Chapter 4 (MIDTERM 2)

Question 1

what are the layers of the atmosphere in order from lowest to highest?

Answer 1

troposphere, stratosphere, mesosphere, and thermosphere

Question 2

what causes magnetic field of planets?

Answer 2

the three requirements for a global magnetic field are: 1) an interior region of electrically conducting fluid (liquid or gas), such as molten metal. 2) Convection in that layer of fluid. 3) at least moderately rapid rotation of the planet

Question 3

what are four processes that shape surfaces? (earth’s)

Answer 3

plate tectonics, erosion, volcanism, and impact cratering

Question 4

what is the continental crust like?

Answer 4

made of lower-density rock (ex: granite); much thicker (20-70 km thick);

Question 5

what is the seafloor crust like?

Answer 5

promarily made of dense igneous rock, basalt; typically only 5-10 km thick; radiometric dating shows it is rather young, age ranging from 70-200 million years old depending on which parts

Question 6

what do magnetic fields do for earth and life on earth?

Answer 6

magnetic field protects earth’s surface and atmosphere from solar wind particles. the magnetosphere acts as like a protective bubble surrounding our planet by deflecting most of the solar wind particles while channeling a few toward the poles, where they may cause auroras.

Question 7

what is subduction?

Answer 7

subduction of tectonic plates is the process in which one plate slides under another. usually the dense seafloor plate slides under the continental crust

Question 8

what is solar wind stripping?

Answer 8

solar wind stripping is when a planet’s atmospheric gas is stripped away by the solar wind; this generally affects only planetary atmospheres without a global magnetic field protecting them

Question 9

what is thermal escape?

Answer 9

thermal escape is when atoms or molecules in a planet’s exosphere move fast enough to escape into space

Question 10

what is an atmosphere?

Answer 10

a layer of gas that surrounds a planet or moon, usually very thin compared to the size of the object

Question 11

what causes the temperature profile changes that lead to the different layers of the atmosphere?

Answer 11

the various light waves that are present in the layers are responsible for the temperature profile changes.

Question 12

what is the greenhouse effect?

Answer 12

the process by which greenhouse gases in an atmosphere make a planet’s surface temperature warmer than it would be in the absence of an atmosphere.

Question 13

what are greenhouse gases

Answer 13

they are particularly good absorbents of infrared light but are transparent to visible light;

Question 14

what are the main greenhouse gases on earth?

Answer 14

water vapor, carbon dioxide, and methane.

Question 15

what factors can cause long term climate change?

Answer 15

solar brightening, changes in axis tilt, changes in albedo. changes in greenhouse gases (amount),

Question 16

what is CH4

Answer 16

methane

Question 17

what is outgassing?

Answer 17

the process of releasing gases from a planetary interior, usually through volcanic eruptions

Question 18

what is significant about the Mid-Atlantic Ridge?

Answer 18

this is a significant location on earth because there is new crust/tectonic plates that are forming by a few cm each year. this is the only place where this is happening.

Question 19

(geological) hot spot

Answer 19

a place within a plate of the lithosphere where a localized plume of hot mantle material rises

Question 20

where did earth’s water come from?

Answer 20

outgassing probably released most of the water vapor that condensed to form our oceans as well as most of the gas that formed our atmosphere. comets and asteroids that were made of rock and ice also were responsible for earth’s water.

Question 21

what is Mars like today?

Answer 21

Mars has extreme seasons in southern hemisphere due to its orbit’s ellipticity, has polar ice caps that melt and reform throughout the year (the residual summer ice is mainly water ice), seasonal winds can cause dust storms on Mars, Mars has a crazy tilt that can range from 0 degrees to 60 degrees. this can lead to climate changes

Question 22

what is the difference between weather and climate?

Answer 22

Climate is long-term while weather is ever-varying. weather is less predictable than climate.

Question 23

what causes auroras to occur?

Answer 23

charged particles from solar wind that energize at the upper atmosphere near the magnetic poles.

Question 24

what is the snowball earth?

Answer 24

it is a hypothesized idea suggesting that some 600-700 million years ago, there was a time when Earth became so cold enough that there were glaciers that existed everywhere, even in equatorial regions.

Question 25

what is Venus’ atmosphere like?

Answer 25

thick carbon dioxide atmosphere with a surface pressure 90 times that of the earth. Venus’ slow rotation produces a very weak Coriolis effect. Upper atmosphere has fast winds that are unexplained. Has very reflective clouds composed of sulfuric acid droplets

Question 26

What is Mars’ atmosphere like?

Answer 26

CO2 rich but thin atmosphere; atmospheric pressure is less than 1% that of Earth making the air very thin. Mars lacks an ozone layer = lots of UV

Question 27

What is Titan’s atmosphere like?

Answer 27

200 km thick. much thicker than the Earth’s

Question 28

when did the period of heavy bombardment occur?

Answer 28

during 4.5-3.8 billion years ago

Question 29

what is the runaway greenhouse effect?

Answer 29

“positive feedback loop that won’t stop; keeps getting hotter, water evaporates” a positive feedback cycle in which heating caused by the GHE causes more GH gases to enter the atmosphere, which further enhances the greenhouse effect.

Question 30

relative sizes of terrestrial planets?

Answer 30

(moon), Mercury, Mars, Venus, Earth

Question 31

why does earth have so little CO2 in its atmosphere?

Answer 31

most of the CO2 was dissolved in the oceans, where chemical reactions converted it to carbonate minerals. Unlike Venus and Mars, our CO2 becomes minerals rather than outgassed into the atmosphere.

Question 32

How does the CO2 cycle act as a thermostat for Earth?

Answer 32

It acts as a thermostat through negative feedback processes that returns Earth’s temperature toward “normal” whenever it warms up or cools down. Cool temperatures cause atmospheric CO2 to increase, and warm temperatures cause atmospheric CO2 to decline.