for National Geographic News
One of the places in the solar system most likely to have extraterrestrial life may have gotten off to a hot, highly radioactive start, scientists reported yesterday at a meeting in Houston, Texas.
Enceladus, a moon of Saturn, stunned scientists two years ago when NASA's Cassini orbiter discovered geyser-like jets of water vapor shooting into space from its south pole.
(Read: "Saturn Moon Has Water Geysers and, Just Maybe, Life" [March 10, 2006].)
Now a new study of Enceladus's plume finds that it's rich in nitrogen gas.
"This is interesting, because nitrogen is hard to produce in a body as small as Enceladus without significant heat," said John Spencer, a planetary scientist with the Southwest Research Institute in Boulder, Colorado. Spencer who was not part of the study.
The find suggests that the moon's core once reached temperatures around 1,070 degrees Fahrenheit (577 degrees Celsius)—hot enough to convert Enceladus's internal stores of ammonia into nitrogen.
This may also be hot enough to produce the possible precursors for life, said the study's lead author, Dennis Matson of the Jet Propulsion Laboratory (JPL) in Pasadena, California.
"We've got an organic brew, a heat source, and liquid water—all key ingredients for life," Matson said in a press statement.
"And while no one is claiming that we have found life, by any means, we probably have evidence for a place that might be hospitable to life."
Cassini scientist Carolyn Porco of the Space Science Institute in Boulder, Colorado, said Enceladus should be a leading candidate site for future probes in search of extraterrestrial life.
"I think that if there is liquid water there, then Enceladus is the next 'go-to' place in the solar system."
(See an interactive map of the solar system.)
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