Deck 21: The Moon and Mercury: Comparing Airless Worlds

Question 1

The moon is no longer geologically active because

A) it is rotating too slowly.
B) its radioactive elements were never abundant.
C) it is too small.
D) its crust is too thin.
E) it does not have water on its surface.

Answer 1

it is too small.

Question 2

Slow surface evolution on the moon is limited to

A) low density masses of rock rising from the interior.
B) low level meteorite impacts.
C) small moonquakes disturbing the surface features.
D) motion along a network of small faults.
E) all of the above

Answer 2

low level meteorite impacts.

Question 3

Which hypothesis,concerning the formation of the moon,makes predictions that best fit the observed lunar data?

A) the large impact hypothesis
B) the fission hypothesis
C) the capture hypothesis
D) the co-accretion hypothesis
E) the regolith hypothesis

Answer 3

the large impact hypothesis

Question 4

The time it takes Mercury to complete a solar day (the time from sunrise to sunrise)

A) is equal to two revolutions of Mercury around the sun.
B) is about one earth day.
C) depends on the season of the year.
D) is equal to one revolution of Mercury around the sun.
E) is about one earth year.

Question 5

Mercury has a mass of 3.3*10²³ kg and a radius of 2.4*10⁶ m.The gravitational constant is 6.7*10 ^{- 11} N.m²/kg².What is Mercury's escape velocity?

A) 3,000 km/s
B) 4.3 km/s
C) 9.2*106 m/s
D) 1.8*107 m/s
E) 11.2 km/s

Question 6

The surface temperature of Mercury is

A) about equal to that of Earth's deserts.
B) about equal to that on the bright side of the moon.
C) nearly equal to the surface temperature of the sun.
D) about the same on the day and night sides of the planet.
E) none of the above

Question 7

As the moon revolves around Earth,

A) it keeps one side always towards the sun.
B) it rotates on its axis about once every earth day.
C) it keeps one side always toward Earth.
D) the moon makes two rotations on its axis for every revolution.
E) the moon makes one rotation on its axis for every two revolutions.

Question 8

The co-accretion hypothesis for the formation of the moon suggests that the moon and Earth formed as a double planet from the same cloud within the solar nebula.This hypothesis predicts that

A) the moon and Earth should have nearly the same mass and radius.
B) the surfaces of the moon and Earth should be very similar and show evidence of plate tectonics.
C) the moon and Earth should have identical compositions and densities.
D) all of the above
E) a and c

Question 9

The Earth's moon is airless and inert because its mass is ____ Earth's.

A) much less than
B) much more than
C) equal to

Question 10

The presence of breccias among the lunar rock samples shows that

A) volcanism did not occur on the moon.
B) molten lava once flowed over the lunar surface.
C) the crust must have been made of anorthosite.
D) water once existed on the moon in the form of small lakes and streams.
E) the lunar surface was fragmented by meteorite impacts.

Question 11

In contrast to the Earth and Mercury,the fact that the Earth's moon has no magnetic field implies that

A) the moon is spinning too slowly to produce a magnetic field.
B) the interior of the moon is too hot to produce a magnetic field.
C) the crust of the moon is so thick that the magnetic field can not get out of the interior.
D) the moon's core contains little if any molten iron.
E) the moon is moving farther from Earth.

Question 12

That Mercury has a large iron core is evidenced by

A) the large lobate scarps.
B) the large mean density of Mercury.
C) the lava flows near Caloris Basin.
D) all of the above
E) none of the above

Question 13

The airless and inert nature of the Earth's moon results in ____ craters per unit area as on Earth.

A) more
B) fewer
C) an equal number of

Question 14

The presence of vesicular basalts among the lunar rock samples shows that

A) the lunar surface was fragmented by meteorite impacts.
B) volcanism did not occur on the moon.
C) the crust must have been made of anorthosite.
D) molten lava once flowed over the lunar surface.
E) the moon was once hit by a very large meteorite.

Question 15

If Mercury is 1.5*10⁸ km from Earth and has a diameter of 2,400 km,what is its angular diameter as viewed from Earth?

