Scientists once thought that life could originate only within a
solar system's "habitable zone," where a planet would be neither
too hot nor too cold for liquid water to exist on its surface.
But according to planetary scientist Francis Nimmo, evidence
from recent NASA missions suggests that conditions necessary for
life may exist on the icy satellites of Saturn and Jupiter. "If
these moons are habitable, it changes the whole idea of the
habitable zone," said Nimmo, a professor of Earth and planetary
sciences at UC Santa Cruz. "It changes our thinking about how
and where we might find life outside of the solar system." Nimmo
discussed the impact of ice dynamics on the habitability of the
moons of Saturn and Jupiter on Tuesday, December 15, at the
annual meeting of the American Geophysical Union in San
Francisco. Jupiter's moon Europa and Saturn's moon Enceladus, in
particular, have attracted attention because of evidence that
oceans of liquid water may lie beneath their icy surfaces. This
evidence, plus disco