Planet hunting is by far the hottest area of astronomy these days, and just about everyone who’s in on the search is looking for the same thing: a distant world where life could exist, at least in theory. That means a world more or less the size of Earth, orbiting its parent star in the habitable zone — the location, just the right distance away from its sun’s heat, where water can exist in liquid form. Size or distance alone aren’t good enough: an Earth-size planet that’s too hot or too cold probably couldn’t support life, and a giant gasbag like Jupiter couldn’t either, even if its temperature were ideal.
It’s a pretty strict set of requirements — but maybe not as strict as scientists have assumed. Two new studies, one purely theoretical and the other focused on a known exoplanet, suggest that planets that would on first blush seem too cold to harbor life may be balmier than expected. That means the habitable zone could be a lot wider, and the prospects for alien life more favorable, than anyone thought.
