Good news for those searching for life elsewhere in the universe: a study released today suggests that planets orbiting surprisingly close to their stars can remain livable. This extension of the so-called habitable zone, based on computer modeling, is also important for what it implies about our own planet’s future habitability. Studying habitable zones has always been tricky, because there’s only one habitable planet we know of---our own. Still, astronomers have established the general boundaries for what they call a star’s habitable zone
, the donut-shaped region around that star where an Earth-like planet could host liquid water, necessary for life as we know it. At the zone’s outer edge water freezes from the cold, and at the inner edge it evaporates from the heat; conditions are “just right” inside the zone, hence the area's other common nickname: the Goldilocks zone.
But it’s not as simple as all that, because ...
