the rain make you more or less dry than walking? | If you look at this problem by trying to figure out your wetness as you walk through the falling rain, then it can be pretty tough. But it actually becomes easier if you look at it from the frame of reference of the falling rain. In this reference frame, the rain is just sitting there, still, and the ground is moving u... | [
"Running is an effective way to reduce stress, anxiety, depression, and tension. It helps people who struggle with seasonal affective disorder by being more outside running when it's sunny and warm. Running can improve mental alertness and also improve sleep which is needed for good mental health. Both research and... |
why do stenographers use those tiny typewriters? | They're [stenotypes](_URL_0_) which are much faster than typing, but don't transcribe speech directly into readable English but into a form of shorthand.
Why? It's quicker - the words are formed with "chords" rather than letter at a time. | [
"A number of typographical conventions originate from the widespread use of the typewriter, based on the characteristics and limitations of the typewriter itself. For example, the QWERTY keyboard typewriter did not include keys for the en dash and the em dash. To overcome this limitation, users typically typed more... |
how did the wwii enigma code machines work? | It's pretty cool, actually. I'll start with the basics. Each letter on the keyboard is connected, or paired, to another letter. So, if you press the A key, for example, you might see K light up. Similarly, if you press K, you'll see A light up. So, if you were to press H-E-L-L-O, you might get something like T-W-I-I-M.... | [
"In the lead up to World War II, the Germans made successive improvements to their military Enigma machines. By January 1939, additional rotors had been introduced so that there was a choice of three from five (i.e. 60 wheel orders) for the army and airforce Enigmas, and three out of eight (336 wheel orders) for th... |
the lean six sigma methodology | LEAN and 6sigma address two different aspects of factory production.
LEAN applies analysis to find the minimal cost steps needed to produce the item. It could mean the difference between giving a power tool to a worker instead of a manual tool. or having a conveyer delivery belt move the component to the worker in... | [
"Lean Six Sigma is a synergized managerial concept of Lean and Six Sigma. Lean traditionally focuses on the elimination of the eight kinds of waste/\"Muda\" classified as defects, over-production, waiting, non-utilized talent, transportation, inventory, motion, and extra-processing. Six Sigma seeks to improve the q... |
how do the "check to ensure you're not a robot" things actually work? what prevents computers from "clicking all pictures with a car"? i'm especially confused with the ones that dont require you to do anything except check the box. does somebody have an explaination? | It checks the way that the person clicks the button (path, speed, etc) to determine if the clicker is indeed a human | [
"Machine checks are a hardware problem, not a software problem. They're often the result of the overclocking or overheating, causing errors, or hitting a thermal limit where the CPU must shut itself down to avoid permanent damage. But they can also be caused by bus errors introduced by other failing components, inc... |
how did mayweather win that fight? | Pacquiao was the aggressor for most of the fight, and he swung a lot more. The crowd was clearly on his side, and Mayweather rarely drove forward.
But these things don't matter to the judges, or at least they shouldn't. Who was better at landing punches, who dictated the pace, who did the most damage, these things ma... | [
"Having recovered from Pacquiao's big hit in the previous round, Mayweather won the early exchanges of the fifth round. Pacquiao remained on the offensive, but was unable to land any big punches. Mayweather upped his activity and won the round in the eyes of the three judges. Pacquiao came out aggressive in the six... |
at the large hadron collider, how do the scientists get the 'right' protons into the machine? | You're overthinking the way it actually works.
What happens is they use a source that generates literally billions and billions of protons, these are all then accelerated around the machine and then finally allowed to crash into each other. Most of them don't even hit each other and are just absorbed. If the scientist... | [
"The Proton Synchrotron Booster (PSB) is the first and smallest circular proton accelerator (a synchrotron) in the accelerator chain at the CERN injection complex, which also provides beams to the Large Hadron Collider. It contains four superimposed rings with a radius of 25 meters, which receive protons with an en... |
What was the origin and meaning behind the haircuts of Medieval Japan? | Frankly I only know of the common topknot ("Chonmage") which was mostly done as a way to ensure that the kabuto helmet would fit snugly on one's head. The idea was that the topknot would be able to fit through a small hole in the helmet. Over time, while this tradition was forgotten, as the bushi and local daimyo beg... | [
"In the early 1870s, in a shift that historians attribute to the influence of the West, Japanese men began cutting their hair into styles known as jangiri or zangiri (which roughly means \"random cropping\"). During this period, Asian women were still wearing traditional hairstyles held up with combs, pins and stic... |
(if your country has them) why do drinks in king-size cans cost less than the normal cans? | There are a lot of fixed costs in packaging drinks and the price of a bigger or smaller can may not make much difference. Most of an items price has nothing to do with the size.
