Question 1

The Moon is getting farther from Earth.Will this continue forever?

Accepted Answer

Right now, the Moon is moving away from Earth at a rate of about 3.8 centimeters per year. This is due to the tidal interaction between the two bodies. However, eventually, Earth's rotation will slow down until it matches the motion of the Moon. This is known as synchronous rotation. Once this happens, the tidal forces will no longer cause the Moon to move away from Earth, and the recession will come to an end.

Question 2

High tide at your location occurs when the Moon is:

Accepted Answer

The answer of High tide at your location occurs when...

Question 3

The Earth rotates eastward,dragging the tidal bulge raised by the Moon eastward.Suppose the Moon rotated westward around Earth,rather than eastward.How would the dynamics of the Earth-Moon system be affected?

Accepted Answer

If the Moon rotated westward, the tidal bulge would lag behind the Moon's position, causing the Moon to spiral toward Earth instead of away.

Question 4

What are neap tides?

Accepted Answer

Neap tides are a type of tide where the difference between high tide and low tide is at its smallest. This occurs when the gravitational pull of the sun and the moon are perpendicular to each other, causing less of an effect on the tides. As a result, the high tides during neap tides are significantly lower than the average high tide.

Question 5

The Moon,because of the tides in Earth's oceans,is:

Accepted Answer

The Moon is gradually moving away from Earth due to the transfer of Earth's rotational energy to the Moon's orbit through tidal forces, causing the Moon's orbit to slowly spiral outward.

Question 6

Does Earth's gravity raise tides on the Moon today?

Accepted Answer

Earth's gravity can still affect the Moon, raising tides in its interior, particularly if there is a molten core or a plastic mantle.

Question 7

The time between two consecutive high tides at MOST places on Earth is:

Accepted Answer

The time between two consecutive high tides is approximately 12 hours and 25 minutes, which is slightly more than 12 hours. This is due to the Earth's rotation and the Moon's orbit around the Earth.

Question 8

Which statement is a CORRECT description of the Moon's orbit?

Accepted Answer

The Moon is gradually spiraling away from Earth due to tidal interactions, increasing its distance by about 3.8 centimeters per year.

Question 9

Sometimes high tides are higher than at other times.What name is given to the highest high tides?

Accepted Answer

The highest high tides are called spring tides, which occur when the sun, moon and Earth are aligned, causing the combined gravitational pull to create a stronger tidal force. In contrast, neap tides occur when the sun and moon are at right angles to each other, creating weaker tidal forces and lower high tides. Yule tides are a term used for the Christmas season and rip tides refer to fast-moving currents in the ocean.

Question 10

Why is the Moon in a synchronous orbit around Earth,always keeping the same face toward Earth?

Accepted Answer

When the Moon was molten and experiencing chemical differentiation, the gravitational pull of Earth caused large tides. The friction created as Earth's gravity attempted to keep the high tide bulge pointed toward Earth resulted in the Moon's rotation being slowed, causing it always to face Earth.

Question 11

How quickly is the Moon spiraling away from Earth?

Accepted Answer

The Moon is moving away from Earth at a rate of a few centimeters per year due to tidal forces between the Earth and the Moon. This phenomenon is well-documented through laser ranging experiments that measure the distance to the Moon with high precision.

Question 12

Which statement is a CORRECT description of the rotation of Earth?

Accepted Answer

The rotation of Earth is gradually slowing down due to the transfer of energy from Earth's rotation to the Moon's orbit, causing the average length of a day to increase by a few milliseconds per century.

Question 13

How many "tidal bulges" caused by the Moon's gravity are there on Earth?

Accepted Answer

The Moon's gravity causes two tidal bulges on Earth - one on the side facing (almost) directly toward the Moon, and one on the side facing (almost) directly away from it.

Question 14

Which statement describes the dynamics of the Earth-Moon system?

Accepted Answer

The tidal forces between Earth and the Moon are causing the Moon to gradually move away from Earth at a rate of about 1.5 inches (3.8 cm) per year. This causes a transfer of angular momentum from Earth's rotation to the Moon's orbit, which in turn slows down Earth's rotation. Thus, Earth's rotation is slowing down, whereas the Moon is moving slowly outward away from Earth.

Question 15

What can stop the Moon from getting farther from Earth?

Accepted Answer

The Moon's drift away from Earth is caused by tidal forces that pull on its crust and cause its orbit to slowly expand. However, when Earth's rotation slows to match the motion of the Moon (synchronous rotation), the gravitational force of the bulge will end and the Moon will be directly in line with the bulge. At this point, the recession will end and the Moon will no longer drift away from Earth. Option A is incorrect as it is not true that the Moon will always drift away from Earth, while option B is incorrect as the gravitational force of the bulge will not end when the Moon goes beyond the range of Earth's gravity. Option D is incorrect as it suggests that the Moon will spiral inward toward Earth, which is not supported by scientific evidence.

Question 16

Mercury can be seen easily from Earth only:

Accepted Answer

Mercury, which is the closest planet to the Sun, can be seen easily from Earth only when it is near the Sun, just after sunset or just before sunrise. This is because Mercury never strays too far from the Sun in the sky and can only be seen in the twilight glow when it is near the horizon.

Question 17

What are spring tides?

Accepted Answer

Spring tides are high tides that are significantly higher than the average high tide. Spring tides occur when the Earth, Sun, and Moon are aligned in a straight line, which creates a combined gravitational pull on the oceans, resulting in higher-than-normal tides.

Question 18

Two hundred million years ago,during the dinosaur period on Earth,the Moon was:

Accepted Answer

The Moon was closer to Earth 200 million years ago, causing stronger gravitational interactions that resulted in shorter Earth days.

Question 19

How does the speed of Earth's tectonic plates compare with the speed at which the Moon is receding from Earth?

Accepted Answer

The speed at which Earth's tectonic plates move is comparable to the speed at which the Moon is receding from Earth, both occurring at a rate of a few centimeters per year.

Question 20

Sometimes high tides are lower than at other times.What name is given to the lowest high tides?

Accepted Answer

The lowest high tides are known as neap tides.

Quiz 6: The Terrestrial Planets and Their Moons