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Chapter 10 Astronomy

Terms in this set (52)

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 to least amount
infrared
all others the same
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 to least greenhouse gas abundance
venus
earth
mars
mercury
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 to weakest
venus
earth
mars
mercury
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 to smallest increase
venus
earth
mars
mercury
The average temperature over the past 1000 years has been about 15∘C∘C. From the graphs, you can conclude that Earth's average temperature during the past 800,000 years has __________.
varied between about 7∘C∘C and 19∘C
On the graphs shown, you can identify an ice age by looking for __________.
a trough (bottom of a dip) on the temperature graph
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.
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?
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.
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.
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
What motivated Arrhenius to calculate how changes in carbon dioxide might affect the climate?
He was seeking to understand the causes of ice ages.
Using only pencil and paper calculations, Arrhenius concluded that a doubling of the carbon dioxide concentration would raise global temperatures by about _____.
5° C
Arrhenius was not particularly alarmed by his discovery at the time. What changed that made later scientists become much more concerned about the climate effects of carbon dioxide?
Emissions of carbon dioxide rose much faster than Arrhenius had anticipated.
Since the time Arrhenius made his prediction, the carbon dioxide concentration has risen by about 30% and the global average temperature has risen by about 1°C. Which statement below best describes how scientists should evaluate Arrhenius's prediction?
Although Arrhenius's prediction was not exact, the actual change is similar enough to the predicted change to validate the general idea that a rising carbon dioxide concentration would lead to global warming.
Imagine that you visit an alien world that has an atmospheric composition similar to that of Earth (that is, mostly nitrogen and oxygen) and a surface atmospheric pressure of 1.2 bars. Which of the following statements best describes the effects of this pressure?
It will feel quite similar to the atmospheric pressure on Earth.
Put the major layers of Earth's atmosphere in to the correct order from the ground upward.
Drag the layers into place in the correct order from lowest altitude at left to highest altitude at right.
Lowest to highest altitude
troposphere
stratosphere
thermosphere
exosphere
Ultraviolet light from the Sun is absorbed primarily in Eath's stratosphere.
X-rays from the Sun are absorbed primarily in Eath's thermosphere.
Convection and weather occur primarily in Eath's troposphere.
The "edge of space" occurs in the layer we call the exosphere.
The greenhouse effect causes warming primarily in Earth's troposphere.
...
Why doesn't Mars have a stratosphere?
It lacks a layer of ultraviolet absorbing gas.
Early Mars (more than 3 billion years ago)
Strong greenhouse effect.
Substantial volcanism and outgassing.
Some craters held lakes of water.
Core convection.
Strong magnetosphere.
Mars Today
Very weak greenhouse effect.
Surface pressure too low for stable liquid water.
Solar wind strips atmospheric gas.
As you found in Part A, early Mars had both core convection and a strong magnetosphere. What is the connection between these two things?
Core convection helps generate a magnetic field, and the magnetic field creates the magnetosphere.
What key process underlies why Mars changed so much from its early conditions to its conditions today?
Interior Cooling
All of the following statements are true. Which one explains why Mars has lost so much more interior heat than Earth.
Mars is smaller than Earth.
As discussed in the video, the leading hypothesis for why Mars changed holds that interior cooling led to loss of its magnetosphere, allowing the solar wind to strip atmospheric gas away. How has the MAVEN mission provided evidence for this hypothesis?
It has measured rates of gas loss from the atmosphere today.
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 form(s) does Earth return most of this energy to space?
visible light reflected by clouds
infrared light emitted by the surface and atmosphere
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
According to scientists, the naturally occurring greenhouse effect makes Earth about 31∘C∘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.
