Astronomy Test 2 Test Questions – Flashcards
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Which of the following is not a major pattern of motion in the solar system?
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Nearly all comets orbit the Sun in same direction and roughly the same plane
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Which of the following is not a major difference between the terrestrial and jovian planets in our solar system?
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Terrestrial planets contain large quantities of ice and jovian planets do not.
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Consider the following statement: "Rocky asteroids are found primarily in the asteroid belt and Kuiper belt while icy comets are found primarily in the Oort cloud." What's wrong with this statement?
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The Kuiper belt contains icy comets, not rocky asteroids.
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Which of the following is not a real difference between asteroids and comets?
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Asteroids orbit the Sun while comets just float randomly around in the Oort cloud.
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The following statements are all true. Which one counts as an "exception to the rule" in being unusual for our solar system?
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The diameter of Earth's Moon is about 1/4 that of Earth.
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Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is ______.
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much larger
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Einstein's famous equation, E=mc 2, explains the fact that __________.
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the Sun generates energy to shine by losing some 4 million tons of mass each second
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Venus has a higher average surface temperature than Mercury. Why?
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Because its surface is heated by an extreme greenhouse effect.
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In what way is Venus most similar to Earth?
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Both planets are nearly the same size.
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Which of the following statements about the recently-discovered object Eris is not true?
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It is thought to be the first example of a new class of object.
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Mars has two moons that are most similar in character to:
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small asteroids
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Imagine that an alien spaceship crashed onto Earth. Which statement would most likely be true?
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It would crash in the ocean.
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Which planet listed below has the most extreme seasons?
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uranus
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In what way is Pluto more like a comet than a planet?
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It is made mostly of rock and ice.
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Why was it advantageous for the Voyager mission to consist of flybys rather than orbiters?
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Each individual spacecraft was able to visit more than one planet.
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Why has NASA sent recent orbiters to Mars (such as Mars Reconnaissance Orbiter) on trajectories that required them to skim through Mars's atmosphere before settling into their final orbits?
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It saves money because the spacecraft uses atmospheric drag to slow down rather than needing to carry enough fuel to slow by firing rocket engines.
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Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true?
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All the planets orbit counterclockwise around the Sun.
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The terrestrial planets in our solar system are:
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Mercury, Venus, Earth, and Mars.
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The jovian planets in our solar system are:
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Jupiter, Saturn, Uranus, and Neptune.
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When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all the following chemicals except ______.
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carbon dioxide
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Which of the following statements about the asteroid belt is not true?
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The combined mass of all the asteroids is roughly the same as the mass of the Earth.
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What is the Kuiper belt?
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A region of the solar system beginning just beyond the orbit of Neptune that contains many icy comets.
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What is the Oort cloud?
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It's not really a cloud at all, but rather refers to the trillion or so comets thought to orbit the Sun at great distances.
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Which of the following statements about our Sun is not true?
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The Sun's diameter is about 5 times that of Earth.
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Which of the following is not true of Mercury?
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It has been studied closely by several NASA spacecraft.
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Which of the following statements about Mars is not true?
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We could survive on Mars without spacesuits, as long as we brought oxygen in scuba tanks.
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The planet in our solar system with the highest average surface temperature is:
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venus
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Which jovian planet does not have rings?
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All the jovian planets have rings
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Which moons are sometimes called the Galilean moons?
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The four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto.
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Which of the following statements about Pluto is not true?
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It is the largest known object that is considered to be a dwarf planet.
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The Cassini mission to Saturn consists of:
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An orbiter that orbits Saturn and a probe that descended to the surface of Titan.
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Which planet (besides Earth) has been visited by the largest number of robotic spacecraft?
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Mars
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Which of the following best explains why we can rule out the idea that planets are usually formed by near-collisions between stars?
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Stellar near-collisions are far too rare to explain all the planets now known to orbit nearby stars.
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According to our modern science, which of the following best explains why the vast majority of the mass of our solar system consists of hydrogen and helium gas?
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Hydrogen and helium are the most common elements throughout the universe, because they were the only elements present when the universe was young.
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According to our theory of solar system formation, which law best explains why the central regions of the solar nebula got hotter as the nebula shrank in size?
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The law of conservation of energy
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According to our theory of solar system formation, which law best explains why the solar nebula spun faster as it shrank in size?
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The law of conservation of angular momentum
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According to our present theory of solar system formation, which of the following best explains why the solar nebula ended up with a disk shape as it collapsed?
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It flattened as a natural consequence of collisions between particles in the nebula.
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What is the primary basis upon which we divide the ingredients of the solar nebula into four categories (hydrogen/helium; hydrogen compound; rock; metal)?
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The temperatures at which various materials will condense from gaseous form to solid form.
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According to our present theory of solar system formation, which of the following statements about the growth of terrestrial and jovian planets is not true?
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The jovian planets began from planetesimals made only of ice, while the terrestrial planets began from planetesimals made only of rock and metal.
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Many meteorites appear to have formed very early in the solar system's history. How do these meteorites support our theory about how the terrestrial planets formed?
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The meteorites appearance and composition is just what we'd expect if metal and rock condensed and accreted as our theory suggests.
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According to present understanding, which of the following statements about the solar wind is not true?
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It is even stronger today than it was when the Sun was young.
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According to our present theory of solar system formation, how did Earth end up with enough water to make oceans?
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The water was brought to the forming Earth by planetesimals that accreted beyond the orbit of Mars.
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According to our present theory of solar system formation, which of the following objects now reside quite far from the place where they formed originally?
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Oort cloud comets
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What is the primary reason that astronomers suspect that some jovian moons were captured into their current orbits?
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Some moons have orbits that are "backwards" (compared to their planet's rotation) or highly inclined to their planet's equator.
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Which of the following is not a line of evidence supporting the hypothesis that our Moon formed as a result of a giant impact?
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The Pacific Ocean appears to be a large crater - probably the one made by the giant impact.
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Why are terrestrial planets denser than jovian planets?
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Only dense materials could condense in the inner solar nebula.
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Suppose you find a rock that contains 10 micrograms of radioactive potassium-40, which has a half-life of 1.25 billion years. By measuring the amount of its decay product (argon-40) present in the rock, you conclude that there must have been 80 micrograms of potassium-40 when the rock solidified. How old is the rock?
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The current 10 micrograms of potassium-40 is 1/8 of the original 80 grams, which means the amount of potassium-40 has declined by a factor of 8. Therefore, three half-lives have passed (since 23 = 8) and the rock is 3x1.25 = 3.75 billion years old.
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How do scientists determine the age of the solar system?
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Radiometric dating of meteorites
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The region of our solar system between Mercury and Mars has very few asteroids, while the region between Mars and Jupiter has many asteroids. Based on what you have learned, what is the most likely explanation for the lack of asteroids between Mercury and Mars?
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There were very few planetary leftovers in this region, because most of the solid material was accreted by the terrestrial planets as the planets formed.
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About 2% of our solar nebula consisted of elements besides hydrogen and helium. However, the very first generation of star systems in the universe probably consisted only of hydrogen and helium. Which of the following statements is most likely to have been true about these first-generation star systems?
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There were no comets or asteroids in these first-generation star systems.
