Friday, April 27, 2007

Aliens' hometown ?

This kind of information becomes almost regular in the space community, but this time it sounds better than ever > A life-friendly planet has been discovered and seems to host the most similar parameters to Earth than we ever know. Nearly 250 exoplanets (planets located outside our beloved Solar System) has been discovered until now, and this one will be the number one focus of scientists. What makes it so special ? (or so "familiar" ?) Let us give its ID :
- Name : Gl 581c (pretty sexy)
- location : Gliese 581 system (red dwarf)
- distance from Earth : 20.5 light years (peanuts)
- Mass : 5 times Earth's
- Diameter : 1.5 times Earth's (making it one of the smallest planet ever discovered)
- about the orbit : the orbit radius is 10.7 millions km with a period of 13 days. Earth is 150 millions km away from the Sun and has a 365 days period. The trick is that Gliese 581 (the exoplanet's sun) is far lighter and colder than the Sun, which makes our exoplanet being situated in the area where water can be liquid.
- consitution : as far as we know today, it is too much lighter to be made of gas. It is then a "rocky" planet, and further analysis will tell if it is an ocean planet, as some scientists guess.
Calculations show that if Gl 581c's albedo is 35% (as it is on Earth), average temperature would be 40°C. But if it is 50%, this temperature would decrease to the very nice value of 20°C, which would make the potential aliens not sweat.

This discovery is due to the great Franco-Swiss team leaded by Michel Mayor, already known for discovering the first exoplanet in 1995. They work on the French observatory located in La Silla, Chile,which hosts powerful instruments such as the VLT (Very Large Telescope) and its awesome adaptative optics system (that enables scientists to get rid of the atmospheric noise by a mirror system that compensates the atmospheric variations in real time).
The team placed the HARPS spectrometer (High Accuracy Radial velocity Planetary Search project - pfooo) on the 3.6m telescope. This instrument is well-known for being "the best exoplanet finder in the world", which is a label that few of us can claim.

The team did not mention yet if they have internet on Gl 581c, and we also don't know if the gravity constant can provide nice conditions for extreme skateboarding. We keep you informed.

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