Astronomy Lecture 7- the Moon
The Earth's rotation is being gradually slowed by the Moon's gravity. True False
True
The Sun causes tides on the Earth in addition to the Moon. True False
True
Until we sent missions to the Moon, no one on Earth had seen the far side of the Moon. True False
True
One difference between the near and far sides of the moon is that ______________________. the far side is almost all rough terrain the far side has no maria All of these choices are correct. the far side is more heavily cratered the far side's crust is mostly anorthosite
All of these choices are correct.
When our Earth becomes tidally locked with the Moon, which of the following statements will be true? The Moon will not go through phases. An astronaut on the Moon would see only one side of the Earth There will be no eclipses. The Moon will only be visible during the day.
An astronaut on the Moon would see only one side of the Earth
Why is the Moon's surface cratered but the Earth's is not? Meteors bounce off the Earth's atmosphere. Earth's impact craters have been mostly obliterated by erosion and plate tectonics. When the dinosaurs died, their remains filled all the Earth's craters. The Moon's stronger magnetic field attracted more iron asteroids.
Earth's impact craters have been mostly obliterated by erosion and plate tectonics.
Planetary scientists believe that the Moon was most likely a nearby small planet gravitationally captured by the Earth. True False
False
The spring tides occur in spring seasons and the neap tides in autumn. True False
False
There is a permanent dark side of the Moon. True False
False
If the Moon was originally a small planet orbiting the Sun, which was then captured by Earth's gravity, what can we predict about the composition of moon rocks collected by Apollo astronauts? Moon rocks should have some similar, and some different compositional characteristics. Moon rocks should have a completely different composition than rocks found on Earth. Moon rocks should have the same composition as rocks found on Earth. Moon rocks should have a composition that is the same as the Earth's crust.
Moon rocks should have a completely different composition than rocks found on Earth.
If the material that formed the Moon was ejected by the Earth due to a rapid rotation rate, what can we predict about the composition of moon rocks collected by Apollo astronauts? Moon rocks should have a composition that is the same as the Earth's crust. Moon rocks should have some similar, and some different compositional characteristics. Moon rocks should have the same composition as rocks found on and inside Earth. Moon rocks should have a completely different composition than rocks found on Earth.
Moon rocks should have a composition that is the same as the Earth's crust.
Why doesn't the Moon have an atmosphere? The Moon's atmosphere was drawn away from it by Earth's stronger gravitational force. The blasts that formed the craters blew it away. The solar wind evaporated the Moon's atmosphere. It had very few volcanoes and the gravity is too weak to hold a substantial atmosphere.
It had very few volcanoes and the gravity is too weak to hold a substantial atmosphere.
If the material that formed the Moon was debris from a collision between the early Earth and another body, what can we predict about the composition of moon rocks collected by Apollo astronauts? Moon rocks should have a completely different composition than rocks found on Earth. Moon rocks should have the same composition as rocks found on and inside Earth. Moon rocks should have some similar, and some different compositional characteristics. Moon rocks should have a composition that is the same as the Earth's crust.
Moon rocks should have some similar, and some different compositional characteristics.
If the Moon formed out of the same cloud of material from which the Earth formed, what can we predict about the composition of moon rocks collected by Apollo astronauts? Moon rocks should have a composition that is the same as the Earth's crust. Moon rocks should have the same composition as rocks found on Earth. Moon rocks should have a completely different composition than rocks found on and inside the Earth. Moon rocks should have some similar, and some different compositional characteristics.
Moon rocks should have the same composition as rocks found on Earth.
How were the maria formed? They were formed by the huge tidal interaction between the Earth and Moon. Maria formed from ash falls from long dead volcanoes. Successive volcanic eruptions flooded huge basins formed by large impacts. Maria were formed by ancient oceans on the Moon's surface.
Successive volcanic eruptions flooded huge basins formed by large impacts.
Which statement about the Moon's orbit is true? The Moon rotates in the opposite direction than it orbits the Earth. The Moon's orbit is aligned with the Earth's orbit. The Moon is in a geosynchronous orbit around the Earth. The Moon is in synchronous rotation as it orbits the Earth.
The Moon is in synchronous rotation as it orbits the Earth.
Why do today's high tides arrive about an hour later than yesterday's tides? The Moon rises and sets about an hour later every day, and the tides follow the Moon. The gravitational pull of the Sun on the tidal bulges slows their flow around the Earth. Friction between the surface of the Earth and the water slow the water's motion. The tidal bulges include dry land as well as water, and dry land responds to the tidal forces more slowly.
The Moon rises and sets about an hour later every day, and the tides follow the Moon.
What does the Moon's lack of a magnetic field suggest about its internal structure? The Moon's core is smaller and cooler than the Earth's. The Moon's interior has not differentiated. The Moon's crust is very thick and poor in iron. The Moon's mantle is too cold to form convection cells.
