Gliese 581 c, d, and e - Possible Habitable Planets

Just 20.3 light years away from earth lay a red dwarf star as old as our own sun named Gliese 581. This star has planets of its own and is the 87th closest star system next to our sun. The Gliese 581 star system is believed to have four planets; Gliese 581 b, c, d, and e.

Artists' impression of the Gliese 581 star system.

Most extra solar planets found by astronomers are closely the size of Jupiter or a lot bigger but Gliese 581c is just one third of the earth's size which means that the planets' gravitational force is just similar to that of our own. Gliese 581c lies in a belt called the habitable zone, an area around a certain star which enables water to be in its liquid form.

Gliese 581c is believed to have a runaway greenhouse effect and is more similar to Venus rather than earth. Just within the border of the habitable zone is the Gliese 581d which is roughly 7 to 14 times the size of the earth. Because it is in the habitable zone, water in this planet could be in liquid form and therefore, life could possibly exist.

In April 2009, astronomers found out that a planet which they named Gliese 581e in the same star system exists and has the size roughly close to earth. So far, this planet has the size closest to that of the earth than any of the extrasolar planets discovered.

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