I designed labels for a big box store once and learned that the difference in cost to make a 16oz can of soda and a 32oz can is often less th... | [
"In both Malaysia and Singapore, the most commonly found cans are 300 ml for non-carbonated drinks and 325 ml for carbonated drinks. Larger 330 ml/350 ml cans are limited to imported drinks where it would usually cost a lot more than local ones.\n",
"250 ml cans are the most common for soft drinks, but when accom... |
4 continuous hours in the sun results in a sunburn, but 4 hours broken up into 15 minutes chunks does not. | The explanations so far are not correct. 4 continuous hours of sunlight will give your damaged cells less time to repair DNA and less time to apoptose (safely die without causing inflammation).
4 hours spread out over increments gives your cells time to repair DNA and, if need be, apoptose irreparable cells in-between... | [
"Sunburn can occur in less than 15 minutes, and in seconds when exposed to non-shielded welding arcs or other sources of intense ultraviolet light. Nevertheless, the inflicted harm is often not immediately obvious.\n",
"Recurring yearly, the eruption can sometimes last longer than a few days if persistent and rep... |
what are these new-age solid-state batteries? how are they different from conventional batteries? | They're batteries that use solid electrodes or electrolytes instead of liquid.
They have potentially higher energy density, and are safer since they're not flammable. They also have longer lifespans and don't produce as much heat.
I think the problem at the moment is that they're not ready to be mass produced and so ... | [
"A solid-state battery is a battery technology that uses solid electrodes and a solid electrolyte, instead of the liquid or polymer gel electrolytes found in lithium-ion or lithium polymer batteries. Materials proposed for use as solid electrolytes in solid-state batteries include ceramics (e.g. oxides, sulfides, p... |
When I think of the legacy of dueling, I picture it as an exclusively male enterprise. Is this really the case? Or are there records of women dueling as well? | Not discouraging any new answers coming in, but you better believe that /u/Georgy_K_Zhukov wrote about [this topic already](_URL_0_). Hope it helps! | [
"In tennis, \"Battle of the Sexes\" is a term that has been used to describe various exhibition matches played between a man and a woman (or, in one case, a doubles match between two men and two women). Most famously, the term is used for a nationally televised match in 1973, held at the Houston Astrodome, between ... |
how does a bike roll down a hill (balance) with no assistance? | Conservation of angular momentum. The wheels of the bike are spinning on a particular plane, and they naturally "want" to continue spinning on that plane, so they resist any change in that motion. In this case they resist the bike tipping over due to gravity. The faster they are spinning (meaning the more momentum they... | [
"A cyclist executing a basic track stand holds the bicycle's cranks in a horizontal position, with his or her dominant foot forward. Track stands executed on bicycles with a freewheel usually employ a small uphill section of ground. The uphill needs to be sufficient to allow the rider to create backward motion by r... |
why (in the u.s) we are taxed twice, and in many cases a third time, on the same income? | There's nothing illegal for different taxation at different levels of government for different purposed. Different taxes are for different governing bodies, some are more regressive, some more progressive, some go to specific uses while others go to general revenue streams. The amount needed to be collected is the same... | [
"Taxes are most often levied as a percentage, called the \"tax rate\". An important distinction when talking about tax rates is to distinguish between the marginal rate and the effective tax rate. The effective rate is the total tax paid divided by the total amount the tax is paid on, while the marginal rate is the... |
the "internet" to someone from the 1950s | Basically just go over the history of computers so that each step is easy enough to imagine from the last:
You know adding machines? Well we've made them better. Much better. Instead of being mechanically constructed to do sums or other things with numbers we enter with some buttons we've extended them to be able to d... | [
"The history of the Internet begins with the development of electronic computers in the 1950s. Initial concepts of wide area networking originated in several computer science laboratories in the United States, United Kingdom, and France. The U.S. Department of Defense awarded contracts as early as the 1960s, includ... |
I was told that there is so much historical proof of jesus' ressurection that you can't claim it didn't happen, how true is this? | **Commenters:** Please keep our commenting rules in mind as you respond to this. We've already had to remove a lot of comments that weren't up to the standards of the subreddit.
