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13. Cloud Structure on Saturn. In this Cassini image, colors have been intensified, so we can see the bands and zones and storms in the atmosphere. The dark band is the shadow of the rings on the planet. (credit: NASA/JPL-Caltech/Space Science Institute) Saturn has one anomalous cloud structure that has mystified scien... |
photographed by Voyager in 1989. The blue color, exaggerated with computer processing, is caused by the scattering of sunlight in the planet’s upper atmosphere. (credit: modification of work by NASA) Unlike Uranus, Neptune has an atmosphere in which convection currents—vertical drafts of gas—emanate from the interior,... |
parallel to the equator. These bands are semi-permanent features, although they shift in intensity and position from year to year. Consistent with the small tilt of Jupiter’s axis, the pattern does not change with the seasons. More fundamental than these bands are underlying east-west wind patterns in the atmosphere, ... |
42-year periods of sunlight and darkness have little effect. In fact, Voyager measurements show that the atmospheric temperature is even a few degrees higher on the dark winter side than on the hemisphere facing the Sun. This is another indication that the behavior of such giant planet atmospheres is a complex problem... |
it has continued to shrink, raising speculation that we may see its end within a few decades. Figure 11.19. Jupiter’s Great Red Spot. This is the largest storm system on Jupiter, as seen during the Voyager spacecraft flyby. Below and to the right of the Red Spot is one of the white ovals, which are similar but smaller... |
giant storms formed at latitude 20° S, had the same shape, and took up about the same fraction of the planet’s diameter. The Great Dark Spot rotated with a period of 17 days, versus about 6 days for the Great Red Spot. When the Hubble Space Telescope examined Neptune in the mid-1990s, however, astronomers could find n... |
Voyager, Galileo, and Cassini spacecraft. Voyager 2, perhaps the most successful of all space-science missions, explored Jupiter (1979), Saturn (1981), Uranus (1986), and Neptune (1989)—a grand tour of the giant planets—and these flybys have been the only explorations to date of the ice giants Uranus and Neptune. The ... |
cnx.org/content/col11992/1.8 Chapter 11 The Giant Planets 403 FOR FURTHER EXPLORATION Articles Jupiter Aguirre, Edwin. “Hubble Zooms in on Jupiter’s New Red Spot.” Sky & Telescope (August 2006): 26. Beatty, J. “Into the Giant.” Sky & Telescope (April 1996): 20. On the Galileo probe. Beebe, R. “Queen of the Giant Storms... |
://Solarsystem.nasa.gov/planets/jupiter Nine Planets Site: http://nineplanets.org/jupiter.html Planetary Sciences Site: http://nssdc.gsfc.nasa.gov/planetary/planets/jupiterpage.html Saturn NASA Solar System Exploration: http://Solarsystem.nasa.gov/planets/saturn Nine Planets Site: http://nineplanets.org/saturn.html Pla... |
:52). Jupiter: The Largest Planet: http://www.youtube.com/watch?v=s56pxa9lpvo. Produced by NASA’s Goddard Space Flight Center and Science on a Sphere (7:29). COLLABORATIVE GROUP ACTIVITIES A. A new member of Congress has asked your group to investigate why the Galileo probe launched into the Jupiter atmosphere in 1995 ... |
this problem? 3. Explain why visual observation of the gas giants is not sufficient to determine their rotation periods, and what evidence was used to deduce the correct periods. 4. What are the seasons like on Jupiter? 5. What is the consequence of Uranus’ spin axis being 98° away from perpendicular to its orbital pl... |
to substantial internal heat sources for Jupiter and Saturn. Since these two objects generate much of their energy internally, should they be called stars instead of planets? Justify your answer. 25. Research the Galileo mission. What technical problems occurred between the mission launch and the arrival of the craft ... |
outer solar system—too many to name individually or discuss in any detail. Astronomers anticipate that additional small moons await future discovery. We have also discovered a fascinating variety of rings around each of the jovian planets. Before the Voyager missions, even the largest of the outer-planet moons were me... |
captured by the planet they now orbit. (Perhaps the fact that they were not born locally will excuse their ill- mannered behavior.) Figure 12.2. Moons of the Solar System. This image shows some selected moons of our solar system and their comparison to the size of Earth’s Moon and Earth itself. (credit: modification o... |
