Monday, September 18, 2006
So how will we know if we have found life?
Scientists can tell the composition of a planets atmosphere by how light is refracted by it. Different chemicals refract light differently. They call it spectromentry. If a planet had an oxygen atmosphere, or if there was methene in the atmosphere (from living creatures), it would have a distinctive signature that would be readable through a spectrograph.
Knowing this, the good folks at NASA figured they had a good idea what Earth should look like. When they launched the first probe they sent that had a spectrograph on it, they pointed it back at Earth.
It looked just how they thought it would.
Now all astonomers are searching for a new Holy Grail, a planet that has the distinct signature of a planet that carrys Life.