AST101

Match the descriptions with the correct layers of the Moon's internal structure. Instructions

- Core : paritally molten iron.slightly off center. - Mantle : widest internal region.contains lots of olivine. - Curst : rich in aluminum.where regolith is found.

Match the elements with regions on the Moon where they are likely to be concentrated. Instructions

- Iron, titanium, magnesium: Lunar mare regions.- Calcium, aluminum silicates : Lunar highlands.- Hydrogen, helium : Not prevalent on the Moon.

Select all the choices that are true of the interiors of the Moon and Earth:

-A crust/mantle/core structure -Crusts composed of silicate rocks

Select all the processes important for forming lunar maria.

-Large objects hitting the Moon -Lava from the mantle flooding craters on the early Moon

Earth's ocean plates are rich in basalt and sink down into the mantle at continental edges (subduction zones). However, there are not subduction zones on the Moon at the edge of the maria and the highlands. Select all the reasons why.

-The Moon's interior is cold enough that there are no convection currents. -The Moon's crust is a solid layer.

How long is a day on the Moon?

1 lunar month (the time from full moon to full moon) Reason: Yes, the Moon takes the same time to orbit as to spin. This is why we see only one side of the Moon.

Match each prediction to the appropriate hypothesis of the Moon's formation. Instructions

1. Earth captured a fully formed Moon: Earth and the Moon have very different chemical compositions. 2. Earth and Moon formed at the same time: Earth and the Moon have very similar chemical compositions. 3. The Moon formed from material spun off Earth due to Earth's rapid rotation: The Moon has a chemical composition identical to Earth's crust. 4. The Moon formed as a result of a collision between Earth and a large object: Earth and the Moon share many compositional similarities.

Place the steps of the Moon's formation according to the violent-birth hypothesis in order from start to finish.

1. Earth is struck by a Mars sized object 2. Debris from the collision is hurled into space 3. The debris cools and gravity pulls it together to form the moon 4. The moon's crust solidifies while the interior remains molten 5. Impacts create craters and maria

Arrange the following sentences to describe how impact features are formed on the Moon, from the first step at the top to the last at the bottom. Instructions

1. The impactor hits the Moon's surface at high speed. 2. The impactor disintegrates into a cloud of vaporized rock and fragments. 3. A hole forms, with a size depending on the mass and velocity of the impactor. 4. Vaporized rock forces the surrounding surface rock out into a circular, raised rim. 5. Sometimes the compressed rock beneath the crater rebounds and creates a central peak in the crater.

There are roughly ______ hours between high tide and low tide.

6

Apollo mission results show that Moon and Earth rocks have differences; for example, a lack of low-melting-point metals in Moon rocks. The density and structure suggest the Moon has less iron than Earth. What do these suggest is a likely model of the Moon's formation?

A Mars-sized object hit Earth after Earth differentiated, splattering low-density mantle and crust material into orbit to form the Moon.

Select all that are necessary for tidal braking to occur.

A differential gravitational force exerted on a quickly spinning object Friction between tidal bulges and a spinning object

Which is the best explanation for the formation event shown in the picture of a region on the Moon?

An asteroid or planetesimal hit the young Moon, cracking the surface, and allowed molten rock from the interior to flow up and create a mare.

Use the image to match the expressions and descriptions.

C The average force of the Moon on Earth B-C The strength of the tidal force in the near bulge A The strength of the Moon's gravity at a point on Earth B The strength of the Moon's gravity in the near bulge

Select all that are reasons there is ice on the Moon.

Comets have struck the Moon, vaporizing and depositing water. Deep crater bottoms are shielded from sunlight, so it never gets hot enough to melt ice there.

Select all the features that are found on Earth's Moon.

Craters Highlands Maria

Earth and the Moon are next to each other in space, so why does the Moon have so many more impact craters than Earth?

Earth's craters have been removed by erosion and plate tectonics.

The Moon exerts a tidal braking force on Earth because ____.

Earth's rotation carries the tidal bulge ahead of the Moon Reason: This creates an offset in the direction of the tidal forces, which in turn transfers energy from Earth to the Moon.

True or false: On Earth, tides caused by the Sun are less noticeable than lunar tides because Earth takes a year to orbit the Sun while the Moon only takes a month to orbit Earth.

False Reason: We experience two solar tides (and two lunar tides) each day because Earth rotates. The Sun is much farther away, so the change in its gravitational force from one side of Earth to the other is small.

True or false: The tidal bulge opposite the Moon is caused by the Sun's gravity.

False Reason: Yes! The Sun causes tides, too, but it also causes two bulges. Just as gravity is stronger than the average on the close side, it is weaker on the far side—so Earth is "pulled away" from the second bulge.

What is the best account of the Moon's lack of atmosphere?

Gas present immediately after formation escaped molecule by molecule, because of the Moon's weak gravity and its proximity to the Sun.

Match the label with the layer of the Moon. Instructions

Iron core: CIron-poor mantle: BCrust: A

In what ways is the Moon different from the other large satellites in the Solar System?

It does not orbit directly above the equator of its planet. It is large relative to its planet.

Select all the statements that correctly describe the rays seen on the Moon's surface.

Long, light streaks of pulverized rock Radiate out from craters

Match the name of the feature with the letter.

Mare Regions -B Highland - A Crater - C - D Ray

Select all the lunar features thought to form as a direct or indirect result of impacts.

Maria Craters Lunar rays

If they all formed at the same time, which of the moons shown in the diagram would be the coolest?

Moon B Reason: Yes, moon B has the most surface area compared to its volume because it has the smallest radius, and so it loses heat the fastest.

Match the alignments of Sun, Earth, and Moon tot he type of tides they produce and a time that tide would be maximum.

