Astronomy Chapter 10

Which of the following worlds has the most substantial atmosphere?

Venus

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

Venus

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

Mercury

Earth’s stratosphere is heated primarily by which process?

Absorption of ultraviolet radiation by ozone.

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

250 K, which is well below freezing.

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.

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

Ultraviolet light is absorbed in the

stratosphere

The ionosphere is a layer of ionized gas that is

within the thermosphere.

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.

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.

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.

A planet with an albedo of 10 percent absorbs 10 percent of the sunlight that strikes it and reflects the other 90 percent.

False

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.

True

Van Allen belts are regions encircling Earth where charged particles get trapped by the magnetosphere.

True

Which process is the primary source of the atmospheric gases on Earth?

outgassing from volcanoes

The energy that warms Earth’s surface comes primarily in the form of __________.

visible light from the Sun

Earth’s temperature remains fairly steady, which means that Earth must return nearly the same amount of energy to space that it receives from the Sun. In what forms does Earth return most of this energy to space?

– visible light reflected by the surface – visible light reflected by clouds – infrared light emitted by the surface and atmosphere

Greenhouse gases in the atmosphere, such as carbon dioxide and water vapor, make Earth warmer than it would be otherwise because these gases __________.

absorb infrared light emitted by the surface

According to scientists, the naturally occurring greenhouse effect makes Earth about 31∘C warmer than it would be if there were no greenhouse gases in our atmosphere. How do scientists "know" what Earth’s temperature would be without greenhouse gases?

They calculate this temperature from Earth’s reflectivity and distance from the Sun.

All of the following statements are true. Which one provides strong observational support for the claim that greenhouse gases make a planet warmer than it would be otherwise?

Venus has a higher average temperature than Mercury.

Based solely on an understanding of the greenhouse effect (as displayed in the figure), which one of the following statements is true?

We should expect an increase in the greenhouse gas concentration to lead to global warming.

Which of the following correctly lists the terrestrial worlds in order from the thickest atmosphere to the thinnest atmosphere? (Note: Mercury and the Moon are considered together in this question.)

Venus, Earth, Mars, Moon/Mercury

Why is the sky blue (on Earth)?

because molecules scatter blue light more effectively than red light

Which of the following general statements about light and Earth’s atmosphere is NOT true?

Visible light from the Sun is absorbed in the exosphere.

The greenhouse effect occurs in the

troposphere

About what fraction of Earth’s atmosphere is CO2?

less than 0.1%

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

Faster rotation rates produce stronger winds.

Venus has a high albedo because its surface is covered by

clouds.

Why does Mars have more extreme seasons than Earth?

because it has a much more eccentric orbit

What is the main reason mountaintops are so cold?

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

What important change in the Sun over the past four billion years is thought to be very important to understanding the climates of Venus, Earth, and Mars?

a gradual brightening with time

In which direction do hurricanes in the Southern Hemisphere rotate?

clockwise

What causes the release of oxygen into Earth’s atmosphere?

photosynthesis

Why is Mars red?

Its surface rocks were rusted by oxygen.

Mars’s distance from the Sun varies from 1.38AU to 1.66AU.
How much does this affect its "no greenhouse" surface temperature at different times of year?

Tclosest−Tfarthest = 20 K

What do we mean by a runaway greenhouse effect?

a greenhouse effect that keeps getting stronger until all of a planet’s greenhouse gases are in its atmosphere

If Earth had as much carbon dioxide in its atmosphere as Venus, our planet would not have oceans.

true

Which of the following statements about the greenhouse effect is true?

– One result of an increased greenhouse effect on Earth may be an increased number of severe storms.
– A weak greenhouse effect operates on Mars.
– Without the naturally occurring greenhouse effect, Earth would be too cold to have liquid oceans.
– The burning of fossil fuels increases the greenhouse effect on Earth because of the release of carbon dioxide.

All of the above are true.

Of the four gases CO2, H2O, N2, and O2, which are greenhouse gases?

CO2 and H2O

Why would the weather become more severe as the greenhouse effect increased?

Warming would increase the evaporation of the oceans, leading to more water in the atmosphere and more frequent and severe storms.

What are fossil fuels?

the carbon-rich remains of plants that died millions of years ago

From where did the molecular oxygen in Earth’s atmosphere originate?

photosynthesis from single-celled organisms

The most recent ice age ended

about 10,000 years ago.

What is the importance of the carbon dioxide (CO2) cycle?

It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate.

When were the heat-trapping effects of gases that cause the greenhouse effect first measured by scientists?

More than 150 years ago.

All the following statements are true. Which two represent the two facts that lead us to expect Earth to be warming up as a result of human activity? Be sure to choose two of the statements below.

– Greenhouse gases make Earth warmer than it would be otherwise. – Human activity is increasing the concentration of carbon dioxide and other greenhouse gases in the atmosphere.

Scientists have confidence in the predictions of today’s best climate models because they __________.

agree well with actual data for recent decades

Which region of Earth has warmed the most in recent decades?

the Arctic

Which of the following is not an expected consequence of the rising carbon dioxide concentration or global warming?

Animal deaths due to carbon dioxide poisoning.

What is the main reason mountaintops are so cold?

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

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.

Which of the following gases absorbs ultraviolet light best?

ozone

What is the exosphere?

the highest layer in the atmosphere

What is the troposphere?

the lowest layer in the atmosphere

The thermosphere is warm because it

absorbs X rays.

Clouds, snow, and ice have higher albedos than rocks.

True

Which of the following is the most basic definition of a greenhouse gas?

a gas that absorbs infrared light

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.

Why does the burning of fossil fuels increase the greenhouse effect on Earth?

Burning releases carbon dioxide into the atmosphere.

What are oxidation reactions?

reactions that remove oxygen from the atmosphere, such as fire and rust