Exam 2 - Chapter 7

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. -Greenhouse gases absorb X-rays and ultraviolet light from the Sun, and this absorbed radiation then heats the atmosphere and the surface. -Greenhouse gases absorb infrared light coming from the Sun, and this absorbed sunlight heats the lower atmosphere and the surface. -The greenhouse effect is caused primarily by ozone, which absorbs ultraviolet light and thereby makes the atmosphere much hotter than it would be otherwise.

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.

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 build up in the atmosphere and strengthens the greenhouse effect.

Which two facters are critical to the existence of the carbon dioxide (CO2) cycle on earth?

Plate tectonics and liquid water oceans.

Which of the following is not an expected consequence of global warming? -an increase in the severity of winter blizzards -melting of polar ice and glaciers -The entire Earth will warm up by the same amount. -an increase in the number and intensity of hurricanes

The entire Earth will warm up by the same amount.

Most of the Moon's surface is densely covered with craters, but we find relatively few craters within the lunar maria. What can we conclude?

The maria formed after the heavy bombardment ended.

Which of the following general statements about Earth's atmosphere is not true? -Gas high in the atmosphere absorbs dangerous X-rays from the Sun. -The nitrogen and oxygen in Earth's atmosphere keep the surface pleasantly warm. -The oxygen in our atmosphere was released by living organisms. -Without the relatively rare gas called ozone, Earth's surface would be bathed in dangerous ultraviolet light from the Sun.

The nitrogen and oxygen in Earth's atmosphere keeps the surface pleasantly warm.

Which of the following best explain what we think happened to outgassed water vapor on Venus? -It turned into carbon dioxide by reacting with nitrogen in Venus's atmosphere. -Water was removed from the atmosphere by chemical reactions with surface rock. -It is frozen as water ice in craters near the poles. -Ultraviolet light split the water molecules, and the hydrogen then escaped to space.

Ultraviolet light split the water molecules, and the hydrogen then escaped to space.

All of the statements below are true. Which one gives the primary reason why the surface of Venus today is some 450°C hotter than the surface of Earth? -Venus has a much higher reflectivity than Earth. -Venus has a higher atmospheric pressure than Earth. -Venus is only about 73% as far from the Sun as Earth. -Venus has a much stronger greenhouse effect than Earth.

Venus has a much stronger greenhouse effect than Earth.

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

Well below the freezing point of water.

Why is the sky blue (on Earth)?

because molecules scatter blue light more effectively than red light.