Size: About 1/3 as wide as the Earth

Number of moons: 0

Temperature: -279°F to 800°F. So REALLY cold or REALLY hot depending on if you're in the shade or not!

Mercury is a ball of rock.

Mercury is the planet closest to the Sun. Its grey surface is covered with craters. It would not be very nice to live on Mercury, because it is either REALLY hot or REALLY cold.

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