Explore Mercury

Student Planet Facts

Mercury Mercury is the closest planet to the sun. Here are some facts and other places you can find information. When you are ready, click back to return to the Student Center or click below to explore again.

Mercury is a battered and baked planet just larger than Earth's moon. Evidence of heavy bombardment from the chaos of the formation of the solar system is left in the hundreds of craters and resulting lava flows on this small, barren planet. The largest crater is Beethoven at 643 km in diameter and is the largest in the solar system. The largest feature, Caloris Basin, is 1300 km in diameter and was probably caused by an impact from an object larger than 100 km in diameter. Some craters have ice in them even though the planet is so hot because the sun never reaches into the shadows due to the planet's tilt and orbit. With no atmosphere, there is a temperature difference of about 600 degrees between the coldest spots and hottest spots on the planet.

Mercury orbits the sun in about 88 Earth days but takes 58 Earth days to rotate once. On this planet a year takes a (Mercury) day and a half!

Gravity and You
Your weight on Earth is determined by your mass and Earth's mass. Would you weigh more or less on Mercury?

Planet Names
Why are the planets named for Roman gods? What is the story or myth about their names? Click image or here for Planet Myths and Lore.

Could the Earth and an asteroid collide? A huge object smashed into Mercury. What are the chances of it happening to Earth? See what scientists know about Near-Earth Objects.	Can't Find It? Ask Cosmos, the Research Robot.

New! Click here to find out about "The Professor's Telescope", a new book by Chris Moreau, one of our advisors. Take an adventure with Eric to Saturn!

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Quick Facts about Mercury

Topic

Data

Diameter

4879.4 km

Density

5.43 g/cm³

Mass

3.303 x 10²³ kg

Volume

6.084 x 10¹⁰ km³

Temperature Range

-173° C to 427° C

Atmosphere

Some Hydrogen, Helium, Oxygen

Winds

None

Moons

None

Average Distance from Sun

57,910,000 km

Orbital Period

0 Years, 87 Days, 23.3 Hours

Rotation

58 Days, 15.5 Hours

Tilt

0.00°

Rings

None

Composition

Iron Core, Silicate Surface

Magnetic Field

Slight

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