The Moon's core is smaller and cooler than the Earth's.
How is the Moon's orbit around the Earth different from most major satellite orbits around other planets? The Moon follows an elliptical orbit around the Earth. The Moon orbits much faster than other satellites. The Moon's orbital plane is tipped relative to the Earth's equator. The same side of the Moon faces the Earth throughout its orbit.
The Moon's orbital plane is tipped relative to the Earth's equator.
We can think of the high tide on the side of the Earth opposite the Moon as a result of the Moon pulling the Earth away from the water. True False
True
Why is there a tidal bulge on the opposite side of the Earth from the Moon? The gravitational force from the Moon is stronger on the near side, but the pull of the Earth on the water is stronger on the far side. The far side of the Earth receives a weaker pull from the Moon, and accelerates less than the near side. The Sun creates a tidal bulge as well as the Moon. Centrifugal force makes the far side of the Earth push outward.
The far side of the Earth receives a weaker pull from the Moon, and accelerates less than the near side.
How is the Moon's crust similar to the Earth's? New lunar crust is forming at plate boundaries. All of these choices are correct. The lunar crust is mostly silicate rock. The lunar crust is thicker on one side than the other. Volcanic activity produced most of the craters on the Moon.
The lunar crust is mostly silicate rock.
How is the Moon's mantle different from the Earth's? The lunar mantle extends to the center of the Moon. The lunar mantle is too cold to form convection cells. The Moon's mantle has a higher density than the Earth's. The lunar mantle has a different composition than the Earth's.
The lunar mantle is too cold to form convection cells.
Why do the lunar maria have a darker color than the highland regions? The maria are younger and experienced fewer impacts to weather the surface. The maria have less regolith than the highlands. The maria are composed of different materials than the highlands. The maria are sitting in the shadows of surrounding mountains.
The maria are composed of different materials than the highlands.
Why is the regolith light-colored in the highlands, while darker in the maria? The regolith in the maria has a different mineral composition. The highland regolith is younger, and therefore lighter in color. Lunar regolith is the same color everywhere, but the maria reflect less light. The highland regions receive more sunlight than the maria.
The regolith in the maria has a different mineral composition.
If the Moon orbited the Earth backward, how would tidal interactions change? The Moon would not be tidally locked with the Earth. The tides would arrive about an hour earlier every day. The length of the day on the Earth would increase. The distance between the Earth and the Moon would increase.
The tides would arrive about an hour earlier every day.
Why do we have two high tides per day? There are two tidal bulges, and the rotation of the Earth carries us through both of them every day. The rotation of the Earth and the motion of the Moon around the Earth drag both tidal bulges over us. The Moon and the Sun create separate tidal bulges, resulting in two high tides per day. About half of the Earth's water must flow past more geological barriers, slowing it down.
There are two tidal bulges, and the rotation of the Earth carries us through both of them every day.
How will high tides differ from their average values when the Moon and the Sun are on the same side of the Earth? They will be higher than average. There are no high tides when the Moon is near the Sun in the sky. They will not differ from average values significantly. They will be lower than average.
They will be higher than average.
How will high tides differ from their average values when the Moon is in its full phase? They will be lower than average. They will not differ from average values significantly. They will be higher than average. There are no high tides when the Moon is full.
They will be higher than average.
How will high tides differ from their average values when the Moon is in its new phase? They will be lower than average. They will be higher than average. There are no high tides when the Moon is new. They will not differ from average values significantly.
They will be higher than average.
How will high tides differ from their average values when the Moon and the Sun are 90 degrees from each other in the sky? There are no high tides when the Moon and Sun pull in opposite directions. They will be lower than average. They will not differ from average values significantly. They will be higher than average.
They will be lower than average.
How do the tides slow the rotation of the Earth? Alternating high and low tides create a wobble in the Earth's rotation. The tip in the Moon's orbital plane makes moving the tidal bulges away from the equator more difficult. Tidal bulges move mass away from the center of the Earth, slowing its rotation like a figure skater. Tidal bulges generate drag forces between the Earth and its water, slowing its rotation.
Tidal bulges generate drag forces between the Earth and its water, slowing its rotation.
Solar tides are not as strong as lunar tides mostly because the Sun is much farther away than the Moon. True False
True
Scientists recently confirmed the presence of water ice at the poles of the Moon. Where did this water come from? Water was deposited on the Moon by cometary impacts, and it condensed in deep polar craters. The water is released as polar region crust stretches due to tidal forces from the Earth. The ice is all that remains of the Moon's polar ice caps, present in the Moon's early history None of these choices are correct. Early lunar oceans evaporated quickly, and the water vapor condensed in deep polar craters.
Water was deposited on the Moon by cometary impacts, and it condensed in deep polar craters.
