By Bruce Gain and Kristen Philipkoski

Scientists seeking habitable planets beyond Earth scored a lucky hit last week with the discovery of Gliese 581c, the first yet found with an orbit in the so-called Goldilocks zone (not too hot, not too cold).

But confirming life there, and in other yet-to-be-discovered systems, will require a new generation of space telescopes capable of picking up "signatures" such as water vapor, carbon dioxide, ozone and methane. NASA and the European Space Agency are developing planet finders that will do just that by 2020, assuming funding comes through.

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