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Saturday, November 03, 2012

Information Mercury



Named after the Roman god of commerce, travel and thievery, Mercury is the closest planet to the Sun and the eighth largest. Mercury's existence has been known of since before the third century BC. The Greeks gave it two names, Apollo for when it appeared as a morning star and Hermes when it came as an evening star.

Mercury has a large iron core which is most likely at least partially molten. The silicate outer shell is only 500 to 600 km thick. It actually has a very thin atmosphere made up of atoms blasted off its surface by the solar wind. Due to the heat of the planet, these atoms quickly escape into space. Thus unlike the Earth and Venus which have stable atmospheres, Mercury's atmosphere is constantly being replenished. 

Mercury is a planet of extremes. Temperature variations swing from 90 K to 700 K. It's hotter on Venus, but with less fluctuations. Mercury also has a very eccentric orbit; at perihelion it is only 46 million km from the Sun but at aphelion it is 70 million.
Mercury has no known moons or satellites.
Mercury orbits closest to the Sun of all the planets, and is the smallest. Mercury's diameter is 4,879 km (3,032 mi), and its volume and mass are about one-eighteenth that of Earth. Discover more information about Mercury, including pictures.

Mercury is so close to the Sun, it is hard to directly observe from Earth, except during twilight. Mercury makes an appearance indirectly, however 13 times each century, Earth observers can watch Mercury pass across the face of the Sun, an event called a transit. These rare transits fall within several days of May 8 and November 10. The first two transits of Mercury in the 21st century oc…

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