|Automatic translation||Updated June 01, 2013|
Besides planets, satellites and asteroids, the solar system contains comets (hair in Greek).
They made for a long time figure of misfortune, disasters and also herald of turnover, for a time when not satisfied with our real troubles, we accumulated it of imagination. It is not the messenger of the misfortune, it is the guard of past, the one who detains the keys of our origin.
Image: images NASA of the comet Wild 2, taken by the probe Stardust in 2004.
A big snowball
We can say that a comet is a big dirty snowball mixed in some dust, having in its center a big pebble. In 1986 a probe went to photograph the very close Halley's comet (600 km) returning extraordinary images of the nucleus the size of which is 16 km on 8 km.
The cloud condenses to give birth to the Sun in the center and any goshawk a gaseous disk flattened in rotation fills with body which circulate everywhere. Some of these bodies agglutinate and form planets. Numerous asteroids in the system and everything in the suburb, the cloud of Oort, reservoir of the future comets remain.
In 2003, the Rosetta probe will be launched by Ariane 5 to achieve 8 years later, the comet Virtanen.
Whom we are...
In 1994 the astronomers observe live a comet (Shoemaker-Levy 9) colliding quite hard the planet Jupiter. This fantasy of the collision becomes a tangible reality for us, in spite of the smallness of the Earth.
Comets and asteroids brought the fundamental elements of the life on Earth and paradoxically could take back it in a single impact.
Some known comets
Image: comet West.
Image: comet Hyakutake.
Image: comet Halley.
Image: comet Hale Boop.
Image: comet Linear
Image: comet Ikeya
The spherical hair of the comet Holmes exceeded the size of the Sun. It measures 1,4 millions kilometers in diameter.
Image: image NASA of November, 2007 Credit and Copyright: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight
The Oort cloud
The solar system is actually much more complex than it seems, if all its objects. A considerable number of small icy objects, sizes similar to that of asteroids, are in the Kuiper Belt and even beyond in the Oort cloud. This invisible and distant region of the solar system hosts billions of light icy body, to limit the attraction of the Sun.
These objects Oort cloud are in a primitive state since their inception, therefore, the materials that formed the solar system at its origin.
Image: The Kuiper Belt and Oort Cloud, are represented at the small blue central task is the space occupied by the solar system as we used to see, consisting of its 8 planets. The Kuiper Belt to a diameter very well above (5 to 10 times) the solar system "classical". The Oort Cloud has a diameter 1,000 times higher than conventional solar system.
Board of the known comets
|Name||Period in years||Name||Period in years|
|Comet Encke||3,30||Comet Daniel||7,09|
|Comet Grigg-Skjellerup||4,90||Comet Harrington-Abell||7,24|
|Comet Honda-Mrkos-Pojdusakova||5,21||Comet Faye||7,38|
|Comet Tempel 2||5,25||Comet Whipple||7,46|
|Comet Neujmin 2||5,43||Comet Ashbrook-Jackson||7,50|
|Comet Brorsen||5,46||Comet Reinmuth 1||7,65|
|Comet Tuttle-Giacobini-Kresak||5,48||Comet Arend||7,79|
|Comet Tempel-Swift||5,85||Comet Oterma 3||7,88|
|Comet Tempel 1||5,98||Comet Schaumasse||8,17|
|Comet Pons-Winnecke||6,30||Comet Wolf 1||8,42|
|Comet Kopff||6,31||Comet Comas-Sola||8,58|
|Comet Giacobini-Zinner||6,41||Comet Vaisälä||10,45|
|Comet Forbes||6,42||Comet Neujmin 3||10,57|
|Comet Wolf-Harrington||6,51||Comet Galle||10,81|
|Comet Schwassmann-Wachmann 2||6,53||Comet Tuttle||13,61|
|Comet Biela||6,62||Comet Schwassmann-Wachmann 1||16,10|
|Comet Wirtanen||6,66||Comet Neujmin 1||17,97|
|Comet d'Arrest||6,67||Comet Crommelin||27,87|
|Comet Perrine-Mrkos||6,70||Comet Tempel-Tuttle||33,17|
|Comet Reinmuth 2||6,71||Comet Stephan-Oterma||38,96|
|Comet Brooks 2||6,71||Comet Westphal||61,73|
|Comet Harrington||6,80||Comet Olbers||65,56|
|Comet Arend-Rigaux||6,81||Comet Brorsen-Metcalf||69,05|
|Comet Holmes||6,85||Comet Pons-Brooks||70,85|
|Comet Johnson||6,86||Comet Halley||76,02|
|Comet Finlay||6,90||Comet Herschel-Rigollet||156,04|
|Comet Borelly||7,02||Comet Rigg-Mellish||164,31|