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Astronomy 1010 Exam #2 Chapter
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During the formation of the Solar System, smaller particles in the solar nebula combined to form planetesimals, some of which provided the building blocks for planets. The majority of planetesimals did not become planets, however, and some of them remain in the Solar System today as debris left over from the time of planet formation. Asteroids are a special class of planetesimals that orbit around the Sun. Study the distribution of known asteroids shown in this figure, and choose all of the statements below that match your observations. Choose one or more:
A. The majority of asteroids exist in a region between Jupiter and Mars. B. All of the asteroids exist in a region between Jupiter and Mars. C. Asteroids have been discovered as far out as Pluto.
Based on the figure, which asteroid types would be more common if they were the result of a shattered planet?
Choose one or more: A. M-type B. C-type C. S-type D. All types would be equally common. - ANSWER โโA. M-type C. S-type At least 75% of asteroids are primordial C-type. What does this imply about how the asteroid belt was formed? Choose one: A. It was formed entirely of the pieces of a shattered planet. B. It was formed mostly from pieces of planetesimals that were prevented from getting large enough to differentiate, but it also contains some pieces of objects that were large enough to differentiate and were later shattered. C. It was formed entirely of pieces of planetesimals that were prevented from getting large enough to differentiate, and thus were never part of a planet. D. It was formed mostly from pieces of objects that were large enough to differentiate and were later shattered, but it also contains some planetesimals that were prevented from getting large enough to differentiate. - ANSWER โโB.
large enough to differentiate, but it also contains some pieces of objects that were large enough to differentiate and were later shattered. What determines an asteroid's shape? Choose one: A. All of the asteroids have irregular shapes and are similar in size. B. All of the asteroids have irregular shapes but come in a range of sizes. C. Asteroids have a range of sizes, with the largest being spherical and the smaller ones irregular in shape. D. Asteroids have a range of sizes, with the smallest being spherical and the larger ones irregular in shape. - ANSWER โโC. Asteroids have a range of sizes, with the largest being spherical and the smaller ones irregular in shape. Only larger objects have strong enough self-gravity to force themselves into a spherical shape. The first asteroid discovered, Ceres, is round and was originally classified as a planet. However, it is no longer considered a planet because many other smaller objects were found to exist within its orbit in the asteroid belt. Pluto was discovered later and was classified as a planet. It's larger than Ceres, is
made of ice and rock, and is significantly farther from the Sun than the asteroids. Is it scientifically justifiable to classify Pluto as a planet, but not Ceres? Comparing Pluto to the other planets may answer this.
two distinct types of orbits: short-period and long-period comets.
Watch the following AstroTour animation, and choose the answer below that most likely follows from your observations. Choose one: A. Short-period comets come from some location near the ecliptic plane of the Solar System, and long-period comets come from farther away, with random directions in a spherical distribution around the Sun. B. Short-period comets come from a random direction in a spherical distribution around the Sun, and long-period comets come from farther aw - ANSWER โโA. Short-period comets come from some location near the ecliptic plane of the Solar System, and long-period comets come from farther away, with random directions in a spherical distribution around the Sun. Comets that visit the inner Solar System were kicked there from the Kuiper Belt or Oort Cloud by gravitational close encounters with other objects. Pluto travels through the inner edge of the Kuiper Belt. As Ceres is just a large asteroid, could Pluto be just a large Kuiper Belt comet nucleus?
B. color C. surface temperature D. orbital period E. apparent brightness - ANSWER โโA. composition Due to the mutual synchronous rotation of Pluto and Charon, choose the statement below that best describes what an observer on Pluto would see when looking toward Charon. Choose one: A. The observer would always see the same side of Charon, which would appear to hang motionlessly in the same spot in the sky all the time. B. The observer would always see the same side of Charon, which would make circles around a point in the sky but never rise or set below the horizon. C. The observer would always see the same side of Charon, which would rise and set as it orbits Pluto. D. The observer would see different sides of Charon as it rotates on its axis and would see it rise and set as it orbits Pluto. - ANSWER โโA. The observer would always see the same side of Charon, which would appear to hang
motionlessly in the same spot in the sky all the time. Asteroids are
C. occasionally grow large enough to become differentiated and geologically active. D. have all undergone significant chemical evolution since formation. - ANSWER โโC. occasionally grow large enough to become differentiated and geologically active. Rank these four Solar System bodies in order of their periods, from shortest to longest. - ANSWER โโShortest period Encke Jupiter Saturn Hale-Bopp Longest period Aside from their periods, short- and long-period comets differ because short-period comets Choose one:
A. mostly orbit prograde, while long-period comets have either prograde or retrograde orbits. B. come closer to the Sun at closest approach than long-period comets do. C. contain less ice, while long-period comets contain more. D. do not develop ion tails, while long-period comets do. - ANSWER โโA. mostly orbit prograde, while long-period comets have either prograde or retrograde orbits. A cubic centimeter of the air you breathe contains about 1019 molecules. A comet's tail may typically contain 10 molecules per cubic centimeter. Calculate how large a cube of comet tail material must be on each side in order to contain 1019 molecules. - ANSWER โโ 10 kilometers In 1910, Earth passed through the tail of Comet Halley. Among the various gases in the tail was hydrogen cyanide (HCN), which is deadly to humans. Yet nobody became ill from this event. Why not? Choose one: A. Earth's magnetic field deflects all harmful gases away from the
D. HCN reacts with oxygen in Earth's atmosphere to produce harmless compounds.
- ANSWER โโC. The mass of poisonous gases is tiny compared to the mass of Earth's atmosphere. As a comet leaves the inner Solar System, its ion tail points Choose one: A. forward along the orbit. B. back along the orbit. C. away from the Sun. D. toward the Sun. -ANSWER โโC. away from the Sun. Kuiper Belt objects (KBOs) are actually comet nuclei. Why do they not display comas and tails? Choose one: A. Most of the material has already been stripped from the objects. B. They are too close to the Sun. C. They are too far from the Sun. D. The comas and tails are pointing away from Earth. - ANSWER โโC. They are too far from the Sun.
What are other possible sources of Earth's water?