Spring tide- full moon, new moon, about midnightNeap tide- first-quarter moon, third quarter moon, about 6 am

Which of the following is evidence against the hypothesis that Earth and the Moon formed together side-by-side from a common cloud of gas and dust?

The Moon has a lower fraction of iron than Earth does.

Select all of the reasons the Moon has a heavily cratered surface but Earth does not.

The Moon has no atmosphere. The Moon has little geological activity.

Earth has an atmosphere, but the Moon doesn't. Select all the reasons why.

The Moon has no volcanic activity producing gases. The Moon has too little mass so it lacks enough gravity to hold onto an atmosphere. The Moon is so cold that any gas is frozen onto the surface.

Which details about the Moon are explained by the violent-birth hypothesis?

The Moon's chemical composition is similar to Earth's but not identical. The Moon's iron core is very small for its size. The Moon has little water.

Match the descriptions of their interiors with the Moon, Earth, or both. Instructions

The Moon: solid mantle; thinner crust on one side Earth: completely molten layer in core; strong magnetic field Both: silicate-rich crust; olivine-rich mantle

Why are there more maria on the Moon's near side than on its far side?

The asymmetry in the Moon's interior made the far side crust cool sooner and become thicker. Reason: Yes, the thicker crust on the far side is harder for impacts to puncture.

Select consequences of the Moon's lack of atmosphere.

The sky is black during the day. There are large swings in surface temperature.

How many high and low tides are there per day?

There are two high tides and two low tides per day.

Which is the cause of the Moon's synchronous rotation?

Tidal force from Earth slowed the Moon's rotation.

Match the terms related to tides to their meanings. Instructions

Tide-The regular change in the height of the oceans -Tidal bulge-A bulge in ocean waters caused by the differentialgravitational force of the MoonSolar tides -Tides caused by the Sun; smaller than the Moon's tidesTidal braking -A slowing of Earth's rotation due to drag on the tidal bulges

Which is the best description of a rille?

Which is the best description of a rille?

Select the properties listed that would be true of region B. The other properties are true of region A.

Younger; 3 billion years old Made of basalt

A likely source of water (frozen as ice) on or near the Moon's surface is from ____.

comet impacts

The lunar regolith, shown here imprinted with an Apollo astronaut's bootprint, ____.

covers the surface of the Moon is tens of meters deep is composed of rock pulverized by impacts

The difference between the strong gravitational attraction by the Moon on Earth's near side and the weak attraction on its far side is called a _____________________ gravitational force.

differential

Tidal bulges result ____. (Select all that apply.)

from a "differential" gravitational force from the difference between the force of gravity (from another object) on one side of an object and the force of gravity on the middle

Tidal interactions occur throughout the universe, between planets and moons, black holes and stars, and even between different galaxies. Tidal forces happen because the strength of ______________________ changes with _________________ .

gravity distance

The Moon lacks the convection currents needed to power plate tectonics because ____.

it cooled off faster than Earth

The Moon appears different in the left and right sides of the image because ____.

it has an elliptical orbit angular size depends on distance

The Moon appears larger and smaller at different times because ____ and so its ____ changes.

its orbit is an ellipse; distance from us

The Moon's lack of atmosphere results in a ____ swing of day-night temperature than we have on Earth.

much larger

The streak-like features indicated by the arrows labeled "A" are ____.

rays

The blanket of chunks of rock and fine rock powder that covers the Moon is called .

regolith

The long, straight canyon shown is an example of a lunar ____ that may have been formed by crustal shifting.

rille

Sometimes the Sun's tidal effect on Earth adds to the Moon's, producing a _________ tide. When the Sun's tides occur six hours offset from the Moon's, the resulting weaker tide is called a ____________ tide.

spring neap

The best explanation for why Earth has a tidal bulge opposite the Moon is that ____.

the Moon pulls the center and near side of Earth more strongly than the far side Reason: Yes! The force of gravity on the closer parts of Earth is stronger than the force of gravity on the bulge.

A peculiarity of the Moon's structure is that ____.

the crust is more than twice as thick on the far side than the near side

The force of gravity between the Sun and Earth is stronger than the force of gravity between the Moon and the Sun. However, the Sun's tidal force on Earth is smaller than the Moon's. This is because ____. (Choose the best answer.)

the diameter of Earth is a smaller fraction of the distance to the Sun than it is of the distance to the Moon Reason: Yes. Consequently, the change in the force of gravity over Earth's diameter is bigger for the Moon than the Sun—so the tidal force is bigger.

Right now, as a result of tidal braking, ____. (Select all that apply.)

the distance to the Moon is increasing days on Earth are slowly getting longer Earth only sees one side of the Moon

The tides are strongest on the parts of Earth nearest to (D) and farthest from (B) the Moon. The reason that there are not strong tidal bulges at points A and C is because ____.

the gravitational force of the Moon at the surface at A and C is about the same as the average force of the Moon on Earth

For which of the following properties does the Moon have the largest value compared to the other planetary satellites (not moons of dwarf planets) in the Solar System?

the ratio of satellite mass to planet mass

The differential gravitational force of the Moon acting on Earth causes Earth to slow down, a phenomenon known as ____.

tidal braking Reason: Yes. Earth once rotated so fast a day was only 5 hours long, but now it takes 24 hours.

The Moon's small size relative to Earth explains most of the differences between the two bodies. Its smaller size allows heat to escape more easily from the Moon's interior.

true

The hypotheses for the formation of the Moon make different predictions about the Moon's chemical composition. Select all that are disproved by the fact that the Moon has a composition similar, but not identical, to Earth's.

twin formation hypothesis capture hypothesis fission hypothesis