| Topic: |
Religions > Atheism |
| User: |
"stoney" |
| Date: |
09 Mar 2006 01:14:24 PM |
| Object: |
Liquid water on Saturn moon could support life |
http://www.msnbc.msn.com/id/11736311/
Liquid water on Saturn moon could support life
Cassini spacecraft sees signs of geysers on icy Enceladus
By Alan Boyle
Science editor
MSNBC
Updated: 1:39 p.m. ET March 9, 2006
Scientists have found evidence that cold, Yellowstone-like geysers of
water are issuing from a moon of Saturn called Enceladus, apparently
fueled by liquid reservoirs that may lie just tens of yards beneath the
moon's icy surface.
The surprising discovery, detailed in Friday's issue of the journal
Science, could shoot Enceladus to the top of the list in the search for
life elsewhere in our solar system. Scientists described it as the most
important discovery in planetary science in a quarter-century.
"I think this is important enough that we will see a redirection in the
planetary exploration program," Carolyn Porco, head of the imaging team
for the Cassini mission to Saturn, told MSNBC.com. "We've just brought
Enceladus up to the forefront as a major target of astrobiological
interest."
The readings from Enceladus' geyser plumes indicate that all the
prerequisites for life as we know it could exist beneath Enceladus'
surface, Porco said.
"Living organisms require liquid water and organic materials, and we
know we have both on Enceladus now," she said. "The plumes through which
Cassini flew last July contain methane, contain CO2, propane — they
contain several organic materials."
The third necessary ingredient — energy for fueling life's processes —
could exist around hydrothermal vents around the bottom of Enceladus'
water reservoirs, just as it does around Earth's deep-ocean hydrothermal
vents.
The results impressed University of Colorado planetary scientist Robert
Pappalardo, who has studied Enceladus and other icy moons but was not
involved in the newly published research.
"I think the discovery of activity on Enceladus is about the most
exciting discovery in planetary science since the volcanoes of Io," he
said, referring to the detection of volcanic activity on Jupiter's moon
by the Voyager probe in 1979.
The findings unveiled Thursday are based on imagery as well as
temperature readings from Cassini, a U.S-European spacecraft that has
been studying the ringed planet and its moons since 2004.
The precise sources of geysers could not be spotted directly, because
Cassini's camera isn't quite good enough to spot the bright spray of
water and ice crystals against the bright ice on Enceladus' surface,
said imaging team member Andrew Ingersoll, an atmospheric scientist at
the California Institute of Technology.
However, Cassini's camera repeatedly recorded the spray of ice crystals
and water vapor from Enceladus' south polar region, backlit by sunlight.
That imagery allowed researchers to trace the source back to the
mysterious dark "tiger stripes" previously seen on Enceladus.
A detailed analysis of the spray led researchers to throw out several
possibilities for its origin, including the idea that the geysers'
contents were pure ice or a cometlike slurry of ice and dirt.
The Cassini team found that the spray from the geysers was composed of
equal proportions of ice and water vapor. That ruled out the "pure ice"
model as well as the "comet" model, Porco said. The best remaining model
was that the geyser was driven by liquid water beneath the surface.
"We arrived at our last model, and in some ways somewhat reluctantly,
because this is a pretty extraordinary result," she said. "Like [the
late astronomer] Carl Sagan was fond of saying, 'Extraordinary claims
require extraordinary evidence.'"
The imaging team's conclusion was supported by the temperature readings
from Cassini's infrared spectrometer: Although the surface temperatures
are far below freezing, the readings showed relatively warm spots in the
south polar region, centering on dark cracks that have been nicknamed
"tiger stripes." Scientists traced the internal heating patterns that
could create such warm spots on the surface ice, and concluded that
temperatures could be above freezing mere yards few yards beneath the
surface.
"It can be warm enough 10 meters or so beneath the surface," Porco
explained, "and there's enough pressure to keep liquid water stable at
that depth."
Still more supporting evidence came from an analysis of the ice
surrounding the "tiger stripe" cracks. That ice was amorphous and
virtually crater-free, indicating that it welled up relatively recently.
Cassini's images showed that the geysers rose hundreds of miles above
the surface. Based on the imagery, researchers concluded that most of
the ice crystals fell back to the surface as snow, but some of the ice
escaped Enceladus' gravity field and became part of a wide, thin ring of
Saturn.
Boiling water beneath the surface?
The Cassini team theorized that water could be heated to the boiling
point far beneath the surface, pushing up through the "tiger stripe"
cracks, she said. The source of the heating could be molten rock,
perhaps extending nearer to the surface in the south pole region, she
said.
"If you have molten rock, then we really are playing the game of looking
possibly at an environment that is conducive to living organisms," Porco
said. "If this is correct, we've just hit the ball out of the park. It
doesn't really get much more exciting than this. If this is all we did
on Cassini, this would have made the mission worthwhile."
