Mercury

Mercury, the planet nearest the Sun, is also the smallest planet in the Solar System. Only slightly larger than the Earth's moon, Mercury's surface is covered with craters. This tiny planet does not have any rings or moons.

Visit another planet: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Dwarf Planets
This historic image is the first ever taken from a spacecraft in orbit about <a href="/mercury/mercury.html">Mercury</a>, the innermost planet of the solar system. Taken on 3/29/2011 by <a href="/space_missions/robotic/messenger/messenger.html">MESSENGER</a>, it shows numerous craters across the <a href="/mercury/Interior_Surface/Surface/surface_overview.html">surface</a> of the planet. Temperatures there can reach over 800F because Mercury is so close to the Sun and rotates so slowly. MESSENGER entered orbit around Mercury earlier in March 2011.<p><small><em>NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington</em></small></p><a href="/mercury/mercury.html">Mercury</a>, the innermost planet of the solar system, is a little bigger than the Earth's Moon. The <a href="/mercury/Interior_Surface/Surface/surface_overview.html">surface</a> of the planet is covered with craters, like the Moon, but temperatures there can reach over 800&deg;F because Mercury is so close to the Sun and rotates so slowly. This picture was taken by the <a href="/space_missions/robotic/messenger/messenger.html">MESSENGER spacecraft</a> in October 2008.<p><small><em>Image courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.</em></small></p>

Explore Mercury

Mercury's Interior and Surface

Mercury, the innermost planet of the solar system, is a little bigger than the Earth's Moon. ...Read more

Atmosphere of Mercury

Mercury has very little atmosphere. The planet's small size means that its gravity is too weak ...Read more

Magnetosphere of Mercury

Mercury is the only terrestrial planet other than the Earth that has a significant magnetic ...Read more

Mercury's Poles

If Uranus is the "tilted planet", Mercury might be called the "upright planet". The spin axis ...Read more

Planetary Facts

All of the relevant information about Mercury collected on one page, including details about size, orbit ...Read more

Myth and Culture

Here are two stories about Mercury, one of the gods in the Roman pantheon. Mercury was identified ...Read more

Missions to Mercury

A table containing information about the spacecraft that have visited Mercury ...Read more

Images and Multimedia

Access wonderful captioned photos and illustrations that will inspire and excite you. ...Read more

Mercury Links

These are links to other great web sites about Mercury. But beware: you don't want to get ...Read more

More about Mercury

Historical Events

Full Earth and Space Science    History Calendar (Members only)

Teacher Opportunities

Full Teacher Events Calendar (Educator Members only)

Did you know?

Did you know that there is a strange hexagon in the atmosphere at the northern pole of Saturn?

Did you know that Thor was the Norse god of thunder, and that he produced thunder with his hammer, Mjolnir?

 

Earth and Space Science Concept of the Day

Do you know what this word or phrase means?

Rayleigh wave
xRayleigh wave : A Rayleigh wave is a seismic surface wave causing the ground to shake in an elliptical motion, with no transverse, or perpendicular, motion.

Click on the word to find out!

Research Highlights

Unprecedented Warming in East Africa's Lake Tanganyika

Lake Tanganyika, the second-oldest and second-deepest lake in the world, could be in for some rough waters. Geologists have determined that the East African rift lake has experienced unprecedented warming...Read more


Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA