How Big is the Moon?

Article written: 28 Dec , 2009
Updated: 24 Dec , 2015

The Moon is one of the most significant objects in the night sky, second only in brightness to the Sun. So, how big is the Moon?

The diameter of the Moon is only 3,474 km across. Just for comparison, the diameter of the Earth at the equator is 12,756 km. That’s only 27% the diameter of the Earth. The Moon is also the 5th largest moon in the Solar System, after Ganymede, Titan, Callisto and Io.

In terms of volume, the Moon only contains 2.195 x 1010 km3. That sounds like a lot of cubic kilometers of Moon, but again, that’s only 2% the volume of Earth.

The surface area of the Moon is 3.793 x 107 km2. That’s about the same size as Russia, Canada and the United States combined.

The circumference of the Moon is 10,921 km. Again, that’s only a little over a quarter the circumference of the Earth.

We’ve written many articles about the Moon for Universe Today. Here’s an article about the Moon compared to Earth, and here’s an article about the mass of the Moon.

If you’d like more info on the Moon, check out NASA’s Solar System Exploration Guide on the Moon, and here’s a link to NASA’s Lunar and Planetary Science page.

We’ve also recorded several episodes of Astronomy Cast about the Moon. Listen here, Episode 113: The Moon, Part 1.

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