All About Mercury

Any vacation on Mercury would be ruined by extreme temperatures. During the daytime, the Sun would appear three times larger and about seven times brighter than it does here on Earth. During the day, temperatures would be as high as 800 degrees F, and at night temperatures could sink to -300 degrees F. Brr!

Mercury is the smallest planet in our solar system. It’s just a little bigger than Earth’s Moon. Mercury itself, though, doesn’t have any moons. It is the closest planet to the Sun, but it’s actually not the hottest. Venus is hotter.

Along with Venus, Earth, and Mars, Mercury is one of the rocky planets. It has a solid surface that is covered with craters. Instead of an atmosphere, Mercury possesses a thin exosphere made up of atoms blasted off the surface by the solar wind and striking meteoroids. Mercury’s exosphere contains sodium, potassium, calcium, magnesium, hydrogen, helium, and other elements.

Mariner 10's first image of Mercury taken on March 24, 1974.

Mercury spins much more slowly than Earth. It takes 59 Earth days for Mercury to spin around once. But because Mercury is the closest planet to the Sun, it doesn’t take long to go all the way around it. A year on Mercury is only 88 Earth days long. If you lived on Mercury, you’d have a birthday about every three months.

What’s more, Mercury’s spin and orbit are in a special arrangement that means there are only three Mercury days every two Mercury years. On Earth we have a sunrise every 24 hours. On Mercury, you would only see one sunrise every 176 Earth days. Isn’t that wild?

Structure and Surface

Time on Mercury

Mercury’s Neighbors

Quick History

What does Mercury look like?

This image shows a beautiful view of Mercury's cratered southern hemisphere.

The MESSENGER spacecraft was the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments, like the MASCS instrument, were used to create this colorful illustration of Mercury’s surface and helped scientists unravel the history and evolution of the innermost planet.

Color differences on Mercury may be hard to see, but they reveal important information about the planet's surface material. A number of bright spots with a bluish tinge are visible in this image. These are relatively recent impact craters.

For more information visit:

Planet Mercury Overview

Explore the Solar System

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