Excerpt:
The Moon is the Earth's only natural satellite, circling in a slightly elliptical orbit at 2,300 miles per hour (3,683 km/hr). At this speed, it takes about 27 days to completely encompass the Earth, which is 240,250 miles (384,400 km) away. Although it doesn't revolve around the Sun, because of its size and composition, planetary scientists call the Moon a "terrestrial planet" - akin to Mercury, Venus, Earth and Mars.