How is the Moon so bright? I was told by a person that the moon has shiny sand. Is this true?

Your question is a good one and it gets asked a lot at observatory open houses when people are squinting through the eyepiece at the almost painfully bright lunar surface! The answer is that the Moon is actually not very reflective,the Sun is just very bright. The Moon reflects only about 11% of the sunlight that hits it. But the Sun is so bright that even this much reflection looks very bright to us. The rocks on the lunar surface are greyish volcanic rocks, and although there are small glass particles mixed in (which can be shiny), the overall mixture isn't really very reflective.

This page was last updated on July 18, 2015.