Terrestial Planets

Question 1

Name the terrestrial planets

Answer 1

Mercury, Venus, Earth, Mars

Question 2

Where are terrestrial planets located?

Answer 2

0.4-1.52AU

Question 3

What are typical density of terrestrial planet?

Answer 3

~5000kg/m^3

Question 4

How did the moon form?

Answer 4

Thought to be result of massive collision as the planets were forming

Question 5

How do we know how moon formed?

Answer 5

•too big for earth to capture
•tidally locked
•composed of material similar to earths mantle and lithosphere
•small core
•age of surface rocks similar to age of solar system

Question 6

Impact Cratering

Answer 6

Form when an asteroid or comet hits the surface of a planet
•crater generally 10 times as wide as the object and has depth similar to object size

Question 7

Which terrestrial planet has been subject to most crater bombardment?

Answer 7

All the same

Question 8

Why was crater bombardement heavier in early solar system?

Answer 8

Still a lot of debris left over from the Proto-planetary disk

Question 9

What is the core?

Answer 9

Densest material-metals such as nickel and iron

Question 10

What is the mantle?

Answer 10

Rocky material of modest density-minerals containing for example silicon and oxygen

Question 11

What is the crust?

Answer 11

Lowest density rocks-e.g., granite, basalt

Question 12

What is the lithosphere?

Answer 12

Outer shell of most solid rock

Question 13

What are the two types of earthquakes?

Answer 13

•P waves-longitudinal
•S waves-transverse

Question 14

What waves are stopped by molten outer core?

Answer 14

P Waves (S waves can only travel in solids)

Question 15

What allows us to develop a model of earths interior?

Answer 15

Analysis of seismic waves

Question 16

How do we know interior structure of other planets?

Answer 16

Detailed mass and shape measurements

Question 17

What are the 3 internal heat sources?

Answer 17

Heat of accretion, heat from differentiation, heat from radioactivity

Question 18

What is heat of accretion?

Answer 18

Accreting planetesimals release gravitational potential energy

Question 19

What is heat from differentiation?

Answer 19

As dense material sinks it also releases gravitational potential energy

Question 20

What is heat from radioactivity?

Answer 20

Rocks and metals contain radioactive isotopes that release energy when they decay

Question 21

How do planets cool?

Answer 21

Planets lose internal heat by transporting the energy to the surface and radiating it away: convection, conduction, radiation

Question 22

When does volcanism occur?

Answer 22

When underground molten rock finds its way through the lithosphere to the surface

Question 23

What are the different volcanoes?

Answer 23

•Plains like in moon formed by runniest lava flattening out
•shield volcanoes formed by thicker lava (Hawaii/mars)
•strato-volcanoes formed by thickest lava(earth)

Question 24

What is tectonics?

Answer 24

Any surface reshaping process
•stretching or compression of the lithosphere

Question 25

What is erosion?

Answer 25

•breakdown of rock through action of ice,liquid, or gas

Question 26

How are craters erased?

Answer 26

•formed by bombardement but can be erased by activities such as volcanism, tectonics, and erosion( driven by internal heat)

Question 27

Describe the lunar Maria?

Answer 27

•smooth •formed by a flood of lava •Maria lava heated by radioactive decay in first few hundred mill years after formation

Question 28

What does lack of craters in Maria imply?

Answer 28

Early heavy bombardment and very few impacts afterwards

Question 29

Describe Mercurys surface

Answer 29

•heavily cratered, some lava plains •Some very high cliffs( contraction of core and mantle,deforming crust) •Caloris Basin (crater half of radius)

Question 30

Describe Venus’s surface

Answer 30

•many lava plains and volcanoes, contorted crust •no erosion evident as no wind •crater count suggests surface age of 750 million yrs

Question 31

Why is earths lithosphere broken into different plates?

Answer 31

Forces of underlying mantle convection

Question 32

Why does Venus have no plates?

Answer 32

•thicker and stronger lithosphere •could be because water evaporated faster on Venus than on earth

Question 33

Describe Mars’s surface

Answer 33

•southern hemisphere more heavily cratered than the north( southern surface older) •geological activity has erased craters in north •north lower elevation •large impact basin in south

Question 34

How high is Olympus mons?

Answer 34

26km

Question 35

Why is Olympus mons volcano bigger than earths?

Answer 35

Moving tectonics on earth cause volcano hotspots to move

Question 36

Describe water on Mars

Answer 36

•mainly in the form of polar ice, up to a metre thick •ancient water flow:sedimentation •recent water flows:•gullies and craters and liquid water unstable •radar reveals liquid water lakes under ice caps