Le coin des amatheurs de sciences version 2 
The sections of the site : The site 
FORUM The space The genetics Medicine Physics Tintin and science Ecology - Nuclear energy Mysteries of the history Humour Diverse
Le coin des amatheurs de sciences version 2
The sections of the site : The site FORUM The space The genetics Medicine Physics Tintin and science Ecology - Nuclear energy Mysteries of the history Humour Diverse
| diameter in km (in miles) | mass compared to the Earth | density | temperature in °C (in °F) | revolution around the Sun | rotation (speed or time) | outdistance compared to the sun in km (in miles) | composition of the atmosphere | |
| Mercury | 4878 (3049) | 0,06 | 5,45 | -170 to 400 (-274 to -688) | 58,646 days | variable ; 150 000 km/h on average | 58 to 90 millions (37 to 56) | rare gases, argon and hélium |
| Venus | 12250 (7656) | 0,82 | 5,15 | 460 (860) | 224 days 16 hours 49 min | 242,98 days | 108 millions (68) | carbon dioxide (97 %), nitrogenizes |
| Earth | 12713 to 12756 (7946 to 7973) | 6x1021 tons | 5,52 | -50 to 50 (-58 to 122) | 365,25 days | 29,80 km/h | 150 millions (94) | nitrogenize (78 %), oxygens (20,9 %) and rare gases up to 10 km then ozone. |
| March | 6828 (4268) | 0,11 | 3,8 | -130 à 30 (-202 to 86) | 687 days | 24 h 37 | variable | carbon dioxide (95 %), nitrogenizes, argon, oxygen |
| Jupiter | 142000 (88750) | 317,83 | 1,36 | -145 ; 30000 in the center (-229 ; 54000) | 11 years 315 days | 9 h 50 min 30 s | variable | helium with 99% |
| Saturn | 107200 to 119700 (67000 to 74813) | 95,15 | 0,7 | -160 (-256) | 29 years 167 days | 10 h 14 | 1430 millions (89) | hydrogen and helium |
| Uranus | 49260 to 50800 (30788 to 31750) | 14 | 1,7 | -220 to -150 (-364 to -238) | 84 years 7 days | 10 h 49 | 2878 millions (1799) | hydrogen (83 %), helium, methane |
| Neptune | 44600 (27875) | 17 | 1,33 to 2,17 | -200 (-328) | 164 years 280 days | 15 h 48 | 4500 millions (2813) | hydrogen, helium, methane |
The natural satellites :
Mercury and Venus don't have satellites, the Earth have one (the Moon), March have two (Phobos and Deimos). The other planetes have a lot of satellites and we sometimes discover new satellites : read the complete lists (in French) : Jupiter - Saturn - Uranus - Neptune.
What about Pluto ? This body was discovered in 1930 (before that, its existence had been shown by calculating its orbit) and was regarded as a planet until August 2006. In 2005, we discovered Eris (2003 UB313) and then problems begin. This body revolve by the Sun but its orbit is so excentric that it doesn't remember a planet. The problem is that we hadn't any real definition af a planet, we just had historical considerations. We didn't want to call Eris a planet, but we had to admit that it's bigger than Pluto.
We had to choose a definition. According to the two best definitions, there would be 8 planets (if we exclude Eris and Pluto) or 12 planets (if we include Eris and the other bodies which are bigger than Pluto). The International Astronomical Union decided in August 2006 : Pluto isn't a planet anymore. (It besides received like Eris the title of dwart planet).