consists of 11 rings and 27 currently known moons. The five largest moons are similar in size to the six regular moons of Saturn, with diameters of 500 to 1600 kilometers. Discovered in 1977, the rings of Uranus are narrow ribbons of dark material with broad gaps in between. Astronomers suppose that the ring particles... |
9 3.0 3.5 1.9 12 20 40 70 60 20 Callisto: An Ancient, Primitive World We begin our discussion of the Galilean moons with the outermost one, Callisto, not because it is remarkable but because it is not. This makes it a convenient object with which other, more active, worlds can be compared. Its distance from Jupiter is ... |
411 of the solar system in the apparent absence of interior forces to drive geological change. You might say that this moon was stillborn, and it has remained geologically dead for more than 4 billion years (Figure 12.3). Figure 12.3. Callisto. (a) Jupiter’s outermost large moon shows a heavily cratered surface. Astro... |
Ganymede is a differentiated world, like the terrestrial planets. Measurements of its gravity field tell us that the rock sank to form a core about the size of our Moon, with a mantle and crust of ice “floating” above it. In addition, the Galileo spacecraft discovered that Ganymede has a magnetic field, the sure signa... |
and triggered major convulsions on its crust. A tidal force results from the unequal gravitational pull on two sides of a body. In a complex kind of modern dance, the large moons of Jupiter are caught in the varying gravity grip of both the giant planet and each other. This leads to gravitational flexing or kneading i... |
these long lines are single, but most are double or multiple, looking rather like the remnants of a colossal freeway system. Figure 12.5. Evidence for an Ocean on Europa. (a) A close-up of an area called Conamara Chaos is shown here with enhanced color. This view is 70 kilometers wide in its long dimension. It appears... |
Europa looks just as we would expect for a thick layer of ice that was broken up into giant icebergs and ice floes and then refrozen in place. When the ice breaks, water or slush from below may be able to seep up through the cracks and make the ridges and multiple-line features we observe. Many episodes of ice crackin... |
of our Moon, with nearly the same size and density. We might therefore expect it to have experienced a similar history. Its appearance, as photographed from space, tells us another story, however (Figure 12.7). Instead of being a dead cratered world, Io turns out to have the highest level of volcanism in the solar sys... |
dioxide. When these icy deposits are suddenly heated, the result is great eruptive plumes far larger than any ejected from terrestrial volcanoes. As the rising plumes cool, the sulfur and sulfur dioxide recondense as solid particles that fall back to the surface in colorful “snowfalls” that extend as much as a thousan... |
col11992/1.8 Chapter 12 Rings, Moons, and Pluto 417 Figure 12.10. Lava Fountains on Io. Galileo captured a number of eruptions along the chain of huge volcanic calderas (or pits) on Io called Tvashtar Catena in this false-color image combining infrared and visible light. The bright orange-yellow areas at left are place... |
e, and Callisto at the same resolution. Note that the number of craters (and thus the age of the surface we see) increases as we go from Europa to Ganymede to Callisto. The Europa image is one of those where the system of cracks and ridges resembles a freeway system. (credit: modification of work by NASA/JPL/DLR) 12.3 ... |
as hydrogen cyanide (HCN), cyanogen (C2N2), and cyanoacetylene (HC3N). Their presence indicates an active chemistry in This OpenStax book is available for free at http://cnx.org/content/col11992/1.8 Chapter 12 Rings, Moons, and Pluto 419 which sunlight interacts with atmospheric nitrogen and methane to create a rich m... |
more than an hour before the probe succumbed to the frigid temperature. 420 Chapter 12 Rings, Moons, and Pluto Figure 12.13. Views of the Surface of Titan. The left image shows the views of Titan from the descent camera, in a flattened projection, at different altitudes. The right image, taken after landing, shows a b... |
by NASA/JPL/ ESA/University of Arizona) These discoveries raise the question of whether there could be life on Titan. Hydrocarbons are fundamental for the formation of the large carbon molecules that are essential to life on our planet. However, the temperature on Titan is far too low for liquid water or for many of t... |
reveals a long history of geological evolution (Figure 12.15). Although some impact craters are found, many regions have been flooded fairly recently by the local version of “lava” (perhaps water or water-ammonia mixtures). There are also mysterious regions of jumbled or mountainous terrain. Figure 12.15. Neptune’s Mo... |
