How Big Is the Moon?

Waning Crescent Moon — A waning crescent moon is featured in this image photographed by an Expedition 24 crew member on the International Space Station. (Image credit: NASA)

The moon, or any object, can be measured by diameter or mass. The moon is 3,476 kilometers in diameter. This is small compared to the Earth, which has a diameter of 12,756 kilometers.

The moon’s mass is about 7.35 X 10 to the 22 power (735 with 20 zeroes after it) kilograms while the Earth weighs 5.97 X 10 to the 24 power (597 with 22 zeroes after it) kilograms.

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