Astronomy 101 Chapter 10; Mastering Astronomy Assignment

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.

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

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.

Most of the X-rays coming from the Sun are absorbed in the _______

thermosphere

The densest layer of the atmospheres of Venus, Earth, and Mars is the _______

troposphere

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.

What happens to the energy that the ground absorbs in the form of visible sunlight?

It is returned upward in the form of infrared light.

Gas particles in Earth's atmosphere most easily escape from the __________

exosphere

The following images represent four types (wavelength bands) of light. Rank these from left to right based on the amount of each that is emitted (as thermal radiation) by Earth's surface, from greatest to least. If you think that two (or more) types should be ranked as equal, drag one on top of the other(s) to show this equality.

(GREATEST AMOUNT) infrared. (visible, ultraviolet, & X-ray light EQUAL AT "LEAST AMOUNT")

The following images show the four terrestrial planets in our solar system. Rank the planets from left to right based on the amount by which the greenhouse effect increases their surface temperatures, compared to what their temperatures would be without the greenhouse effect, from largest to smallest increase.

(LARGEST INCREASE) Venus, Earth, Mars, Mercury (SMALLEST INCREASE)

Make a prediction: If the rise in carbon dioxide concentration continues at its current pace, the concentration in the year 2050 will be about _____ parts per million.

460

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.

On a cloudless day, what happens to most of the visible light headed toward Earth?

It reaches Earth's surface, where some is reflected and some is absorbed.

Based on the evidence that atmospheric carbon dioxide is a cause of planetary warming, what aspect of the graphs should most concern us?

The carbon dioxide concentration today is significantly higher than at any time in the past 800,000 years and is rapidly rising.

On a day with complete cloud cover, what happens to the visible light headed toward Earth?

The clouds reflect much of it back to space, though some still reaches the surface.

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.

On the graphs shown, you can identify an ice age by looking for __________.

a trough (bottom of a dip) on the temperature graph

Earth's ______ absorbs most of the ultraviolet light arriving here from the Sun.

stratosphere

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

the Arctic

In Part A, you found that Earth emits only infrared light. This infrared light can be absorbed by greenhouse gases, such as carbon dioxide and water vapor, in the atmosphere. In fact, all the terrestrial planets emit infrared light from their surfaces. The following images show the four terrestrial planets in our solar system. Rank these planets from left to right based on the total amount of infrared-absorbing greenhouse gases in their atmospheres, from greatest to least.

(GREATEST) Venus, Earth, Mars, Mercury (LEAST)

The following images show the four terrestrial planets in our solar system. Rank the planets from left to right based on the strength of the greenhouse effect occurring at their surfaces, from strongest to weakest.

(STRONGEST) Venus, Earth, Mars, Mercury (WEAKEST)

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? Check all that apply.

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

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

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

agree well with actual data for recent decades

The greenhouse effect raises Earth's surface temperature (from what it would be otherwise) because the infrared light radiated by Earth's surface __________.

is temporarily absorbed by greenhouse gases and then reemitted in random directions

Most of the charged particles from the Sun are deflected around Earth by the _______

magnetosphere

Although the data show only a correlation between the carbon dioxide concentration and the global average temperature, scientists have other reasons to think that a rise in the carbon dioxide concentration actually causes a rise in the global average temperature. All of the following statements are true. Which statements lend support to the idea that carbon dioxide is a cause of planetary warming? Check all that apply.

-Models of the greenhouse effect successfully predict the temperatures of Venus and Mars from their atmospheric carbon dioxide amounts. -We understand the physical mechanism of the greenhouse effect, through which carbon dioxide can increase a planet's temperature. -Models of Earth's climate that include recent increases in the carbon dioxide concentration match observed temperature increases better than those that do not include it.

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

More than 150 years ago.

Notice that the peaks and troughs on the temperature graph occur at the about the same times as peaks and troughs on the carbon dioxide graph. What can we infer from this fact alone?

There is a correlation between the carbon dioxide concentration and the global average temperature.

The average temperature over the past 1000 years has been about 15∘C. From the graphs, you can conclude that Earth's average temperature during the past 800,000 years has __________.

varied between about 7∘C and 19∘C

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

visible light from the Sun