New study dramatically changes where we believe aliens might
live  A team of astrobiologists has redefined conventional
notions of where life can exist within a solar system. They've
suggested that life could exist inside planets with inhospitable
surfaces. Dubbed "subsurface habitable zones," this new
definition of habitable zones means that alien life may be far
more prevalent than we ever imagined.  Typically, a solar
system's habitable zone, or so-called "Goldilocks zone," is a
fairly narrow band within which planets can foster liquid water
at the surface and cling to a stable atmosphere. For our solar
system, this life-imbuing region of space extends from Venus to
Mars.  Scratching the Surface  But as a team of researchers from
Aberdeen and St. Andrews universities are now arguing, this
traditional definition fails to take into account life that can
exist beneath a planet's surface. Indeed, as extremophiles on
Earth have shown, life can be incredibly resilient. What's more,
temperatures increase as depth