November 26, 2008

Evidence Of Liquid Water Found On Enceladus

A team of astronomers said on Thursday that supersonic plumes of gas and dust shooting off one of Saturn's moons suggest strong evidence of liquid water, a key building block of life.

The new discovery adds to the growing push to further explore the moon Enceladus, as some believe it is one of the solar system's most compelling places for potential life.

NASA astronomers estimated through images from the Cassini probe that the mysterious plumes shooting from Enceladus' icy terrain contained water vapor.

The team's findings support a theory that the plumes observed are caused by a water source deep inside Enceladus. Which is indeed a possibility considering that on earth, liquid water exists beneath ice at Lake Vostok, Antarctica.

The study's lead author, Candice Hansen of NASA's Jet Propulsion Lab in California, said new calculations suggest that the gas and dustspew at speeds faster-than-sound make a good case for liquid. Her team calculated the plumes travel more than 1,360 mph.

"Reaching that speed is hard to do without liquids," she said.

"There are only three places in the solar system we know or suspect to have liquid water near the surface," said UCF Assistant Professor Joshua Colwell. "Earth, Jupiter's moon Europa and now Saturn's Enceladus.

Hansen said her study simply provides more evidence building on what others have found and she acknowledged that her research is not the final proof of liquid water on Enceladus (pronounced en-SELL-ah-dus).

Planetary scientists Andrew Ingersoll at the California Institute of Technology said the research is good, but that it is possible to achieve such speeds with ice particles and at cooler temperatures.

Therefore, Ingersoll and other scientists agree that Hansen hasn't proven her case yet.

"The evidence in my mind is building on liquid water," said Carolyn Porco, the head of the Cassini camera team.

She agreed that Enceladus, one of 60 moons circling Saturn, has become the go-to place for exploration in the outer planets.

Many astronomers suggest that Europa, a moon of Jupiter, may have a liquid ocean beneath its frozen surface. But Hansen said Enceladus, thought to be responsible for producing one of Saturn's rings, is more accessible.

"Enceladus is sort of helpfully spewing out its innards," she said.

Hansen's research was published in the journal Nature.


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