surface deduced from the New Horizons images Note some distinguishing characteristics of Pluto’s large moon Charon Pluto is not a moon, but we discuss it here because its size and composition are similar to many moons in the outer solar system. Our understanding of Pluto (and its large moon Charon) have changed dramat... |
’t put an arrow next to it, though, you probably would never have spotted the dot that moved. (credit: modification of work by the Lowell Observatory Archives) Although the discovery of Pluto appeared initially to be a vindication of gravitational theory similar to the earlier triumph of Adams and Le Verrier in predict... |
s, astronomers began to discover additional small objects in the far outer solar system, showing that Pluto was not unique. We will discuss these trans-neptunian objects later with other small bodies, in the chapter on Comets and Asteroids: Debris of the Solar System. One of them (called Eris) is nearly the same size a... |
his family farm in 1928 with a 9-inch telescope he built. (b) Here Tombaugh is looking through an eyepiece at the Lowell Observatory. (credit b: modification of work by NASA) In 1928, after a hailstorm ruined the crop, Tombaugh decided he needed a job to help support his family. Although he had only a high school educ... |
the astronomy department. He died in 1997; some of his ashes were placed inside the New Horizons spacecraft to Pluto Here is a touching video (https://openstax.org/l/30Tbaugh) about Tombaugh’s life as described by his children. The Nature of Pluto Using data from the New Horizons probe, astronomers have measured the d... |
was still the problem of getting to Pluto, nearly 5 billion kilometers from Earth, without waiting decades. The answer was to use Jupiter’s gravity to slingshot the spacecraft toward Pluto. The 2006 launch of New Horizons started the mission with a high speed, and the Jupiter flyby just a year later gave it the requir... |
University Applied Physics Laboratory/Southwest Research Institute) Figure 12.22 shows some of the remarkable variety of surface features New Horizons revealed. At the right of this image we see the “shoreline” of the vast bowl of nitrogen ice we saw as the smooth region in Figure 12.21. Temporarily nicknamed the “Spu... |
Figure 12.23. Diversity of Terrains on Pluto. (a) In this photo, about 250 kilometers across, we can see many different kinds of terrain. At the bottom are older, cratered highlands; a V-shaped region of hills without cratering points toward the bottom of the image. Surrounding the Vshaped dark region is the smooth, b... |
scattered craters in the lower part of the image, but much of the rest of the surface appears smooth. Crossing the center of the image is a belt of rough terrain, including what appear to be tectonic valleys, as if some forces had tried to split Charon apart. Topping off this strange image is a distinctly red polar ca... |
own orbit around the planet. Thus, the inner particles revolve faster than those farther out, and the ring as a whole does not rotate as a solid body. In fact, it is better not to think of a ring rotating at all, but rather to consider the revolution (or motion in orbit) of its individual moonlets. If the ring particl... |
antic names of A, B, and C Rings. Table 12.3 gives the dimensions of the rings in both kilometers and units of the radius of Saturn, RSaturn. The B Ring is the brightest and has the most closely packed particles, whereas the A and C Rings are translucent. The total mass of the B Ring, which is probably close to the mas... |
92/1.8 Chapter 12 Rings, Moons, and Pluto 435 Figure 12.27. Artist’s Idealized Impression of the Rings of Saturn as Seen from the Inside. Note that the rings are mostly made of pieces of water ice of different sizes. At the end of its mission, the Cassini spacecraft is planning to cut through one of the gaps in Saturn’... |
region (lower part of image). These dark stripes (shown here in exaggerated color) have elevated temperatures and are the source of the many geysers discovered on Enceladus. They are about 130 kilometers long and 40 kilometers apart. (b) Here Enceladus is shown to scale with Great Britain and the coast of Western Euro... |
another an occultation. During the 1977 occultation, astronomers expected the star’s light to disappear as the planet moved across it. But in addition, the star dimmed briefly several times before Uranus reached it, as each narrow ring passed between the star and the telescope. Thus, the rings were mapped out in detai... |