A) 3.3 degrees
B) 3.3 meters
C) 3.3 radians
D) 3.3 minutes of arc
E) 3.3 seconds of arc

Question 16

The fission theory of the moon's origin has been criticized because

A) the moon is more spherical than Earth.
B) the moon's composition is different from Earth's.
C) the tidal forces are making the moon approach Earth.
D) it requires too many coincidences for it to occur.
E) the moon has a large iron-nickel core.

Question 17

The lunar maria are

A) the lava plains of the lunar lowlands.
B) the smooth plateaus of the lunar highlands.
C) less than one billion years old.
D) moving plates of lunar crust.
E) older than the lunar highlands.

Question 18

The moon's highlands

A) contain a large number of sinuous rilles.
B) are older than the maria.
C) contain relatively few craters compared to the lowlands.
D) were formed as the result of a large meteorite impact on the opposite side of the moon.
E) contain large amounts of sedimentary rock.

Question 19

The escape velocity of the Earth's moon is ____ that of the Earth.

A) greater than
B) less than
C) equal to

Question 20

Why is it surprising that Mercury's magnetic field is strong enough to be measured (> >Earth's moon's),yet significantly weaker than Earth's magnetic field?

A) Mercury's density suggests its core is like Earth's,so its magnetic field should be of nearly equal strength.
B) Mercury is hot enough that its core should be very molten and produce a magnetic field larger than Earth's.
C) Mercury's small size suggests that it should no longer have a molten core,so no magnetic field is expected.
D) Mercury rotates so slowly that it should not be able to produce a magnetic field.
E) Mercury is so close to the sun that its magnetic field should be destroyed by the solar wind.

Question 21

The theory that Mercury shrank slightly when it was young has been proposed to explain...

A) jumbled terrain.
B) large craters.
C) magnetic field
D) lobate scarps
E) central peaks.

Question 22

Mercury's smooth plains are probably the ____________parts of its crust.

A) oldest
B) youngest
C) Cannot tell which are older or younger

Question 23

________ is/are believed to have formed on Mercury just after a giant meteorite created the Caloris Basin..

A) Jumbled lineated terrain
B) The highlands
C) Maria
D) Lobate scarps
E) Heliosynchronous rotation

Question 24

The oldest parts of the surface of Mercury are believed to be

A) the intercrater plains.
B) the smooth plains.
C) lava flows from Caloris Basin.
D) ejecta.
E) vesicular rocks.

Question 25

Major types of surface features or terrain on the Moon are.....

A) highlands
B) maria
C) craters
D) all of the above
E) none of the above

Question 26

The temperature on the daylight side of Mercury

A) is about the same as the night side because Mercury rotates so quickly.
B) is about the same as the night side because of the thick clouds on Mercury.
C) is about 400 $\degree$ hotter than the night side because Mercury rotates very slowly.
D) is about 400 $\degree$ hotter than the night side because one side of Mercury never faces the sun.
E) is hot enough that the surface rocks periodically melt and form lava flows.

Question 27

The theory that Mercury shrank slightly when it was young has been proposed to explain Mercury's

A) extended lava plains.
B) large craters.
C) magnetic field.
D) lobate scarps.
E) regolith.

Question 28

How does the large-impact hypothesis explain why the Moon is poor in heavy elements like iron?

A) The collision occurred too close to the Sun for heavy elements to exist.
B) The impact occurred after Earth had differentiated heavy elements to its center.
C) The collision blew away most of the heavy elements into space.
D) Most of the heavy elements were vaporized in the collision.

Question 29

Slow surface evolution on Mercury is due to

A) micrometeorite impacts.
B) intense cycles of high and low temperature that weakens the surface rocks.
C) plate tectonics.
D) all of the above
E) a and b

Question 30

Which of the terrestrial planets has the most difficult time retaining an atmosphere?

A) Mercury
B) Venus
C) Earth
D) Mars

Question 31

How were the smooth,dark plains called maria formed on the Moon's surface?

