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Astronomy Midterm
Question | Answer |
---|---|
Which of the following is not a major pattern of motion in the solar system? | Nearly all comets orbit the Sun in same direction and roughly the same plane |
Which of the following is not a major difference between the terrestrial and jovian planets in our solar system? | Terrestrial planets contain large quantities of ice and jovian planets do not. |
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? | The Kuiper belt contains icy comets, not rocky asteroids. |
Which of the following is not a real difference between asteroids and comets? | Asteroids orbit the Sun while comets just float randomly around in the Oort cloud. |
The following statements are all true. Which one counts as an "exception to the rule" in being unusual for our solar system? | The diameter of Earth's Moon is about 1/4 that of Earth. |
Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is ______. | much larger |
Einstein's famous equation, E | mc 2, explains the fact that __________. |
Venus has a higher average surface temperature than Mercury. Why? | Because its surface is heated by an extreme greenhouse effect. |
In what way is Venus most similar to Earth? | Both planets are nearly the same size. |
Which of the following statements about the recently-discovered object Eris is not true? | It is thought to be the first example of a new class of object. |
Mars has two moons that are most similar in character to: | small asteroids |
Imagine that an alien spaceship crashed onto Earth. Which statement would most likely be true? | It would crash in the ocean. |
Which planet listed below has the most extreme seasons? | uranus |
In what way is Pluto more like a comet than a planet? | It is made mostly of rock and ice. |
Why was it advantageous for the Voyager mission to consist of flybys rather than orbiters? | Each individual spacecraft was able to visit more than one planet. |
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? | 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. |
Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true? | All the planets orbit counterclockwise around the Sun. |
The terrestrial planets in our solar system are: | Mercury, Venus, Earth, and Mars. |
The jovian planets in our solar system are: | Jupiter, Saturn, Uranus, and Neptune. |
When we say that jovian planets contain significant amounts of hydrogen compounds, we mean all the following chemicals except ______. | carbon dioxide |
Which of the following statements about the asteroid belt is not true? | The combined mass of all the asteroids is roughly the same as the mass of the Earth. |
What is the Kuiper belt? | A region of the solar system beginning just beyond the orbit of Neptune that contains many icy comets. |
What is the Oort cloud? | 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. |
Which of the following statements about our Sun is not true? | The Sun's diameter is about 5 times that of Earth. |
Which of the following is not true of Mercury? | It has been studied closely by several NASA spacecraft. |
Which of the following statements about Mars is not true? | We could survive on Mars without spacesuits, as long as we brought oxygen in scuba tanks. |
The planet in our solar system with the highest average surface temperature is: | venus |
Which jovian planet does not have rings? | All the jovian planets have rings |
Which moons are sometimes called the Galilean moons? | The four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto. |
Which of the following statements about Pluto is not true? | It is the largest known object that is considered to be a dwarf planet. |
The Cassini mission to Saturn consists of: | An orbiter that orbits Saturn and a probe that descended to the surface of Titan. |
Which planet (besides Earth) has been visited by the largest number of robotic spacecraft? | Mars |
Which of the following best explains why we can rule out the idea that planets are usually formed by near-collisions between stars? | Stellar near-collisions are far too rare to explain all the planets now known to orbit nearby stars. |
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? | Hydrogen and helium are the most common elements throughout the universe, because they were the only elements present when the universe was young. |
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? | The law of conservation of energy |
According to our theory of solar system formation, which law best explains why the solar nebula spun faster as it shrank in size? | The law of conservation of angular momentum |
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? | It flattened as a natural consequence of collisions between particles in the nebula. |
What is the primary basis upon which we divide the ingredients of the solar nebula into four categories (hydrogen/helium; hydrogen compound; rock; metal)? | The temperatures at which various materials will condense from gaseous form to solid form. |
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? | The jovian planets began from planetesimals made only of ice, while the terrestrial planets began from planetesimals made only of rock and metal. |
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? | The meteorites appearance and composition is just what we'd expect if metal and rock condensed and accreted as our theory suggests. |
According to present understanding, which of the following statements about the solar wind is not true? | It is even stronger today than it was when the Sun was young. |
According to our present theory of solar system formation, how did Earth end up with enough water to make oceans? | The water was brought to the forming Earth by planetesimals that accreted beyond the orbit of Mars. |
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? | Oort cloud comets |
What is the primary reason that astronomers suspect that some jovian moons were captured into their current orbits? | Some moons have orbits that are "backwards" (compared to their planet's rotation) or highly inclined to their planet's equator. |
Which of the following is not a line of evidence supporting the hypothesis that our Moon formed as a result of a giant impact? | The Pacific Ocean appears to be a large crater - probably the one made by the giant impact. |
Why are terrestrial planets denser than jovian planets? | Only dense materials could condense in the inner solar nebula. |
How do scientists determine the age of the solar system? | Radiometric dating of meteorites |