Section 2 Earths Moon

Section 2 Earth’s Moon

A. The Moon’s surface
1. Maria—dark-colored areas that look like oceans formed by lava flows
2. Lunar highlands—higher elevation
3. Craters—depressions formed by meteorites striking the surface
B. The Moon’s interior: crust; mantle; small, dense, iron core
C. Motions of the Moon
1. The Moon always keeps the same side facing Earth.
a. It takes the Moon 27.3 days to orbit Earth.
b. It also takes the Moon 27.3 days to rotate once on its axis.
2. Moon phases—As the Moon orbits around Earth, we see different amounts of its sunlit surface.
a. New moon—The Moon is between Earth and the Sun. The lighted part faces away from Earth.
b. The Moon’s phases wax, or grow in size, as the Moon travels around Earth and we see more of the lighted part.
c. Full moon—Earth is between the Sun and the Moon; the entire lighted part of the Moon faces toward Earth.
d. The Moon’s phases wane, or decrease in size, and we see less of the lighted part.
e. The complete cycle takes 29.5 days.
D. Eclipses—shadows cast by Earth or the Moon onto each other
1. Only occur when the Sun, the Moon, and Earth are perfectly lined up
2. Solar eclipse—The Moon blocks sunlight from reaching a portion of Earth’s surface.
3. Lunar eclipse—Earth blocks sunlight from reaching the Moon; the full moon becomes dark.