Wednesday, April 25, 2007

Gliese 581 has a habitable planet

Gliese 581 is a star that is 20.5 light years from us. It is smaller and colder than the Sun: in fact, it is a red dwarf. That's why habitable planets may be much closer to the star.

Gliese 581 c is a planet whose radius is about 1.5 times the radius of Earth. The planet is 14 times closer to the star than our distance from the Sun. But because the star is so much smaller, the planet is expected to have temperatures between 0 and 40 Celsius degrees which is pretty pleasant. Indeed, you can see liquid water on the satellite photograph. ;-)

The planet is about 5 times heavier than Earth. Because the radius is 1.5 times greater than the radius of Earth, the gravitational acceleration is about 5/2.25 = 2 times greater than on Earth. That's why the citizens have somewhat thicker bones: look at the picture.

The Wikipedia article about 581 C informs that a few hours ago, intelligent radio signals arriving from the planet were detected. ;-) This information was added by a witty editor from

See or a video (the first 20 seconds is a commercial).


  1. This planet is also most likely tidally locked to it's star which means no or weak magnetic field which implies the atmosphere and oceans have been lost to space if it ever had them. The entire system formed outside the snow line and moved in displacing the inner planets. The hot Jupiter is probably devoid of it's lighter elements for the same reason,(tidally locked with it's star). I wouldn't start packing my bags any time soon.

  2. Don't be too critical. It may have a thick atmosphere for having 2 earth gravity than distributes heat evenly like venus.Because of a thick atmoshere the polar and night are dont go less than 10 degrees from daytime high. plus life is very tough and thrives places on earth once thouth impossible.The humidity of that planets pretty great so land life will be hard but hydrogen is the best radiation asborber.

  3. An extection to my last comment venus temp. are the same AND Venus also has a slow &/or no rotation just like Gliese_581-C has.Also since it has high gravity it has a thick atmoshere wich needs alot of humidity to equal the water amount of earth so it is hotter and MOST (not all) life will adapt to an acuatic envirment.Also there may be plants that dont use photosythesis but use heat to replace light on the night side since low mass stars live long life has probally atapted to all nitches that means flight in dense atmoshphere,live completly to a high gravity by being smaller, U.V. reflection, all nitches.Plus life in the ocean is easeir because it doesn't have such temp. diference,ease of eating & locomotive and protection againts radiation so i give this planet a 100% of life 85% complex and 12% inteligent sapiens. By the way im only 12 and im smarter than omar581.