Awarded Points Points Missed Percentage
32 8 80%
1. Both Venus and Mars have atmospheres which are almost completely composed of carbon dioxide. Why does Venus experience a runaway greenhouse effect while Mars doesn't? A. Venus is bigger than Mars B. Venus has a thick atmosphere, Mars doesn't C. Venus has an ozone layer, Mars doesn't D. Venus is closer to the Sun than Mars While the presence of greenhouse gases is important in the greenhouse effect, it depends on more than just the percentage of atmosphere which is composed of greenhouse gases, but also the total amount of atmosphere. Wrong Correct Answer: B Your Response: D 2. Mercury experiences extreme highs and lows in temperature between day and night because: A. Mercury lacks a blanket of atmosphere. B. The planet's surface is undergoing a runaway greenhouse effect. C. Mercury is so close to the sun. D. Mercury has a low inclination. Without an atmosphere, Mercury has nothing to trap in heat at night, and so it all escapes and the nights are extremely cold, even though it is the closest planet to the Sun. Right Correct Answer: A Your Response: A 3. Which of the following does not have a direct effect on a planet's ability to hold on to a gas? A. distance from the Sun B. surface gravity of the planet C. composition of the gas D. composition of the planet E. temperature of the planet Lighter gases will move faster at a given temperature, and so can escape more easily. Hotter planets will give their gases more energy to escape the gravitational pull of the planet. The
stronger the gravity of a planet, the better it can hold on to the gases. The closer to the Sun a planet it, the hotter its atmosphere (in general). The composition of the planet, though, has no direct effect. Right Correct Answer: D Your Response: D 4. Why is one hemisphere of Mars believed to be older than the other? A. One hemisphere is more heavily cratered. B. One hemisphere is lower. C. One hemisphere leans more away from the Sun. D. One hemisphere is darker. Because one hemisphere is more highly cratered than the other, it must be older, since it had to be around for a longer period of time in order to be hit more often. Right Correct Answer: A Your Response: A 5. Volcanoes on Mars are larger than those on Earth. How do astronomers interpret these observations? A. Earth is older than Mars. B. Mars is older than Earth. C. Tidal interactions are twice as great for Mars since it has two moons. D. Mars is still molten inside its core. E. Crustal plates don't move across the Martian surface. Only Earth exhibits plate tectonics. On other planets, volcanoes never move off of their hot spots, and so just grow bigger and bigger until the planet cools off completely. Right Correct Answer: E Your Response: E 6. How do astronomers know the what entire surface of Venus looks like? A. They've measured changes in the thermal output from the surface in order to map it. B. They've bounced radio signals off of its surface and measured the changes in the returning signal. C. They've been able to observe it with optical telescopes. D. They've sent probes to Venus, which have landed and spend weeks roaming its surface.
Since Venus is covered with a thick cloud coverage, we cannot visual observe the surface of Venus, but radio waves, which are not blocked by clouds, can be bounced off the surface of Venus in order to give us a "picture" of what its surface looks like. Right Correct Answer: B Your Response: B 7. Rank the following terrestrial planets in order of the amount of permanent atmosphere, from least to greatest (1 being least). A. Mars B. Venus C. Earth D. Mercury Mercury, being small and close to the Sun, is unable to hold on to any permanent atmosphere. Mars, at half the size of the Earth, has a limited atmosphere roughly 1/100th the size of Earth's. Venus has the largest atmosphere, roughly 100 times the size of Earth's. Right Correct Answer: A:2, B:4, C:3, D:1 Your Response: A:2, B:4, C:3, D:1 8. Match the terrestrial object with the correct description of its rotation? 1. Mercury 2. Venus 3. Moon 4. Mars A. Its day is only 40 minutes longer than the earth's. B. Its year is shorter, only 225 days, than its slow rotation of 243 days on its axis. C. It always keeps one face tidally locked toward the object around which it revolves. D. Its rotation rate, relative to background stars, is 2/3 as long as its year, due to tidal resonances. Mercury is tidally locked to the Sun, but due to its elliptical orbit, is in a 2:3 resonance. Venus is a very slow rotator, such that it orbits the Sun once before completing a full rotation. The Moon is tidally locked to the Earth in a 1:1 resonance. Mars' rotation is similar to Earth's, only taking 40 minutes longer. Right Correct Answer: A:4, B:2, C:3, D:1 Your Response: A:4, B:2, C:3, D:1
9. Pancake domes, regions where molten rock has bulged out of the ground and then retreated, leaving behind a thin, solid crust, are unique to which planet? A. Mercury B. Earth C. Mars D. Venus Pancake domes are only found on the planet Venus. Right Correct Answer: D Your Response: D 10. The flow patterns found on the surface of Mars suggest A. that Mars is a water-rich world. B. that the climate on Mars was different in the past. C. that volcanism is occurring on Mars. D. that the polar caps are made of water. E. all of the above While liquid water cannot exist on the surface of Mars today, the discovery of flow patterns suggest that it did in the past, when Mars must have been a warmer and wetter planet. Wrong Correct Answer: B Your Response: E