Mercury (Planet)
Symbol |  |
Mean distance from The Sun | 0.387 a.u. |
Sidereal Period | 87.969 days |
Rotation Period | 58.6461 days |
Mass | 0.056 Earth |
Diameter | 4880 km |
Mercury is the innermost planet in our solar system and the quickest to orbit the Sun.
Atmosphere
No appreciable atmosphere exists on Mercury. Helium is present at a surface pressure of 10-9 millibars.
Surface
Mercury has a crated surface and is similar in appearance to Earth's Moon. The largest surface feature on Mercury is the Caloris Basin.
Interior
The interior contains a large core of iron. At about 1800 kilometres in diameter this core is slightly larger than the overall size of our Moon. Between the surface of Mercury and it's core lies a mantle of silicate material.
Locating Mercury
Mercury, smallest of the terrestrial planets and closest to the Sun. With it's orbit being so close to the Sun it is a tricky object to spot and it can only be see just after sunset or just before sunrise. As it is easy to mistake Mercury for a star the best way to find it is to check star charts or use a piece of software such as Redshift or Stellarium to find it's location.
Finding Mercury can be made easier if it happens to be near another brighter planet in the sky (see image below) then it is just a matter of locating the brighter planet to find Mercury nearby.
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The above image is a reconstruction of the positions of Venus, Mercury and Jupiter as they appeared in the sky on 2 Jan 2009. Mercury can be seen just a few degrees from Jupiter. |
Mercury's orbit is inside that of the Earth's so it can also be seen as a silhouette when it transits the Sun.
Further Reading
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This page was last modified on Sunday, May 02, 2010 08:11:41 PM