A) They were formed by tidal interactions with the Earth very early on in its history.
B) The maria are ancient sites of gigantic impact craters and have smoothed over time.
C) They were formed from lava flows that covered old,cratered lowlands.
D) The maria formed where solar flares touched the surface of the Moon and scarred it.

Question 32

Compared to being on the Earth,a person will weigh about _____ as much on the moon.

A) 1/5=(1/80)/(1/4)²
B) 5 times = (80)/4².
C) 1/80
D) 80 times

Question 33

The moon has _____ as the Earth.

A) 1/5 as much atmosphere
B) 1/80
C) 80x
D) Wrong! The moon has practically no atmosphere at all.

Question 34

____ are believed to have formed on Mercury when the planet's interior cooled and shrank.

A) Jumbled terrain
B) The highlands
C) Maria
D) Lobate scarps
E) Sinuous rilles

Question 35

The moon's distance from Earth is measured very accurately by bouncing a laser beam off of a small mirror left on the surface of the moon.If a laser is fired at the moon and the signal returns in 2.6 seconds,what is the distance to the moon? (Hint: speed of light c = 300,000 km/s)

A) 390,000 km
B) 390,000 m
C) 780,000 km
D) 780,000 m

Question 36

Mercury's major atmospheric gas is

A) oxygen.
B) hydrogen.
C) carbon dioxide.
D) Misleading; the atmosphere is virtually nonexistent.

Question 37

Which of the terrestrial planets has lobate scarps seen as features on its surface?

A) Mercury
B) Venus
C) Earth
D) Mars

Question 38

Caloris Basin on Mercury is believed to be

A) a dry sea floor.
B) an impact basin filled with lava flows.
C) a network of lobate scarps.
D) jumbled terrain.
E) a sinuous rille.

Question 39

The Moon has a diameter of about 3500 km and the Earth 13,000 km.This is about _____ the radial size of the Earth..

A) 1/80
B) 80x
C) 4x
D) 1/4

Question 40

The surface of Mercury is difficult to map from Earth because

A) it is hidden beneath thick clouds.
B) it is never closer than 8 AU to Earth.
C) it is always near the sun.
D) all of the above
E) none of the above

Question 41

The moon still has moonquakes deep in its interior.

Question 42

Lobate scarps are believed to have formed on the moon when its interior cooled and shrank.

Question 43

____________________ protects the Earth from small meteorites while the Earth's moon is ____________________.

Question 44

The Earth's moon has a high escape velocity compared to Earth.

Question 45

The Earth's moon has a dense atmosphere

Question 46

____________________ are long winding channels near the edges of maria that are thought to have been made by lava flows.

Question 47

There were seven successful Apollo mission to the Moon.

Question 48

Mercury is the only terrestrial planet without a moon.

Question 49

Mercury has a(n)____________________ core while the Earth's moon does not.

Question 50

The first Apollo missions to the Earth's moon found the maria to be hard plains of solid lava.

Question 51

The ____________________ hypothesis for the formation of the moon suggests that the moon and earth formed from the same cloud of material and coalesced as two separate objects.

Question 52

On the moon,the maria are younger than the highlands.

Question 53

The vesicular basalts found among the lunar samples were caused by fragmenting during meteorite impacts.

Question 54

The fission hypothesis (i.e.,that the Moon broke off from the Earth early in its history)has been accepted by astronomers as the correct explanation for the origin of the Moon.

Question 55

Mercury's smooth plains are probably the oldest parts of the crust.

Question 56

We know Mercury must have a large metal core because it has a high density.

Question 57

The daytime surface of Mercury is ____________________ than that of the Earth's moon.

Question 58

____________________ are great lava flows covering 17% of the lunar surface.

Question 59

The Earth's moon is less dense than Mercury.

Question 60

In terms of escape velocity,considering Mercury,Earth,and the Earth's moon,____________________ can hold an atmosphere best,with ____________________ next best,and ____________________ least able.

Question 61

The dividing line between daylight and darkness on the Moon is called the ____________________.

Question 62

____________________ formed as Mercury cooled and shrank.

Question 63

____________________ basin is the largest known impact crater on Mercury.