The first planet from the Sun in the solar system. Mercury orbits the Sun at an average distance of 0.4 times Earth's distance. The planet is just five percent as massive as Earth, and it about 50 percent larger than the Moon. It is made of solid, rocky material that is heavily cratered, and it has no significant atmosphere. Mercury has no moons.


Exploring Our Own Back Yard The four planets closest to the Sun -- Mercury,...
Mercury Tiny, cratered Mercury is the closest planet to...

Radio Programs

General Relativity III Proof that Einstein was right Wednesday, November 25, 2015
Morning Mercury A dark planet in the dawn sky Saturday, October 10, 2015
Evening Mercury Measuring a planetary day Sunday, April 26, 2015
Venus and Mercury Pointing the way to a little planet Saturday, January 10, 2015
Morning Mercury Getting closer to a little planet Thursday, October 30, 2014
Venus and Mercury Bright, hot planets in the dawn sky Friday, July 11, 2014
Moon and Mercury Ghostly apparitions in the evening sky Friday, May 30, 2014
Evening Mercury Shrink-wrapping a small planet Thursday, May 15, 2014
Mariner 10 at Mercury A first look at a little planet Saturday, March 29, 2014
Mercury in the Morning An irritating planet in the dawn twilight Friday, March 14, 2014
Evening Mercury The wrinkled skin of a small planet Friday, January 31, 2014
Moon and Planets Two planets wander across the sky Saturday, November 30, 2013
Dawn Planets Siblings with no family resemblance Sunday, November 24, 2013
Venus and Mercury Artists land on another world Monday, June 17, 2013
Mercury Rising Cold pockets on a hot planet Tuesday, May 28, 2013
Mercury in the Evening A visit from a reticent planet Saturday, February 16, 2013
Moon and Mercury Some interesting sunrises and sunsets Tuesday, August 14, 2012
Moon, Venus, Mercury Getting close to the Sun Monday, August 13, 2012
Moon and Mercury Peering into a small planet’s big heart Thursday, June 21, 2012
Mercury in the Morning Teasing out a view of Mercury Monday, April 16, 2012
Evening Mercury Rethinking the birth of a planet Monday, March 5, 2012
Friendship 7 Getting back in the Space Race Monday, February 20, 2012
Morning Mercury A confusing planet in the morning sky Friday, September 2, 2011
Evening Mercury A hot planet in the evening sky Monday, July 18, 2011
More Moon and Mercury Looking into the heart of a planet Sunday, July 3, 2011
Moon and Mercury Getting to know a hard-to-see planet Saturday, July 2, 2011
Mercury in the Morning A planet with a message Wednesday, May 4, 2011
Messenger at Mercury II Probing a planetary bowling ball Wednesday, March 16, 2011
Messenger at Mercury Clearing up the view of an elusive planet Tuesday, March 15, 2011
Mercury and Jupiter Big and small in the evening sky Monday, March 14, 2011
Urbain Leverrier A "calculated" planetary discovery Friday, March 11, 2011

Featured Images

View of Mercury from Messenger spacecraft
Dark Planet Saturday, October 10, 2015
The Messenger spacecraft's final image of the surface of Mercury
The End Thursday, April 30, 2015
Messenger view of the surface of Mercury
Getting Closer Thursday, October 30, 2014
Venus, Mercury, and the earthshine-illuminated crescent Moon
Lighting the Shadows Friday, May 30, 2014
Mariner 10 at Mercury
First Encounter Saturday, March 29, 2014
MESSENGER view of crater Degas on Mercury
Painting a Planet Monday, June 17, 2013
Messenger view of Mercury's southern hemisphere
Hard-to-Study Planet Friday, September 2, 2011
Messenger view of the surface of Mercury, June 2011
Hello, Sunshine Saturday, July 2, 2011
MESSENGER's first color image of Mercury, March 29, 2011
First Glimpse Thursday, March 31, 2011
Artist's concept of Messenger orbiting Mercury
Safe Arrival Friday, March 18, 2011
Planetary Tail Tuesday, April 6, 2010


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