Ch 9+10

Question 1

Why is it hard to tell depth on the moon?

Answer 1

You expect to see shades of shadows on a gray scale, but in reality it’s only black and light.

Question 2

Moon Composition

Answer 2

Highlands (83%), Mare/Maria – flat plains of basaltic lava (17%)

Question 3

How do craters form?

Answer 3

Crater hits, “comes out”, and particles fall back into hole that was made

Question 4

Cold Traps on Moon

Answer 4

Where the sun’s rays never shine (poles of moon) ice in crater is unmelted

Question 5

Highlands on Moon

Answer 5

• Made of relatively low-density rock that solidified on the cooling Moon
• Extremely heavily cratered, bearing scars of billions of years of impacts

Question 6

Maria

Answer 6

-dark colored basalt (volcanic lava) laid down in volcanic eruptions years ago

Question 7

Moon’s Surface

Answer 7

• fine grained soil of tiny, shattered rock fragments

- upper layers are porous with loosely packed dust

Question 8

Impact Craters

Answer 8

Regardless of size or angle of impact, they are roughly round & circular

Question 9

Formation of Impact Craters

Answer 9

(1) Impact occurs
(2) Projectile vaporizes and a shock wave spreads through the lunar rock
(3) Ejecta are thrown out of the crater
(4) Most of the ejected materials fall back to fill the crater, forming an ejecta blanket

Question 10

Fission Theory

Answer 10

Moon was once part of Earth, but somehow separated from it early in history

Question 11

Sister Theory

Answer 11

The Moon formed together but independent of Earth

Question 12

Capture Theory

Answer 12

The Moon formed elsewhere in the solar system and was captured by Earth (least likely theory)

Question 13

Avg Distance of Mars from the Sun

Answer 13

227 million kilometers (1.52 AU)

Question 14

Avg Distance of Venus from the Sun

Answer 14

108 million kilometers (0.72 AU)

Question 15

Appearance of Venus

Answer 15

• Appears very bright, featureless white ball
• Goes through phases like Moon
• Planet’s surface not visible b/c of dense clouds that reflect 70% of sunlight

Question 16

Appearance of Mars

Answer 16

• Distinctly red due to iron oxides in soil
• Bright polar ice caps
• Dusky surface markings that sometimes change in outline and intensity

Question 17

Venu’s Surface

Answer 17

Lowland lava plains (75%)

Question 18

Impact Craters on Venus

Answer 18

• Gertrude Stein: Triple impact crater
• Mrs. Piggy Corona
• Mead: Largest crater

Question 19

Atmosphere of Venus

Answer 19

• CO2 (96%) then N2 – overall very dry atmosphere, absence of water
• Huge troposphere
• Almost 800 K on surface

Question 20

Polar Ice Caps on Mars

Answer 20

Mars has 2 year orbit so polar ice caps from 6 month long winter in each hemisphere

Question 21

Percival Lowell

Answer 21

A french astronomer that described what he saw on Mars as channels, but were mistranslated to canals (man-made)

Question 22

Mariner 9

Answer 22

1971, first spacecraft to orbit another planet, mapping entire surface of mars

Question 23

Twin Viking Spacecrafts

Answer 23

1970s, two orbiters surveyed planet and relayed communications for two landers on the surface

Question 24

Mars Global Surveyor (MGS)

Answer 24

• 1997, took high-resolution photos of entire surface for more than one martian year
• Discovered gullies apparently cut by surface water

Question 25

Odyssey

Answer 25

Discovered large amount of subsurface hydrogen

Question 26

Pheonix

Answer 26

-2008, measured water ice in the soil

Question 27

Curiosity

Answer 27

2011, goals include investigations of climate, geology, assessment of habitability of past and present Mars

Question 28

Atmosphere of Mars

Answer 28

• Avg surface pressure of only 0.007 bar
• CO2 (95%), N2 (3%), Argon (2%)
• Winds can reach high speeds but exert much less force than wind on Earth b/c thin atmosphere

Question 29

Runaway Refrigerator Effect

Answer 29

Mars is smaller planet, lower gravity, more and more atmosphere escaped into atmosphere – Mars became cold most of water froze out – further reduced ability to retain heat