Chapter 10

Why does Venus have such a great difference in temperature between its "no atmosphere" temperature and its actual temperature?

It has a large amount of greenhouse gases in its atmosphere.

Which of the following best describes rain on Venus?

It has sulfuric acid rain in its atmosphere, but the drops evaporate before hitting the surface.

Why doesn't Venus have seasons like Mars and Earth do?

Its rotation axis is not tilted.

Why isn't Earth's atmosphere mostly hydrogen?

Light gases such as hydrogen move faster than heavier gases and escape from Earth's gravitational field.

Which of the following planets has the least substantial atmosphere?

Mercury

Which planet experiences the greatest change between its actual day temperature and actual night temperature?

Mercury

Which of the following planets has an exosphere?

Mercury, Venus, Earth, Mars

What is the main reason mountaintops are so cold?

Mountaintops are above much of the greenhouse gas in the atmosphere.

Which of the following gases absorbs ultraviolet light best?

Ozone

Questions from Book

Questions from Book

22. We believe that Venus, Earth, and Mars all started with a significant supply of water. Explain where that water is now for each planet.

The water on Venus, due to its higher temperature became water vapor. This water vapor was broken down into H2 and O2 by the sun's UV light. These lighter molecules were able to escape the atmosphere. The water on Earth, is still mostly present in the oceans of Earth. Earth has enough gravity to hold and atmosphere and is cooler so water remains liquid. The water on Mars was lost to space. Mars having less gravity cannot hold the atmosphere. As the atmosphere was lost, pressure dropped. Water at the lower pressure evaporates and is broken down into H2 and O2 by the Sun's UV light. As the atmosphere thinned the planet got colder and some of the water froze into ice.

The thermosphere is warm because it

absorbs x-rays.

X rays from the Sun's corona

are absorbed in Earth's thermosphere.

Venus has a high albedo because its surface is covered by

clouds.

The proper order of the layers of a generic atmosphere from lowest altitude to highest is

troposphere, stratosphere, thermosphere, exosphere.

The ionosphere is a layer of ionized gas that is

within the thermosphere.

Which of the following factors could explain a gradual warming trend in a planet's climate?

A decreasing albedo.

How is the atmosphere of a planet affected by the rotation rate?

Faster rotation rates produce stronger winds.

Suppose Earth's atmosphere had no greenhouse gases. Then Earth's average surface temperature would be

250 K, which is well below freezing.

Which of the following is not one of the four major factors that can cause a long-term change in a planet's climate?

A change in the strength of the planet's magnetic field.

Earth's stratosphere is heated primarily by which process?

Absorption of ultraviolet radiation by ozone.

1. List several ways that Venus, Earth, and Mars are similar, and several ways they are different.

All 3 are rock and metal, all 3 have atmospheres and iron cores, All 3 have volcanism. They are different, first is size, Mars the smallest. Their atmospheres are very different, Venus dense atmosphere mostly CO2, Mars very thin atmosphere but mostly CO2, Earth medium density atmosphere, primarily N2 and O2. Earth is the only one with liquid water. Earth has plate tectonics, Venus has convection based tectonics, rather than moving plates, Mars does not have tectonics. Earth has heavy erosion from wind and water, Venus almost no erosion (not much wind) and Mars a small amount of erosion from wind but not water.

Why does Mars have more extreme seasons than Earth?

Because it has a more eccentric orbit in addition to its tilt. (It's more ecliptic)

Ch 10 Testbank Questions

Ch 10 Testbank Questions

Which of the following planets has a stratosphere?

Earth

2. Compare the current atmospheres of Earth, Venus, and Mars in terms of composition, thickness (and pressure at the surface), and the greenhouse effect.

Earth is 80% N2 and 20% O2, trace of other gases, pressure of about 1 atmosphere. Water and other greenhouse gases, contribute to warming to keep Earth at a moderate temperature. Venus is 99% CO2 and has a pressure of 90 atmospheres. The density and composition of Venus' atmosphere has led to a runaway greenhouse effect making the temperature very high. Mars has a mostly CO2 atmosphere, but with very low pressure about 1/100 of an atmosphere. There is a small greenhouse effect but not much warming.

What are greenhouse gases?

Gases that absorb infrared light.

How does the greenhouse effect work?

Greenhouse gases transmit visible light, allowing it to heat the surface, but then absorb infrared light from Earth, trapping the heat near the surface.

6. What evidence do we have that there was running (liquid) water on Mars in the past? What evidence is there for water coming out of the ground even today?

Images from Mars Satellite show runoff channels that show evidence of being made by running water. Some dry basins have minerals that only form in water, evidence of lakes. Recent images show streaking in gullies. The streaks grow longer and show evidence of hydrated salts.

Where is most of the water on Mars?

In its polar caps and subsurface ground ice.

24. The runaway greenhouse effect and its inverse, the runaway refrigerator effect, have led to harsh, uninhabitable conditions on Venus and Mars. Does the greenhouse effect always cause climate changes leading to loss of water and life? Give a reason for your answer.

The greenhouse effect does not always led to loss of water and life. On Earth the greenhouse effect has kept the planet at a reasonable temperature allowing for liquid water.

Which of the following correctly describes the meaning of albedo?

The higher the albedo, the more light the surface reflects, and the less it absorbs.

What is the exosphere?

The highest layer in the atmosphere.

What is the troposphere?

The lowest layer of the atmosphere.

What is the thermosphere?

The part of the atmosphere that absorbs X rays.

What is the stratosphere?

The part of the atmosphere that absorbs ultraviolet.

Which of the following worlds has the greatest difference in temperature between its "no atmosphere" temperature and its actual temperature?

Venus

Which of the following worlds has the most substantial atmosphere?

Venus

15. Why is there so much more carbon dioxide in the atmosphere of Venus than in that of Earth? Why so much more carbon dioxide than on Mars?

Venus being closer the Sun has a higher temperature and does not have liquid water to store the CO2. On Earth, CO2 was trapped in the oceans and then into the rocks. On Mars, due to the low mass and lower gravity, CO2 can escape from the surface to space.

11. Describe two anomalous features of the rotation of Venus and what might account for them.

Venus is rotating CW as seen from the North Celestial Pole, the other planets typically rotate CCW. Venus also rotates very slowly on its axis. Astronomers believe both of these occurred because of a large impact during the early formation of the solar system.

20. Is it likely that life ever existed on either Venus or Mars? Justify your answer in each case.

Venus is too hot and does not have liquid water. At present there is no evidence that Venus had a nicer climate in the past. Mars currently is too cold and dry to support life. In the past there is evidence that it was wetter and warmer. Mars may have had life in the past.

Which of the following is not caused by the Coriolis effect on Earth?

Water going down a drain swirls in opposite directions in the Northern and Southern hemispheres.

What is the difference in meaning between the terms weather and climate?

Weather refers to short-term variations in conditions, and climate refers to long-term variations in conditions.

The strength of the Coriolis effect depends on

a planet's size and rotation rate.

Radio communication between distant places on Earth is possible because the

ionosphere reflects radio signals.

There are no aurora on Venus because it

lacks a strong magnetic field.

Convection occurs in the troposphere but not in the stratosphere because

lower altitudes of the troposphere are warmer than higher altitudes, unlike in the stratosphere.

The sky is blue because

molecules scatter blue light more effectively than red light.

Ultraviolet light is absorbed in the

stratosphere.

Sunsets are red because

sunlight must pass through more atmosphere then, and the atmosphere scatters even more light at bluer wavelengths, transmitting mostly red light.