The types of living organisms Porco and astrobiologists have in mind
aren't little green men or even little green fish. Rather, they're more
likely to be microbes that have adapted to the type of sunless,
chemical-fueled environment seen around Earth's hydrothermal vents. For
years, scientists have theorized that such environments might exist
beneath the similarly icy surface of Europa, a moon of Jupiter, or
beneath the surface soil of Mars.
Years of further research
It will literally take years to follow up on Cassini's findings about
Enceladus: Although the spacecraft made three close flybys of the moon
in 2005, the next close encounter isn't scheduled until 2008. Porco said
the Cassini team is already working to change the probe's orbit to get
closer to the moon, and she said it would be imperative for the Cassini
mission to get an extension beyond 2008 for even more encounters.
"It would be insanity to think that we wouldn't get it, based on this
discovery," she said.
Ingersoll said observations need to be repeated to solidify the case for
liquid water on Enceladus. "I'd be perfectly happy to do this again,
just to see how much variability there is," he said.
One of the big unanswered questions has to do with why so much heat is
emanating from such a little moon. On Europa, the heat is thought to be
generated by a molten core as well as tidal flexing — but on Enceladus,
the calculations for such effects fall short by a factor of 10, Porco
said.
Some scientists have theorized that Enceladus is an asymmetric moon,
with a small molten core that's off-center. That could explain why the
warm spots are concentrated in the south polar region, and why Enceladus
might have regional reservoirs of liquid water rather than a global
subsurface ocean. However, scientists would have to explain how the core
came to be off-center in the first place.
New scientific frontiers
Pappalardo said the research related to Enceladus' geysers suggested
many more scientific questions yet to be answered.
"I think it certainly elevates the priority of further Enceladus
exploration, by the Cassini spacecraft first off," he said. "We really
need to understand what's going on there. What kind of plumbing is there
on Enceladus? What could be maintaining the liquid, if there really is a
reservoir of liquid water within?"
Like Pappalardo, Brown University planetary scientist James Head ranked
the results from Enceladus alongside the 1979 discovery of Io's
volcanoes. Head, an expert on Europa, said the findings could help
reverse NASA cutbacks in space science missions. For example, NASA
recently put a proposed mission to Europa and Jupiter's other icy moons
on hold.
"People are really striving to try to reverse that, because it is such a
clear imperative," he told MSNBC.com.
Porco said that the evidence for liquid water could well put Enceladus
ahead of Europa as a priority for further exploration, but Head said one
icy moon shouldn't be pitted against another.
"These are the kinds of exciting results that exploration is all about,"
he said. "I wouldn’t say it would change the ranking on Europa vs.
Enceladus. What it really says that we need to get off our butts and
explore Europa — because the same kind of exploration is going to give
us hundreds of insights about comparable things."
© 2006 MSNBC
--
Fundies and trolls are cordially invited to
shove a wooden cross up their arses and rotate
at a high rate of speed. I trust you'll
be 'blessed' with a cornucopia of splinters.
.
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| User: "Neil Kelsey" |
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| Title: Re: Liquid water on Saturn moon could support life |
10 Mar 2006 06:15:39 PM |
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Um, are you at all familiar with Cassini? The discover of the geysers
on Enceladus was serendipitous. Just the discovery of the sulfur
volcanoes on Io was a happy accident. We send out probes not
expecting anything. We are constantly amazed at the wonders we find.
Why are you so afraid of us finding that life is found elsewhere in
the solar system?
That's a good question...why ARE they so afraid? I think it would drive
another nail into the coffin of religion, but hell, I've thought that
with other things, like evolution, and that doesn't even seem to make
them blink. Maybe they're afraid aliens would have the terrifying proof
that there's no "God?" Someone explain this to me.
.
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| User: "stoney" |
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| Title: Re: Liquid water on Saturn moon could support life |
11 Mar 2006 08:13:20 PM |
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On 10 Mar 2006 16:15:39 -0800, "Neil Kelsey" <neil_kelsey@hotmail.com>
wrote in alt.atheism
Um, are you at all familiar with Cassini? The discover of the geysers
on Enceladus was serendipitous. Just the discovery of the sulfur
volcanoes on Io was a happy accident. We send out probes not
expecting anything. We are constantly amazed at the wonders we find.
Why are you so afraid of us finding that life is found elsewhere in
the solar system?
That's a good question...why ARE they so afraid? I think it would drive
another nail into the coffin of religion, but hell, I've thought that
with other things, like evolution, and that doesn't even seem to make
them blink. Maybe they're afraid aliens would have the terrifying proof
that there's no "God?" Someone explain this to me.
Pure unadultrated jealousy, fear, and envy on their parts.
--
Fundies and trolls are cordially invited to
shove a wooden cross up their arses and rotate
at a high rate of speed. I trust you'll
be 'blessed' with a cornucopia of splinters.
.
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