Back to Glossary

The Moon

The Moon is Earth’s only natural satellite—a rocky, cratered body about one‑quarter the diameter of Earth, orbiting at an average distance of approximately 384,400 km. It influences tides, stabilizes Earth’s axial tilt, and was formed about 4.5 billion years ago following a collision between Earth and a Mars-sized object.

Source: science.nasa.gov

APODs including "The Moon"

Lunar LOVE

03/11/2018

Lunar LOVE
Image Credit: Junichi Watanabe / NASA APOD

A more creative search by a group of amateur astronomers in the Ehime Prefecture of Shikoku Island, Japan has found lunar L-O-V-E. Their secret was an examination of this sharp image of the First Quarter Moon. To discover it for yourself you'll need to look closely at details of the shadow and light along the terminator, the line between lunar night and day. Created by the contrast of shadowed crater floors with sunlit walls and ridges, the letter V is not too hard to find near the center of the image. Letters L and E are a bit more challenging though, but can be teased out of shadow and light along the terminator at the bottom. Of course, on the cratered surface of the Moon the O is easy ... . Moonwatchers on planet Earth should understand that like the famous lunar X, also seen here, these lunar letters are transient and only appear along the terminator in the hours around the Moon's first quarter phase. So your next chance for lunar L-O-V-E is the first quarter Moon on November 15.