Sunday, April 29, 2007
"That's what makes Gliese special. Like Earth, it is a small planet — 1.5 times Earth's diameter, in fact. Planets of that size are not blobs of gas but rocky. It also orbits its parent sun at a distance where liquid water could exist (the estimated temperature is between 0 and 40 degrees). And liquid water could mean life. It is, in other words, the first potentially habitable planet.
Nevertheless, Gliese would be an odd place. The planet gets enough warmth only because it orbits its faint, cool sun very closely. That produces several interesting side-effects.
It has a "year" of only 13 days and tides 400 times stronger than Earth's. It also may be tidally locked — one side scorching, always facing its sun; the other, freezing cold, always facing away, with only a temperate "twilight zone" between capable of hosting life."
Also: "Planet hunters find promise of life"