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:''For information about the NASA project, see [[Project Mercury]].''

:''For information about the NASA project, see [[Project Mercury]].''

[[Mercury]] is the smallest planet in the [[Solar System]], and it is the closest to the [[Sun]].  It orbits the [[Sun]] in 88 (Earth) days. It rotates on its axis every 58.6 days,<ref>"The theory that Mercury is in [[synchronous rotation]] with its orbital motion was shattered in 1965. Astronomers Gordon Pettengill and Rolf Dyce used a radio telescope to make radar observations of Mercury’s spin rate. They found that Mercury’s rotation period is only 58.6 Earth days, not the 88 days accepted for nearly a century." [http://btc.montana.edu/messenger/elusive_planet/modern_times.htm]</ref> which is 3 rotations for every two orbits (called "3:2 resonance").  It can be seen from [[Earth]] only at sunrise and sunset.<ref>[http://www.space.com/spacewatch/mercury_view_030404.html Seeing Mercury at sunset], April 2003</ref>

[[Mercury]] is the smallest planet in the [[Solar System]], and it is the closest to the [[Sun]].  It orbits the [[Sun]] in 88 (Earth) days. It rotates on its axis every 58.6 days,<ref>"The theory that Mercury is in [[synchronous rotation]] with its orbital motion was shattered in 1965. Astronomers Gordon Pettengill and Rolf Dyce used a radio telescope to make radar observations of Mercury’s spin rate. They found that Mercury’s rotation period is only 58.6 Earth days, not the 88 days accepted for nearly a century." [http://btc.montana.edu/messenger/elusive_planet/modern_times.htm]</ref> which is 3 rotations for every two orbits (called "3:2 resonance").  It can be seen from [[Earth]] only at sunrise and sunset.<ref name="spacemag">[http://www.space.com/spacewatch/mercury_view_030404.html Seeing Mercury at sunset], April 2003</ref>

It is named for the Roman messenger god who was known as [[Hermes]] in Greek.

It is named for the Roman messenger god who was known as [[Hermes]] in Greek.

Mercury is one of the five brightest planets, and has been known since ancient times.

Mercury is one of the five brightest planets, and has been known since ancient times.

{{quotebox|In the pre-Christian era, this planet actually had two names, as it was not realized it could alternately appear on one side of the Sun and then the other. Mercury was called Mercury when in the evening sky, but was known as Apollo when it appeared in the morning. It is said that [[Pythagoras]], about the fifth century B.C., pointed out that they were one and the same.<ref>[http://www.space.com/spacewatch/mercury_view_030404.html Seeing Mercury at sunset], April 2003</ref> }}  

{{quotebox|In the pre-Christian era, this planet actually had two names, as it was not realized it could alternately appear on one side of the Sun and then the other. Mercury was called Mercury when in the evening sky, but was known as Apollo when it appeared in the morning. It is said that [[Pythagoras]], about the fifth century B.C., pointed out that they were one and the same.<ref name="spacemag"/> }}  

== Orbital oddities ==

== Orbital oddities ==