**OP:** We actually have this question asked from time to time, or questions like it. You might be interested in these previous posts:
* [S... | [
"Many testified falsely against Jesus, but their statements did not agree. At last two witnesses said they had heard Him saying He would destroy that temple and in three days built another, not made with hands, (He really had meant the resurrection of His body, as a temple of the Holy Spirit, destroyed by others bu... |
Can we create artificial atmospheres? | It's hard, because planets are big.
Think about what an atmosphere is. It's an razor thin envelope of gas that wraps around the surface of a rocky planet. There's no way to *fake* that. You don't want an *artificial* atmosphere, so much as you are actually asking for a real *bona fide* atmosphere.
To give the moon a... | [
"There are two basic choices for an artificial atmosphere: either an Earth-like mixture of oxygen in an inert gas such as nitrogen or helium, or pure oxygen, which can be used at lower than standard atmospheric pressure. A nitrogen-oxygen mixture is used in the International Space Station and Soyuz spacecraft, whil... |
why do space craft enter the atmosphere at full velocity, requiring heat shields and risking burning up? | "at the expense of additional fuel"
That's a really big expense, both in cost and weight. Its just literally not economically viable right now to do it that way. Though things like space x are starting to work on it.
Right now it makes most economic sense to just let it burn and crash and rebuild it, because thats ho... | [
"Spacecraft that land on a planet with an atmosphere, such as Earth, Mars, and Venus, currently do so by entering the atmosphere at high speeds, depending on air resistance rather than rocket power to slow them down. A side effect of this method of atmospheric re-entry is aerodynamic heating, which can be highly de... |
the earth is about 4.5 billion years old, but at what physical point do scientists classify a planet's age as 0? | When it started to be a planet.
To be a planet, it needs to fit three criteria:
A planet is an object in orbit around the Sun with a diameter greater than 2000 km.
A planet is an object in orbit around the Sun whose shape is stable due to its own gravity.
A planet is an object in orbit around the Sun that is domina... | [
"The age of the Earth is estimated to be 4.54 ± 0.05 billion years This age may represent the age of the Earth's accretion, of core formation, or of the material from which the Earth formed. This dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric age... |
How much body heat do you lose in your legs compared to your arms? And in your hands and feet? | heat loss is fairly uniform throughout the body. | [
"The burn percentage in adults can be estimated by applying the Wallace rule of nines (see total body surface area): 9% for each arm, 18% for each leg, 18% for the front of the torso, 18% for the back of the torso, and 9% for the head and 1% for the perineum.\n",
"Normally, extremities such as the hands are lower... |
Theoretically could you implant cones into your eyes that would allow you to see colors you could previously not see? | Perhaps. Experiments have been done where new visual pigment proteins have been introduced into red-green colorblind monkeys, and afterwards the monkeys could distinguish colors that they were not able to previously. However, these experiments did not implant new cones into the monkey retinas. Instead new proteins were... | [
"Neitz further states that since apparently \"the neural circuits can handle even higher dimensions of color vision that could come from artificially adding a fourth cone type, it is possible that gene therapy could also be used to extend normal human color vision\", making human trichromats into tetrachromats.\n",... |
Was Russia/Stalin truly hoping to share the Europe with Germany/Hitler or was Stalin playing a waiting game? | First of all let me say that Stalin didn't leave a diary so we can't exactly say what his emotions or personal thoughts were with confidence. That said, he was probably neither of those things.
The idea that he locked himself in a room for 3 days is certainly not true. We do have a record of his itinerary of the firs... | [
"The Soviet Union was not invited to the critical Munich conference in late September 1938, where Britain, France and Italy appeased Hitler by giving in to his demands to take over the Sudetenland, a largely German-speaking area of Western Czechoslovakia. Distrust was high in all directions. Leaders in London and P... |
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