is available for free at http://cnx.org/content/col11992/1.8 Chapter 12 Rings, Moons, and Pluto 439 Figure 12.31. Rings of Neptune. This long exposure of Neptune’s rings was photographed by Voyager 2. Note the two denser regions of the outer ring. (credit: modification of work by NASA/JPL Mark Showalter (of the SETI I... |
linear diameter distance we get 5 arcsec 206,265 arcsec = 20 km distance. So, the distance is about 825,000 km. Interactions between Rings and Moons Much of our fascination with planetary rings is a result of their intricate structures, most of which owe their existence to the gravitational effect of moons, without wh... |
OpenStax book is available for free at http://cnx.org/content/col11992/1.8 Chapter 12 Rings, Moons, and Pluto 441 As we have seen, the largest features in the rings of Saturn are produced by gravitational resonances with the inner moons, while much of the fine structure is caused by smaller embedded moons. In the case... |
to the solar system? In the case of the main rings of Saturn, their mass is about the same as that of the inner moon 442 Chapter 12 Rings, Moons, and Pluto Mimas. Thus, they could have been formed by the break-up of a Mimas-sized moon, perhaps very early in solar system history, when there were many interplanetary pro... |
cycle on Earth (but with liquid methane and ethane). The Cassini-Huygens lander set down on Titan and showed a scene with boulders, made of water ice, frozen harder than rock. Neptune’s cold moon Triton has a very thin atmosphere and nitrogen gas geysers. 12.4 Pluto and Charon Pluto and Charon have been revealed by th... |
�The Strangest Satellites in the Solar System.” Scientific American (August 2006): 40. Small irregular moons in the outer solar system. Lakdawalla, E. “Ice Worlds of the Ringed Planet.” Sky & Telescope (June 2009): 27. On the Cassini mission exploration of Enceladus, Iapetus, and other moons. Mackenzie, D. “Is There Li... |
Sky & Telescope (May 2013): 18. Good 7-page summary of what we know. This OpenStax book is available for free at http://cnx.org/content/col11992/1.8 Chapter 12 Rings, Moons, and Pluto 445 Burns, J., et al. “Bejeweled Worlds.” Scientific American (February 2002): 64. On rings throughout the solar system. Elliot, J., et... |
app/ju[iter-atlas/id352033947?mt=8 • Saturn Atlas: https://itunes.apple.com/us/app/saturn-atlas/id352038051?mt=8 Videos Amazing Moons: https://www.youtube.com/watch?v=CQjZf2bW9XQ. 2016 NASA video on intriguing moons in our solar system (4:16). Briny Breath of Enceladus: http://www.jpl.nasa.gov/video/details.php?id=846.... |
5zcrEze8L4. 2013 talk by Mark Showalter in the Silicon Valley Astronomy Lecture Series (1:30:59). COLLABORATIVE GROUP ACTIVITIES A. Imagine it’s the distant future and humans can now travel easily among the planets. Your group is a travel agency, with the task of designing a really challenging tour of the Galilean moon... |
prepared to deal with? Who should be in charge of making such decisions? E. In the same spirit as Activity D, your group may want to watch the 2013 science fiction film Europa Report. The producers tried to include good science in depicting what it would be like for astronauts to visit that jovian moon. How well does ... |
your group feel about Pluto’s new classification? (After you have discussed it within the group, you may want to watch The Great Planet Debate video recommended in “For Further Exploration.”) EXERCISES Review Questions 1. What are the moons of the outer planets made of, and how is their composition different from that... |
are black? 19. Suppose you miraculously removed all of Saturn’s moons. What would happen to its rings? 20. We have a lot of good images of the large moons of Jupiter and Saturn from the Galileo and Cassini spacecraft missions (check out NASA’s Planetary Photojournal site, at http://photojournal.jpl.nasa.gov, to see th... |
s long blue ion tail and the shorter white dust tail. You will learn about these two types of comet tails, and how they form, in this chapter. (credit: modification of work by ESO/E. Slawik) Chapter Outline 13.1 Asteroids 13.2 Asteroids and Planetary Defense 13.3 The “Long-Haired” Comets 13.4 The Origin and Fate of Com... |
(or as it was later called, “minor planet”) orbiting at 2.8 AU from the Sun. His discovery, which he named Ceres, was quickly followed by the detection of three other little planets in similar orbits. Clearly, there was not a single missing planet between Mars and Jupiter but rather a whole group of objects, each much... |
