Gray planet Mercury with craters and rays of material ejected by impactors like asteroids.

Mercury

Mercury is the closest planet to the Sun, and the smallest planet in our solar system - only slightly larger than Earth's Moon.

Mercury Facts

Mercury is the smallest planet in our solar system and the nearest to the Sun.

Mercury is only slightly larger than Earth's Moon. Its surface is covered in tens of thousands of impact craters. Despite its proximity to the Sun, Mercury is not the hottest planet in our solar system – that title belongs to nearby Venus, thanks to its dense atmosphere. But Mercury is the fastest planet, zipping around the Sun every 88 Earth days. Mercury is appropriately named for the swiftest of the ancient Roman gods.

Get the Facts
Gray-colored Mercury with bright ejecta visible in craters.
NASA's Mercury MESSENGER took this image of Mercury's southern hemisphere. The bright rayed crater near the limb is Debussy, named for the impressionist era French composer.
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Mercury By The Numbers

How big is Mercury? How far is it from the Sun?

Use this tool to compare Mercury to Earth, and other planets.

Analyze and Compare
A gray, cratered world in the blackness of space, with about two-thirds of the planet illuminated by sunlight coming from the right. The overall gray shows some tan tints in some areas, and several craters have slivery-white rays extending outward from them, across the surface.
NASA's MESSENGER spacecraft captured a part of Mercury not previously seen by spacecraft after its closest approach to the planet on Jan. 14, 2008.
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie

Exploring Mercury

The first spacecraft to visit Mercury was NASA's Mariner 10, which imaged about 45% of the surface.

NASA's MESSENGER spacecraft flew by Mercury three times and orbited the planet for four years before crashing on its surface at the end of its mission. The European Space Agency and JAXA launched a joint mission to Mercury in 2018. The mission, called BepiColombo, is made up of two spacecraft.

Learn More About Mercury Missions
An illustration of the MESSENGER spacecraft at Mercury.
NASA's MESSENGER spacecraft is shown near Mercury in this illustration.
NASA

Mercury Resources

Explore this page for a curated collection of resources about Mercury.

This resources page includes activities that can be done at home, as well as videos and animations, images, and printable graphics. This content is for educators, students, and anyone interested in learning more about Mercury!

Explore Resources for Mercury
Mercury in several different colors
This image from NASA's MESSENGER spacecraft uses spectral data to highlight various minerals, features and properties on Mercury.
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Eyes on the Solar System lets you explore the planets, their moons, asteroids, comets and the spacecraft exploring them from 1950 to 2050.
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