ASTR 9

What evidence would you expect to find on the Moon if it had been subjected to plate tectonics?

The absence of smooth plains, long folded mountains, the equivalent of mid-ocean rifts and rift valleys, the presence of vesicular basalts, and the presence of jumbled terrain.

Does the Moon show evidence of having been subjected to plate tectonics?

Yes.

What evidence supports that Mercury has a partially molten, metallic core?

Mercury has a high density and a weak magnetic field.

Why does the same side of the Moon always face Earth?

The Moon rotates in the same direction that it revolves, and its period of rotation is equal to its orbital period.

What is one consequence of the Moon's small size?

The Moon has no atmosphere, does not have a magnetic field, does not have plate tectonics, and its surface geology is dominated by impact craters.

How does the large-impact hypothesis explain the Moon's lack of iron?

The impacting planetesimal was not differentiated and thus had no iron core.

What is one important way in which both the Moon and Mercury are different from Earth?

They do not have an atmosphere.

Which statement about the Moon is FALSE?

On Earth, we can see all its sides in the course of a month as it goes around us.

Who was the first human being to step out onto the surface of another world?

Neil Armstrong.

Which theory of the Moon's origin do astronomers favor?

The giant impact theory.

Why does the Moon not have an atmosphere?

Because the Moon's mass is so small, its gravity cannot prevent gas molecules from quickly escaping into space.

Where does frozen water primarily exist on the lunar surface?

In craters near the poles.

What are the four main hypotheses for the origin of the Moon?

1. The Moon was once part of the Earth, but they separated early in their history. 2. The Moon formed elsewhere in the solar system and was captured by Earth. 3. The Moon and the Earth formed at the same time, but separately. 4. A large object collided with Earth and ejected a large amount of Earth's mass into space, which became the Moon.