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We are finding new planets in other solar systems all the time. Some of them are in a habitable zone of their sun. Are we able to detect the atmosphere of any exoplanet? Is there any atmospheric element that would be indicative of known life forms?

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up vote 7 down vote accepted

Yes, they are starting to examine exoplanet atmospheres. A spectroscopic analysis is made of the light from a exoplanet transiting its star. The spectra of the star is subtracted from the combined star/planet data, and the remainder is assumed to be the absorption spectra from light passing through the planet's atmosphere. Here's an article from a recent Centauri Dreams column that goes into some detail: Tau Boötis b: A ’3-D’ Look at Star and Planet.

As far as elements indicative of life forms, one would expect to see water, carbon dioxide and methane on a life-bearing planet, but, of course, these are common substances that can readily be explained by natural processes.

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That works for planets detected by the transit method, but do you know of any techniques for planets detected by other methods such as star wobble (radial velocity)? – Chris Mueller Feb 28 '14 at 14:48

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