Lesson 8

Question 1

What is planetary geology?

Answer 1

Geology of the celestial bodies such as planets and their moons, asteroids, comets, and meteorites

Question 2

What are the differences in the planets’ surfaces due to?

Answer 2

They are due to the effects of time (i.e. bombardments of asteroids)

Question 3

What are the hallmarks of the surfaces of Mercury and the Moon?

Answer 3

craters

Question 4

What are the hallmarks of the surface of Venus?

Answer 4

Many volcanoes

Question 5

What is the hallmark of the surface of Mars?

Answer 5

Dry riverbeds and the largest volcanoes in the solar system

Question 6

What is the hallmark of the surface of Earth?

Answer 6

living organisms

Question 7

What is one clue as to the internal structure of a terrestrial planet?

Answer 7

Seismic waves

Question 8

What two ways does earth experience seismic waves?

Answer 8

1. transverse pressure (parallel to the ground)
   - causes P waves (primary waves) to occur
2. perpendicular pressure (pressure towards the ground)
   - causes S waves (secondary waves) to occur

Question 9

Why should we conclude that Earth’s core must have a liquid outer layer?

Answer 9

Because P waves can travel through almost any material, but S waves can only travel through solid material

Question 10

What are seismic waves?

Answer 10

Vibrations that travel through Earth’s interior and surface

Question 11

What are seismigraphs?

Answer 11

instruments used to measure seismic activity

Question 12

What is special about all of the terrestrial planets?

Answer 12

They all have layered interiors

Question 13

How can we categorize the layers of terrestrial planets?

Answer 13

we can categorize them into the core, mantle and crust

Question 14

Describe the core of a terrestrial planet?

Answer 14

Where the heaviest materials, like iron, are

Question 15

Describe the mantle of a terrestrial planet?

Answer 15

Rocky materials like silicon make up the mantle

Question 16

Describe the crust of a terrestrial planet?

Answer 16

Made of granite and basalt

Question 17

What is differentiation?

Answer 17

The fact that gravity pulls high density material to the centre and lower density material rises to the surface

Question 18

What is the likely explanation for why the interior of terrestrial planets are layered?

Answer 18

Because of differentiation

Question 19

Which of the terrestrial planets is the most geologically active?

Answer 19

Earth

Question 20

What three sources of energy explain the internal heat of a terrestrial planet?

Answer 20

1. heat of accretion (from the kinetic energy of planetesmals)
2. heat from differentiation
3. heat from radioactive decay

Question 21

What is radioactive decay?

Answer 21

When the mass energy in nuclei is converted to thermal energy

Question 22

What three processes cool a terrestrial planet’s interior?

Answer 22

1. convection - transports heat as hot material rises and cool material falls
2. conduction -transfers heat from hot material to cool material
3. radiation - sends energy into space

Question 23

What is the lethosphere?

Answer 23

The outer layer of cool, rigid rock (which floats on the warmer, softer rock beneath)

Question 24

What is geological activity?

Answer 24

ongoing changes in a terrestrial planet’s surface

Question 25

Why is size a good control of geological activity?

Answer 25

Because a larger planet can stay hot inside for longer than a small planet

Question 26

Which two terrestrial planets/bodies are geologically dead?

Answer 26

The moon and mercury (there is little heat-driven geological activity)

Question 27

How are magnetic fields created?

Answer 27

When charged particles move at a constant velocity

- heat can create a global magnetic field

Question 28

What does earth’s magnetic core serve to do?

Answer 28

It protects earth’s atmosphere from being stripped away into space by the charged particles

Question 29

What are the three requirements for a global magnetic field?

Answer 29

1. a molten, electrically conducting interior
2. convection
3. moderately rapid rotation

Question 30

Which of the terrestrial planets is the only one to meet the three criteria for a global magnetic field?

Answer 30

Earth

Question 31

What is an atmosphere?

Answer 31

A layer of gas that surrounds a world

Question 32

What does the term “airless” refer to?

Answer 32

That the planet has almost no atmosphere, wind or weather of any kind (i.e. Mercury and the Moon)

Question 33

What is special about Venus’ atmosphere?

Answer 33

It is so thick, that it traps the heat from the sun (so hot that not even robots can survive)

Question 34

What is special about Mars’ atmosphere?

Answer 34

It is so thin that we would die without a pressurized suit

Question 35

What is a bar?

Answer 35

A unit of atmospheric pressure

Question 36

What does 1 bar equal?

Answer 36

1 bar = earth’s atmospheric pressure at sea level (1.03 kg/cm^2 = 14.7 lbs/in^2)

Question 37

How thick is Earth’s atmosphere?

Answer 37

10 km thick

Question 38

What causes atmospheric pressure?

Answer 38

collisions of N2 and O2

Question 39

Why do pressure and density decrease with altitude?

Answer 39

Because the weight of overlying layers is less

Question 40

What is the greenhouse effect?

Answer 40

This only occurs when the atmosphere contains gasses that trap infrared light (ex. water vapour, carbon dioxide and methane)

Question 41

What altitude is considered to be the “edge of space”?

Answer 41

100 km high and over

Question 42

What are the key effects of Earth’s atmosphere?

Answer 42

1. pressure: determines if there is liquid water on the surface
2. light: atmosphere absorbs and scatters light
3. weather: atmospheres create wind, weather and climate
4. magnetosphere: atmospheres interact with solar wind to create a magnetosphere
5. greenhouse effects: atmosphere causes earth’s temperature to be warm enough to allow for liquid water to flow