Lectures 9-11

Question 1

Explain how the lunar cratering record is used to date the surfaces of other planets

Answer 1

the number of craters on a part of a planetary surface can be used to estimate its age; the more craters, the older the age

Question 2

Mercury’s unique tectonic features

Answer 2

Compressional stresses are dominant. Mercury has contracted 7 km in radius

Question 3

Explain how it is possible that water ice could be present on Mercury’s surface

Answer 3

There are some deep craters at the poles of Mercury that are permanently shadowed which protect/preserve any volatiles present in the craters

Question 4

Describe Mercury in terms of its orbit, length of the day, and length of the year

Answer 4

Orbit: ~1/3 of the distance from the Sun to Earth
Length of the Day: 59 earth days
Length of the Year: 88 Earth Days

Question 5

Describe the surface of Venus as seen from landers

Answer 5

It has a very rough, rocky surface and due to the atmosphere, everything has a yellow tint

Question 6

Evidence for Venus having a differentiated interior

Answer 6

The volcanic and tectonic activity and the CO2 atmosphere

Question 7

Do fracture belts on Venus represent extension or compression?

Answer 7

Extension

Question 8

Do domes on Venus represent extension or compression?

Answer 8

Extension

Question 9

Do rifts on Venus represent extension or compression?

Answer 9

Extension

Question 10

Do ridge belts on Venus represent extension or compression?

Answer 10

Compression

Question 11

Do mountain belts on Venus represent extension or compression?

Answer 11

Compression

Question 12

Describe the effects that the thick atmosphere of Venus has on the geology of the planet

Answer 12

The surface temperature is very hot, there is no water and lots of wind erosion. The rocks undergo lots of erosion, especially chemical erosion

Question 13

Greenhouse Effect on Venus

Answer 13

It occurs a lot faster on Venus. Water and CO2 stay gases, thus causing a runaway effect

Question 14

Explain Venus’ lack of water relative to the Earth (assuming the two planets started with the same amount)

Answer 14

Water vapor was outgassed from the interior, but Venus was too hot for water to condense so it stayed a gas and the vapor was lost to space

Question 15

Lowlands

Answer 15

Relatively flat and smooth; lava flow fronts, long sinuous rilles, ridge belts

Question 16

Uplands

Answer 16

Isolated domes and broad swells; calderas, lava flows, coronae, fracture belts, troughs, rifts

Question 17

Highlands

Answer 17

Plateaus, similar to Earth’s continents; calderas, mountain chains, tesserae, troughs

Question 18

Explain the reason why Mercury’s core is so large

Answer 18

Mercury accreted from a mix that included more metal; because it’s so close to the Sun, it has higher temperatures after accretion which released volatiles; a giant impact stripped the crust away

Question 19

“Hollows”

Answer 19

Irregular, shallow, rimless depressions typically found within craters only on Mercury

Question 20

Impact ejecta blankets on Venus

Answer 20

They have petal-shaped edges and sometimes flow hundreds of kilometers from their impact point

Question 21

Based on the total number of craters, the average age of the surface of Venus is…

Answer 21

750 million years old