free at http://cnx.org/content/col11992/1.8 Chapter 13 Comets and Asteroids: Debris of the Solar System 451 The Minor Planet Center (https://openstaxcollege.org/l/30minplancen) is a worldwide repository of data on asteroids. Visit it online to find out about the latest discoveries related to the small bodies in our so... |
without a collision.) Figure 13.2. Asteroids in the Solar System. This computer-generated diagram shows the positions of the asteroids known in 2006. If the asteroid sizes were drawn to scale, none of the dots representing an asteroid would be visible. Here, the asteroid dots are too big and give a false impression of... |
about their composition. The dark asteroids are revealed from spectral studies to be primitive bodies (those that have changed little chemically since the beginning of the solar system) composed of silicates mixed with dark, organic carbon compounds. These are known as C-type asteroids (“C” for carbonaceous). Two of t... |
Where Different Types of Asteroids Are Found. Asteroids of different composition are distributed at different distances from the Sun. The S-type and C-type are both primitive; the M-type consists of cores of differentiated parent bodies. Vesta: A Differentiated Asteroid Vesta is one of the most interesting of the aste... |
printed to the same scale. Gaspra and Ida are S-type and were investigated by the Galileo spacecraft; Mathilde is C-type and was a flyby target for the NEAR-Shoemaker spacecraft. (credit: modification of work by NEAR Project, Galileo Project, NASA) The detailed images allowed us to count the craters on Gaspra and Ida,... |
other smaller asteroids. Their largest dimensions are about 26 kilometers and 16 kilometers, respectively. The small outer moons of Jupiter and Saturn were probably also captured from passing asteroids, perhaps early in the history of the solar system. Figure 13.7. Moons of Mars. The two small moons of Mars, (a) Phobo... |
the surface rubble layer is 100 meters deep. The top of loose soil is dotted with scattered, half-buried boulders. There are so many of these boulders that they are more numerous than the craters. Of course, with the gravity so low on this small world, a visiting astronaut would find loose boulders rolling toward her ... |
entry. The return capsule, which separated from the main spacecraft and parachuted to the surface, glows at the bottom right. (credit: modification of work by NASA Ames/Jesse Carpenter/Greg Merkes) The most ambitious asteroid space mission (called Dawn) has visited the two largest main belt asteroids, Ceres and Vesta, ... |
13 Comets and Asteroids: Debris of the Solar System The space agencies involved with the Dawn mission have produced nice animated “flyover” videos of Vesta (https://openstaxcollege.org/l/30vestaflyover) and Ceres (https://openstaxcollege.org/l/ 30ceresflyover) available online. 13.2 ASTEROIDS AND PLANETARY DEFENSE Lea... |
area directly affected, on the Tunguska River in Siberia, was unpopulated, and no one was killed. However, the area of forest destroyed by the blast was large equal to the size of a major city (Figure 13.13). Together with any comets that come close to our planet, such asteroids are known collectively as near-Earth ob... |
our civilization. The Spaceguard goal of 90% was reached in 2012 when nearly a thousand of these 1-kilometer near-Earth asteroids (NEAs) had been found, along with more than 10,000 smaller asteroids. Figure 13.14 shows how the pace of NEA discoveries has been increasing over recent years. 462 Chapter 13 Comets and Ast... |
are not yet tracking, we will have about a 5-second warning that one is going to hit Earth—in other words, we won’t see it until it enters the atmosphere. Clearly, this estimate gives us a lot of motivation to continue these surveys to track as many asteroids as possible. Though entirely predictable over times of a fe... |
it would miss Earth. The most straightforward way to deflect it would be to crash a spacecraft into it, either slowing it or speeding it up, slightly changing its orbital period. If this were done several years before the predicted collision, the asteroid would miss the planet entirely—making an asteroid impact the on... |
s have been observed from the earliest times: accounts of comets are found in the histories of virtually all ancient civilizations. The typical comet, however, is not spectacular in our skies, instead having the appearance of a rather faint, diffuse spot of light somewhat smaller than the Moon and many times less brill... |