Click on the first tab at the top of the interactive figure (labeled "The Greenhouse Effect"), then explore what happens as you click among the buttons (labeled "none," "low," "medium," and "high") that adjust the greenhouse gas concentration. Which of the following occur as the greenhouse gas concentration increase?
the average surface temperature rises
more infrared light is absorbed in the lower atmosphere
Now click the second tab (labeled "Terrestrial Planet Temperatures"), then explore what happens as you click the button that allows you to add or remove greenhouse gases. Which terrestrial planet would have its surface temperature the most dramatically changed if its greenhouse gases were removed from its atmosphere?
Venus
Click the third tab (labeled "Global Warming"), then explore the graph and the expanded views you will find by clicking the "?" buttons. Which of the following statements are supported by the data shown?
Rises in global average temperature tend to be closely associated with rises in atmospheric carbon dioxide concentration.
Earth's global average temperature has generally risen over the past century. Atmospheric carbon dioxide levels have risen dramatically over the past century.
Click the fourth tab (labeled "Computer Models"), then explore how the graph changes as you click among the three buttons to its left. What is the primary message of the full graph (with all three curves shown)?
Climate models successfully reproduce the major recent trend in temperature data only if both human and natural factors are included.
Which of the following best describes how the greenhouse effect works?
A planet's surface absorbs visible sunlight and returns this absorbed energy to space as infrared light. Greenhouse gases slow the escape of this infrared radiation, which thereby heats the lower atmosphere.
All the statements are true. Which one gives the primary reason why the surface of Venus today is some 450ºC hotter than the surface of Earth?
Venus has a much stronger greenhouse effect than Earth.
Which of the following statements about Earth's troposphere is not generally true?
It is the layer of the atmosphere in which ozone absorbs dangerous ultraviolet light from the Sun.
In general terms, how do the temperature structures of the atmospheres of Venus and Mars differ from that of Earth?
They lack ultraviolet-absorbing stratospheres.
Does Venus have auroras around its poles, like Earth? Why or why not?
No, because it lacks a global magnetic field.
Why is the Coriolis effect so weak on Venus?
Because Venus rotates so slowly.
All of the following have occurred over long periods of time on Earth. Which one is not thought to have played a major role in long-term changes in Earth's climate?
A gradual rise in the atmospheric content of oxygen.
Why is thermal escape of atmospheric gas much easier from the Moon than from Earth?
Because the Moon's gravity is so much weaker than Earth's.
What is the difference between weather and climate?
Weather refers to short-term changes in wind, rain, and temperature; climate refers to the long-term average of weather.
What would the Venus "no greenhouse" temperature be if its clouds were more transparent, giving a reflectivity the same as Earth's?
T1T1 =
29
∘C∘C
What would the surface temperature be in this example if the greenhouse effect simply increased the surface temperature by the same number of degrees that it does today?
T2T2 =
539∘C∘C
Why is Mars red?
Chemical reactions between surface rock and atmospheric oxygen literally rusted the surface.
Which of the following best explains what scientists think happened to outgassed water vapor on Venus?
Ultraviolet light split the water molecules, and the hydrogen then escaped to space.
What would happen to Earth if we somehow moved our planet to the orbit of Venus?
Earth would suffer a runaway greenhouse effect and become as hot as or hotter than Venus.
Suppose Earth were to cool down a little. How would the carbon dioxide cycle tend to restore temperatures to normal?
Cooler temperatures lead to slower formation of carbonate minerals in the ocean, so carbon dioxide released by volcanism builds up in the atmosphere and strengthens the greenhouse effect.
According to current science, why didn't oxygen begin to accumulate in the atmosphere for more than a billion years after life appeared on the Earth?
Oxygen released by life was removed from the atmosphere by chemical reactions with surface rocks until the surface rock could absorb no more.
Which of the following is not an expected consequence of global warming?
The entire Earth will warm up by the same amount.
Which characteristic of Earth explains why Earth has the ozone necessary for an ultraviolet-absorbing stratosphere?
the existence of photosynthetic life
What does this figure tell us?
The current level of carbon dioxide in our atmosphere is higher than it has been at any time during the past 800,000 years.
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