MercuryNicholas van Niekerk & Ty Thompson (EB)

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The Planet Mercury is the closest planet to our sun and is the smallest planet in the solar system.


History:
Mercury has been studied since the 14th Century BC when it was seen by Assyrian astronomers. The Romans named it Apollo when it was visible in the morning and Hermes when it was visible in the evening. They soon came to realise that it was the same body. The Romans then named the planet after the Roman God, Mercury.
Until the mid-1960's, astronomers believed that Mercury rotated once every 88 Earth days, the same time the planet takes to go around the sun. If Mercury did this, one side of the planet would always face the sun and the other side would always be dark. However, radar studies conducted in 1965 showed that the planet rotates once in about 59 days.


Exploration by man:
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Mariner 10 on duty
  • In 1974 &1975 USA's Mariner 10 spacecraft flew by Mercury three times.
  • In the year 2004 another spacecraft of USA's NASA, named the Messenger Probe was launched into space. It was scheduled to fly by the planet twice in 2008 and 2009 before going into orbit around it in 2011. It is planned to orbit Mercury for one Earth year whilst mapping its surface and studying its composition, interior structure and magnetic field.
  • Japan is planning a joint mission with the European Space Agency. The missions name is BepiColombo and it is scheduled to launch two probes, of which one will orbit it and one will land in its magnetosphere. Both the probes will be launched from Russia in 2013.


Major Characteristics:
  • Volume: 6.083x1000; 0.056 Earths.
  • Mass: 3.30e23 kg (5.5% of Earth's)
  • Diameter: 4,878km (3,032 miles) at its equator, which is about two-fifths of Earth's diameter.
  • Rotation: 58.6462 Earth days. This is a rotation slower than any other rotation except Venus.As a result of the planet's slow rotation on its axis and rapid movement around the sun, a day on Mercury lasts 176 Earth days (interval between one sunrise and the next).
  • Orbit:Orbits the Sun once every 88 days (only 24% of Earths orbit). external image mercury-orbit.gif
  • Distance: -Sun - 57,910,000 km.
- Earth - 150,000,000 km.
  • Gravity: Its gravity is about one third as strong as Earths's.
  • Moons: Mercury has no moons.
  • Temperature: Max. 450 degrees celsius - Min. -170 degrees celsius.
  • Orbit: Mercury has a very elliptical shaped orbit and takes about 88 Earth days to orbit the Sun. This is only about 24% of Earth's orbit.
  • It would take approximately 17360981242.780 seconds for light from the Sun to reach Mercury.
  • Composition: Mercury is one of the densest major bodies in the solar system, second only to Earth. It has a large iron core. Its compostion resembles that of Earth's, in the way that they both have a rocky mantle beneath their crust and an iron core.
  • Magnetic field: Mercury's magnetic field is about 15 of the strength of Earth's.
    external image picture.php?albumid=333&pictureid=2860external image mercury_core2.jpg
  • Surface: The surface of Mercury consists of cratered terrain and smooth plains and many deep craters similar to those on the moon. The largest known crater is Caloris Basin, with a diameter of 1300 km (800 miles).
  • Water: Scans of Mercury done by Earth based radars detect that there is ice in Mercury's poles. However, because craters are so deep sunlight doesnt reacgh the ice and never melts it.
  • Atmosphere: Mercury is too small and hot for its gravity to retain any significant atmosphere over long periods of time. however, it does have a tenuous surface-bound exosphere containing hydrogen, helium, oxygen, sodium, calcium and potassium although this exosphere is quickly blown away by solar winds. It is dry, extremely hot and almost airless.


It is very difficult to see it without a telescope from Earth. at certain times of the year mercury can be seen low in the western sky just after sunrise. at other times of the year it can be seen low in the eastern sky just before sunrise.

=====Description:Mercury is an orange-brown colour. It is very rocky with many craters.

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Did you know???

  • Mercury is the fastest moving planet in our solar system.
  • Mercury is the nearest planet to the Sun.
  • Mercury is the smallest of the four terrestrial planets.