historical records that Comet Halley has actually been observed and recorded on every passage near the Sun since 239 BCE at intervals ranging from 74 to 79 years. The period of its return varies somewhat because of orbital changes produced by the pull of the giant planets. In 1910, Earth was brushed by the comet’s tai... |
be variable, and discussed the nature and size of nebulae (glowing cloudlike structures visible in telescopes). While in Saint Helena, Halley observed the planet 466 Chapter 13 Comets and Asteroids: Debris of the Solar System Mercury going across the face of the Sun and developed the mathematics of how such transits c... |
in urban areas (see the image that opens this chapter, Figure 13.1). Table 13.2 lists some well-known comets whose history or appearance is of special interest. This OpenStax book is available for free at http://cnx.org/content/col11992/1.8 Chapter 13 Comets and Asteroids: Debris of the Solar System 467 Some Interesti... |
Whipple in 1950. Before Whipple’s work, many astronomers thought that a comet’s nucleus might be a loose aggregation of solids, sort of an orbiting “gravel bank,” Whipple proposed instead that the nucleus is a solid object a few kilometers across, composed in substantial part of water ice (but with other ices as well)... |
was obtained by the ESA Giotto spacecraft from a distance of about 1000 kilometers. The bright areas are jets of material escaping from the surface. The length of the nucleus is 10 kilometers, and details as small as 1 kilometer can be made out. (credit: modification of work by ESA) The Comet’s Atmosphere The spectacu... |
the comet’s orbit. Newton proposed that comet tails are formed by a repulsive force of sunlight driving particles away from the head—an idea close to our modern view. Figure 13.22. Comet Orbit and Tail. The orientation of a typical comet tail changes as the comet passes perihelion. Approaching the Sun, the tail is beh... |
streaking toward the Sun, one of almost 3000 such sightings. You can also watch a brief video by NASA entitled “Why Are We Seeing So Many Sungrazing Comets?” The Rosetta Comet Mission In the 1990s, European scientists decided to design a much more ambitious mission that would match orbits with an incoming comet and fo... |
in September 2015, the spacecraft backed off to ensure its safety. The extent of the Rosetta images (and data from other instruments) far exceeds anything astronomers had seen before from a comet. The best imaging resolution was nearly a factor of 100 greater than in the best Halley images. At this scale, the comet ap... |
from the water found on Earth. Thus, apparently comets like 67P did not contribute to the origin of our oceans or the water in our bodies, as some scientists had thought. This OpenStax book is available for free at http://cnx.org/content/col11992/1.8 Chapter 13 Comets and Asteroids: Debris of the Solar System 473 Figu... |
to the 474 Chapter 13 Comets and Asteroids: Debris of the Solar System Sun out to almost the distance of Uranus (Figure 13.26). The diameter of Chiron is estimated to be about 200 kilometers, much larger than any known comet. Figure 13.26. Chiron’s Orbit. Chiron orbits the Sun every 50 years, with its closest approach... |
AU from the Sun. This OpenStax book is available for free at http://cnx.org/content/col11992/1.8 Chapter 13 Comets and Asteroids: Debris of the Solar System 475 The short-period comets (such as Halley) are thought to originate in the Kuiper belt, where small gravitational perturbations from Neptune can gradually shift... |
the Oort cloud. In addition, we estimate that about 10 times this number of icy objects could be orbiting the Sun in the volume of space between the Kuiper belt (which is gravitationally linked to Neptune) and the Oort cloud. These objects remain undiscovered because they are too faint to be seen directly and their or... |
� × 3 m3 ≈ 1015 kg = 1012 tons To calculate the total mass of the cloud, we multiply this typical mass for one comet by the number of comets: Check Your Learning total mass = 1015 kg/comet × 1012 comets = 1027 kg How does the total mass we calculated above compare to the mass of Jupiter? To the mass of the Sun? (Give a... |
imals caused the orbit of Jupiter to drift inward, whereas the orbits of Saturn, Uranus, and Neptune all expanded, carrying the Kuiper belt with them. Another hypotheses involves a fifth giant planet that was expelled from the solar system entirely as the planetary orbits shifted. Neptune’s retrograde (backward-orbitin... |
s of cosmic gas and dust) and galaxies (distant groupings of stars). Next, they must check that they have not come across a comet that is already known, in which case, they will only get a pat on the back instead of fame and glory. Then they must re-observe or re-image it sometime later to see whether its motion in the... |
