This is a false color image of a mosaic of Mercury.
Click on image for full size
Courtesy of NASA.

Discover Mercury

Mercury's orbit is so close to the Sun that it is difficult to see from the ground. This explains why some early astronomers never saw the planet. Viewed from Earth, Mercury is never far from the Sun in the sky. Because of the glare of the Sun, it can only be seen in twilight.

Timocharis made the first recorded observation of Mercury in 265 BC. Other early astronomers that studied Mercury include Zupus (1639), who studied the planet's orbit. Because it is so difficult to make out features on the surface of the planet from Earth, it was not until the 1960s that scientists determined the correct day length rate (59 Earth days) of the planet on its axis. This also showed that Mercury's day length and year length are the same.

The one and only space mission to visit Mercury was Mariner 10, which passed by the planet three times in 1974. Images taken by Mariner 10 are the only close up images we have of the planet's surface. NASA will send the Messenger (the Mercury Surface, Space Environment, Geochemistry and Ranging) to Mercury in 2004.

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