How do we most accurately measure the distance to the Moon? We know how long it took Apollo astronauts to get there, and how fast the rocket traveled. We measure the lunar period and use Kepler's Third Law. All of these choices provide equally accurate measurements. We measure its angular size and compare it to its actual diameter, which gives us its distance. We bounce a pulse of light off the lunar surface and measure how long the trip takes.
We bounce a pulse of light off the lunar surface and measure how long the trip takes.
What is synchronous rotation ? a body's rotation rate that is equal to its orbital period a body's rotation rate that is equal to its parent planet's rotation rate a body's rotation rate that changes with orbital distance a body's rotation rate that does not change with time
a body's rotation rate that is equal to its orbital period
Rilles on the lunar surface were formed by __________________. ancient lava flows the impact of small asteroids the flow of ancient rivers ancient volcano chains
ancient lava flows
The lunar highlands are composed primarily of ____. basalt anorthosite olivine silicon dioxide
anorthosite
What is the composition of the lunar regolith? basalt and olivine anorthosite and basalt silicon dioxide and anorthosite olivine and silicon dioxide
anorthosite and basalt
The lunar maria are primarily composed of ____. basalt olivine anorthosite silicon dioxide
basalt
Heavily cratered, lower-density regions of the lunar surface are called ____. highlands maria regolity rilles Tycho
highlands
The Moon's angular size ____. None of these choices are correct. is higher when the Moon is closer to the Earth is larger during eclipses than at other times is largest at the full moon phase and smallest at the new moon phase does not change as it orbits the Earth
is higher when the Moon is closer to the Earth
Comparing the near and far sides of the Moon, we find that the far side __________________. has as many maria as the near side is more heavily cratered than the near side has a much lower temperature than the near side All of these choices are correct. has regolith composed mostly of basalt
is more heavily cratered than the near side
If the Moon were farther from the Earth, compared to now, the tides would be neap tides would be shallower, and spring tides would be taller than now. less tall all the time. higher all the time. about the same as now.
less tall all the time.
What are rays? canyons, caused by lava flows or crustal cracking long, light streaks of pulverized rock radiating outward from craters mountainous regions areas with no craters at all
long, light streaks of pulverized rock radiating outward from craters
Basalt, a dense congealed lava rock rich in iron, is the primary material in the Moon's far side's regolith. highlands. maria. crust.
maria
The large dark areas on the Moon that form the face of the "Man in the Moon" are called what? maria craters and rays All of these choices are correct. rilles
maria
If high tide is at noon, the next high tide will be at midnight noon tomorrow 6 pm 6 am
midnight
What is the source for the lava that covers the maria? molten rock from impacts rock melted by radioactive heating volcanic eruptions due to subducting lunar crust the original molten surface of the Moon
molten rock from impacts
What we call the Moon's surface layer? maria rilles craters regolith
regolith
Long canyons on the lunar surface are called ____. rifts maria rays rilles
rilles
Which of the following is not a kind of geological feature found on the Moon? rille scarp maria crater
scarp
How many times does the Moon rotate on its axis in one orbital period? The Moon does not rotate. only once twice several times
several times
The majority of lunar craters formed when _________. solid bodies such as asteroids impacted the Moon's surface tidal forces from the Earth cracked the Moon's surface pieces of the Moon fell off, leaving holes in its surface lunar volcanoes erupted
solid bodies such as asteroids impacted the Moon's surface
From the observation that the same side of the Moon always faces the Earth, one can conclude that the Moon does not rotate. the Moon completes one rotation each time it completes an orbit about the Earth. the Moon completes one rotation every day.
the Moon completes one rotation each time it completes an orbit about the Earth.
The primary reason the Moon lacks an atmosphere is because the Earth's gravity pulls away any atmosphere the Moon collects. the Moon lacks sufficient gravity to retain an atmosphere. there is no life on the Moon. the Moon is made up of the wrong kinds of rocks to release atmospheric gases.
the Moon lacks sufficient gravity to retain an atmosphere.
The lunar highlands have more craters than the maria because __________. the maria are much younger than the highlands the maria are much older than the highlands the material composing the highlands is very soft and easily cratered the surface of the maria is liquid and craters quickly disappear there
the maria are much younger than the highlands
The central peak of a crater is formed by __________________. molten rock being thrown upward and then solidifying the upward rebounding of compressed rock None of these choices are correct. ejected material falling back into the crater regolith drifting toward the center of the crater
the upward rebounding of compressed rock
The differential gravitational force of the Moon on the Earth is the cause of ____. phases precession tides the Coriolis force seasons
tides
The distance between the Earth and the Moon remains constant as the Moon orbits about the Earth. varies as the Moon orbits about the Earth.
varies as the Moon orbits about the Earth.
