Chapter 10: Planetary Atmospheres

Question 1

What is an atomosphere?

Answer 1

A layer of gas that surrounds a world.

Question 2

What is the greenhouse effect?

Answer 2

A process in which the infared light that is emmited by a planet is absorbed by green house gasses. This increases the overall temperature of the atmosphere.

Question 3

What are greenhouse gases?

Answer 3

Gasses that can absorb infared light.

Question 4

Without the greenhouse effect, what would a planet’s average surface tempurature depend on?

Answer 4

The planet’s distance from the sun.

The planet’s overall reflectivity.

Question 5

What are the four basic layers of Earth’s atmospheric structure.

Answer 5

Troposphere, Stratosphere, Thermosphere, and Exosphere

Question 6

What heats the troposphere?

Answer 6

Infrared light emmited by the ground is absorbed by greenhouse gases. This heats the troposphere.

Question 7

Why does the troposphere have storms?

Answer 7

The heat from the ground causes convection, combined with the relatively high density of air in the troposphere.

Question 8

What heats the stratosphere?

Answer 8

Ultraviolet light which is absorbed by ozone.

Question 9

What effect does the greenhouse effect have on the stratoshphere?

Answer 9

Very little effect as the air density is too low.

Question 10

What is a requirement for a planet to have a stratosphere?

Answer 10

It must contain molecules that are particularly good at absorbing ultraviolet photons such as ozone.

Question 11

Why does tempurature increase with altitude in the stratosphere?

Answer 11

Most of the ultraviolet absorbtion and heating occurs at moderately high altitudes in the stratosphere. This prevents convection.

Question 12

Why is there no weather in the stratosphere?

Answer 12

Because convection is impossible in the lower stratosphere as air gets hotter as altitude increases.

Question 13

What heats the thermosphere?

Answer 13

X-rays from the sun.

Question 14

Why doesn’t the exosphere absorb the x-rays?

Answer 14

The density of the exosphere is too low.

Question 15

What effect is responsible for the ionoshpere?

Answer 15

The ionization of atoms in the thermosphere by x-rays.

Question 16

What is the exosphere?

Answer 16

An extremely low density gas that forms the boundary between the atmosphere and space.

Question 17

What is the magnetosphere?

Answer 17

The protective magnetic field that surrounds the earth

Question 18

What is the function of the magnetosphere?

Answer 18

It deflects the majority of solar wind particles around it

Question 19

What happens to the solar wind particles that get through?

Answer 19

They move allong the magnetic field lines and collect in charged particle belts

Question 20

What is weather?

Answer 20

The ever-varying combination of winds, clouds, temperature, and pressure.

Question 21

What is climate?

Answer 21

The average weather over many years.

Question 22

What would happen to atmospheric heating if earth did not rotate?

Answer 22

There would form two circulation cells. One over each hemisphere of the earth.

Question 23

What is the coriolis effect?

Answer 23

The effect due to rotation that causes air or objects on rotating surfaces to deviate from straigh line tragectories.

Question 24

What are the four major factors that contribute to long term climate change?

Answer 24

Solar Brightening
Changes in Axis Tilt
Changes in Reflectivity
Changes in Greenhouse Gas Abundance

Question 25

What do models say about the brightness of the sun over time.

Answer 25

The models suggest that the sun has increased in brightness over time.

Question 26

How do changes in a planet’s axis tilt affect its climate?

Answer 26

Changes in axis tilt make seasons either more or less extreme.

Question 27

What does a greater axis tilt result in.

Answer 27

More extreme seasons which means warmer summers and colder winters. This prevents ice from building up reducing a planet’s overall reflectivity.

Question 28

What are the three basic ways terrestrial atmospheres gain gas?

Answer 28

Outgassing
Vaporization
Surface Ejection

Question 29

What is outgassing?

Answer 29

The primary source of gases for Venus, Earth, and Mars. Occurs when gas trapped in the earth during accretion is released during a volcanic eruption.

Question 30

What is surface ejection?

Answer 30

Occurs when tiny impacts knock individual atoms or molecules free. This is the explanation for the small amounts of gas that suround the moon and mercury.

Question 31

What are the four main ways terrestrial atmospheres lose gas?

Answer 31

Condensation
Chemical Reactions
Solar Wind Stripping
Thermal Escape

Question 32

What is solar wind stripping?

Answer 32

Occurs when solar wind strips way gas particles into space.

Question 33

What is Thermal escape?

Answer 33

Occurs when an atom or molecule in a planet’s exosphere achieves escape velocity.

Question 34

Do the moon an mercury have atmospheres?

Answer 34

Only low density exospheres.

Question 35

What is the Runaway Greenhouse Effect?

Answer 35

The process in which the green house effect increases globa average temperatures, which in turn increases the intensity of the greenhouse effect. This is known as a positive feedback loop.

Question 36

What are carbonate rocks?

Answer 36

Rocks rich in carbon and oxygen.

Question 37

Why is the temperature of venus so extreme?

Answer 37

The huge amount of carbon dioxide in Venus’s atmosphere results in an intense green house gas.

Question 38

Why does venus experiene little wind?

Answer 38

Slow rotation means a very weak coriolis effect.