The Cassini probe may have already collected data that could
reveal the presence of life on Saturn's moon Enceladus, a new
study argues. But mission scientists say teasing out the subtle
signature of life may prove difficult. Researchers have been
fascinated with Enceladus since July 2005, when Cassini revealed
a dramatic plume of ice particles and water vapour shooting out
from the moon's south pole. The plume's origin is still being
debated, but some models suggest the moon holds an ocean of
liquid water beneath its surface. This ocean could be a
potential habitat for extraterrestrial life. Now, a team led by
Christopher McKay of NASA's Ames Research Center in Moffett
Field, California, says Cassini could offer up the first
evidence that life exists or once existed on the 500 km-wide
moon. Though the probe was never designed to look for life, it
could do so by studying organic chemicals such as methane in the
plume, the team says. "If you think about what you need for
life, you need water, energy, organic m