This story was updated at 3:30 p.m. ET.
A sniff test of water vapor
spewing from Saturn's moon Enceladus shows it is gushing with organic
molecules, increasing the possibility of life existing somewhere in the Saturn
system.
Scientists have been
intrigued by the moon since the
fountain of water was first spotted in 2005. Now they've identified a soup of prebiotic material there, similar to what's found in comets, from an analysis of data collected by the Cassini spacecraft.
Nobody really knows how
life began, but astrobiologists guess it required chemicals like those tasted
by Cassini, a little liquid water and some unknown spark.
Hunter Waite, a Cassini principal
investigator at the Southwest Research Institute (SWRI) in San Antonio, said
Enceladus' newly understood composition should stir up previous notions of
Saturn and its moons.
"These findings will
definitely get people to ask new questions about the formation of the Saturn
system," Wait told SPACE.com. "The astrobiological potential
of the Saturn system just went up a notch or two."
Cassini made
its observations during a high-speed
pass 30 miles (48 km) above Enceladus on March 12, and recorded the highest temperatures yet
detected near tiger stripe-like fissures on the icy moon's southern pole.
Waite and other scientists
released their early findings about Enceladus' thermal activity and icy plume
composition during a briefing today at NASA headquarters in Washington, D.C.
Big comet?
The new heat maps of
Enceladus' surface show temperatures higher than previously observed in the
south polar region, with hot tracks running the length of giant fissures.
"They're still awfully
cold, but much warmer than background temperatures of the rest of the
surface," said John Spencer, a Cassini scientist at SWRI in Boulder, Colo. "This means it has to be even warmer under the surface and raises the
possibility of liquid water beneath the [exterior]."
Cassini measured the fissures
to be -135 degrees Fahrenheit (-93 degrees Celsius) near their centers. That's
about 63 degrees F warmer than previously observed and some 200 degrees F (111
degrees C) warmer than the rest of the moon's surface.
Scientists also say Cassini
sampled organic chemicals during its bath in the icy jets and that they are
similar to those found in comets.
"A completely
unexpected surprise is that the chemistry of Enceladus, what's coming out from
inside, resembles that of a comet," Waite said, but noted that Enceladus
is also very different from a comet. "Comets have tails and orbit the sun,
and Enceladus' activity is powered by internal heat while comet activity is
powered by sunlight."
Organic steam bath
In addition to carbon
dioxide, carbon monoxide and other compounds, Waite said organic molecules such
as methane, propane, acetylene and formaldehyde were sniffed in Enceladus' icy
plumes.
"Enceladus' brew is
like carbonated water with an essence of natural gas," Waite said of the
moon's steamy jets. "Astrobiologically speaking, this moon is one
of the most interesting places in the solar system."
Dennis Matson, Cassini
project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said all of the ingredients for life could be present beneath Enceladus' pockmarked
surface.
"Enceladus has got
warmth, water and organic chemicals," said Dennis Matson. "These
three basic ingredients provide a minimum for the origin of life."
But Matson said Cassini
will have to gather more data before a key element — liquid water —
can be verified to exist on the moon.
"We ... [can't tell]
whether the interior of Enceladus contains liquid water and if that water might
be a habitat for life," Matson said during today's briefing, "but these are the questions
that Cassini will focus on in future flybys."
The spacecraft is set to
revisit Enceladus in August and October of this year, followed by five more flybys
in the next two years.
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