that comes within the gravitational influence of a planet has three possible fates. It can (1) impact the planet, ending the story at once; (2) speed up and be ejected, leaving the solar system forever; or (3) be perturbed into an orbit with a shorter period. In the last case, its fate is sealed. Each time it approach... |
owed brilliantly for about 15 minutes, a glow we could detect with infrared-sensitive telescopes. 480 Chapter 13 Comets and Asteroids: Debris of the Solar System Figure 13.30. Comet Impact on Jupiter. (a) The “string” of white objects are fragments of Comet Shoemaker-Levy 9 approaching Jupiter. (b) The first fragment o... |
, the winds on Jupiter blended these features into a broad spot that remained visible for more than a month. (credit: modification of work by H. Hammel, MIT, and NASA/ESA) For comets that do not meet so dramatic an end, measurements of the amount of gas and dust in their atmospheres permit us to estimate the total loss... |
curved stream; the ion tail is a stream of ionized particles evaporated from a comet and then swept away from the Sun by the solar wind SUMMARY 13.1 Asteroids The solar system includes many objects that are much smaller than the planets and their larger moons. The rocky ones are generally called asteroids. Ceres is th... |
in diameter and composed of volatiles (primarily frozen H2O) and solids (including both silicates and carbonaceous materials). Whipple first suggested this “dirty snowball” model in 1950; it has been confirmed by spacecraft studies of several comets. As the nucleus approaches the Sun, its volatiles evaporate (perhaps ... |
44. Nice overview. Boslaugh, M. “In Search of Death-Plunge Asteroids.” Astronomy (July 2015): 28. On existing and proposed programs to search for Earth-crossing asteroids. Cooke, B. “Fatal Attraction.” Astronomy (May 2006): 46. On near-Earth asteroid Apophis, its orbit, and what we can learn from it. Durda, D. “Odd Co... |
Comet Science.” Sky & Telescope (December. 2013): 18. Nice summary of what we know about comets and questions we have. Rao, J. “How Often do Bright Comets Appear?” Sky & Telescope (November 2013): 30. Nice summary of bright comets in the last century and what factors make a comet spectacular in our skies. Sekanina, Z.... |
://stardust.jpl.nasa.gov/home/index.html. Learn about this mission to collect a sample of a comet and bring it back to Earth. Videos Asteroids Sweating the Small Stuff: The Fear and Fun of Near-Earth Asteroids: https://www.youtube.com/ watch?v=5gyAvc5OhII. Harvard Observatory Night Lecture by Jose-Luis Galache (1:18:07... |
that mining asteroids may be a way to get needed resources in the future. Make a list of materials in asteroids (and comets that come to the inner solar system) that may be valuable to a space-faring civilization. What are the pros and cons of undertaking mining operations on these small worlds? D. As discussed in the... |
. Vesta is unusual as it contains what mineral on its surface? What does the presence of this material indicate? 6. Compare asteroids of the asteroid belt with Earth-approaching asteroids. What is the main difference between the two groups? 7. Briefly describe NASA’s Spaceguard Survey. How many objects have been found ... |
extra bonus, can you find any images of such features on a moon like Callisto? You can use an online site of planetary images, such as the Planetary Photojournal, at photojournal.jpl.nasa.gov.) 20. Why have we found so many objects in the Kuiper belt in the last two decades and not before then? 21. Why is it hard to g... |
the largest 13 objects and compare it to the mass of the main asteroid belt. 28. What is the period of revolution about the Sun for an asteroid with a semi-major axis of 3 AU in the middle of the asteroid belt? 29. What is the period of revolution for a comet with aphelion at 5 AU and perihelion at the orbit of Earth?... |
Objectives By the end of this section, you will be able to: Explain what a meteor is and why it is visible in the night sky Describe the origins of meteor showers As we saw in Comets and Asteroids: Debris of the Solar System, the ices in comets evaporate when they get close to the Sun, together spraying millions of to... |
Earth’s atmosphere is estimated to be about 100 tons per day (which seems like a lot if you imagine it all falling in one place, but remember it is spread out all over our planet’s surface). This OpenStax book is available for free at http://cnx.org/content/col11992/1.8 Chapter 14 Cosmic Samples and the Origin of the ... |
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