Tuesday, April 24, 2007

Red Dawn

[posted by Callimachus]

The search for an extra-solar earth is one of the great science adventures of our time (unravelling the genome being the other). Chances are, if human civilization still exists 5,000 years from now, and it has a memory, this is what it will remember us for.

It looks like we just might have one.

Too early to tell, though. I'm surprised that it orbits an M-class star -- a "red dwarf" -- because the habitable zone around one of those is pretty tight. But recent discoveries of extra-solar planets with tight, close orbits takes some of the surprise out of it. Still, it makes me wonder what's wrong with our solar system.

Most of the stars nearest the sun -- like most of the stars everywhere -- are these little dwarf-stars which can't be seen from here without a telescope. Our star actually is one of the biggest kids on the block.

This newfound potential Earth orbits a star called GL-581. The name comes from a catalogue of nearby stars compiled in the 1960s. A great many nearby stars -- whose planets are potential targets of human colonization -- only are known by GL numbers. They're too dim to have been noticed or recorded in earlier astronomy catalogues.

"GL" stands for "Gliese," from Wilhelm Gliese, the German astronomer who worked on the catalogue. He died in 1993. Even today, he rates a mere two sentences in Wikipedia. But someday all our children's children's children may know their homes by his name.