Name: ______Class: ______Date: ______ID: A

HW9 (106 points possible)

True/False (2 points each) Indicate whether the statement is true or false.

____ 1. The of Mars is mostly composed of carbon dioxide; therefore the greenhouse effect makes the average temperature 35 degrees warmer than it would be without its atmosphere.

____ 2. In the absence of a greenhouse effect, water on the surface of would be frozen.

____ 3. Aurorae are produced only near the northern and southern magnetic poles of a because charged particles arriving in the solar wind cannot cross the magnetic field lines.

____ 4. Winds are generated on Earth primarily because the Sun unevenly heats our rotating planet.

____ 5. ’s atmospheric clouds are so thick that the surface of the planet is not seen when observing it in visible light.

Multiple Choice (4 points each) Identify the choice that best completes the statement or answers the question.

____ 1. Which is NOT a reason that we suspect that the extinction of the dinosaurs was caused by a large impact by a large object? a. Many dinosaur fossils are found below the K-T boundary, but none above it. b. The material in the K-T boundary is rich in iridium. c. Soot is found in the material in the K-T boundary, which probably came from fires caused by the impact. d. An impact crater has been found near Mexico’s Yucatan Peninsula. e. The remaining meteorite has been identified on the bottom of the Gulf of Mexico. ____ 2. What is the reason Mercury has so little gas in its atmosphere? a. Its mass is small. d. Its escape velocity is low. b. It has a high temperature. e. All of the above are reasons. c. It is close to the Sun.

____ 3. Why did the terrestrial lose the majority of the gas in their primary ? a. They were too hot and their escape velocities too low to hold onto them. b. The solar wind was too strong and blew these gasses off the planets. c. Their high surface temperatures made the gas chemically react with the rock. d. The centrifugal force from the planets’ fast rotation rates made them fly off. e. The initial gases were so heavy when the planet differentiated that they sank to the core.

1 Name: ______ID: A

____ 4. The nitrogen in the Earth’s atmosphere primarily came from: a. ammonia delivered by comet impacts b. photosynthesis done by algae and plants c. oxidation of silicate rich minerals d. rock delivered by asteroid impacts e. its primary atmosphere

____ 5. Earth has roughly ______times more atmospheric pressure than Mars and ______times less than Venus. a. 10; 10 d. 2; 10 b. 200; 100 e. 1,000; 200 c. 2,000; 2

____ 6. The main greenhouse gases in the atmosphere of the terrestrial planets are: a. oxygen and nitrogen d. hydrogen and helium b. methane and ozone e. methane and ammonia c. carbon dioxide and water vapor

____ 7. Earth releases the energy it receives from the Sun by emitting ______radiation. a. infrared d. radio b. visible e. microwave c. ultraviolet

____ 8. The greenhouse effect raises Earth’s surface temperature by roughly: a. 0 K d. 35 K b. 0.35 K e. 350 K c. 3.5 K

____ 9. If photosynthesis were to disappear on Earth: a. the atmosphere would become less dense b. oxygen would disappear from the atmosphere c. the atmosphere would become hotter d. nitrogen would disappear from the atmosphere e. the amount of water vapor in the atmosphere would decrease

____ 10. Approximately ______years ago, ______began producing oxygen in enough amounts to be a significant fraction in the Earth’s atmosphere. a. 100 million; trees and plants d. 2.5 billion; bacteria and algae b. 1 billion; trees and plants e. 2,000; animals and humans c. 250 million; bacteria and algae

____ 11. The shape of the Earth’s magnetosphere is modified by: a. the Moon’s tidal force d. asymmetries in the shape of Earth’s core b. the solar wind e. Earth’s elliptical orbit c. Earth’s own gravity

2 Name: ______ID: A

____ 12. Hurricanes are powered by: a. Hadley circulation d. electrical conductivity of water b. the Coriolis effect e. the greenhouse effect c. the heat of vaporization of water

____ 13. Earth’s sky is blue because: a. blue light from the sun is more readily scattered by molecules in the atmosphere than red light b. of reflected light from the oceans c. red light from the sun is more readily scattered by molecules in the atmosphere than blue light d. molecules that make up the Earth’s atmosphere radiate preferentially at blue wavelengths e. the Sun radiates more blue light than other wavelengths

____ 14. Venus has an unusual rotation rate because: a. it is very slow d. it is very fast b. it is very slow and retrograde e. it is very fast and retrograde c. its obliquity is 90 degrees

Short Answer (8 points each)

1. If there is water on Mars today, where is it likely to be? Name two separate pieces of evidence we have that Mars once had flowing water on its surface and how this evidence was obtained.

2. Where is most of Earth’s supply of carbon dioxide today?

3. If there are 104 kg of air above every square meter of the surface of Earth, and Earth is modeled as a sphere of radius 6.4 × 106 m, what is the mass of Earth’s atmosphere and what fraction is it of the total mass of the Earth? Show your calculation.

4. Over the last century, why has the ozone hole over the Earth grown larger? How long might it take to revert to its former state?

5. The global winds on Earth are the result of a combination of what three things?

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