Posted on 09/08/2005 4:46:27 AM PDT by PatrickHenry
Saturn's tiny moon Enceladus is "absolutely a highlight" of the Cassini mission and should be targeted in future searches for life, Robert H. Brown of The University of Arizona, leader of the Cassini visual and infrared mapping spectrometer team, said last week.
Brown and other Cassini scientists attended a meeting in London last week and are at the 37th annual Division of Planetary Sciences meeting at Cambridge University this week.
"Enceladus is without a doubt one of the most spectacular things Cassini has seen," Brown said in a phone interview Thursday. "It's one of the biggest puzzles. It'll be a long time before anyone comes up with a good explanation of how Enceladus does what it does, and for a scientist, that's pure, unmitigated fun. Solving the biggest puzzles is the thrilling part of doing science."
Scientists got their first glimpse of Enceladus's geology when Voyager 2 flew by the icy bright satellite in August 1981. They were completely baffled. Voyager photographed areas of young, smooth terrain that told them that the moon must have been geologically active as late as 100 million years ago.
But nothing explained how tiny Enceladus -- only 314 miles across -- could get hot enough to melt. It seemingly doesn't have enough interior rocks for radioactive heating, an eccentric enough orbit for tidal heating, or enough ammonia to lower its melting temperature. After Voyager, researchers shelved Enceladus as an unsolvable problem for a while.
This year, Cassini turned its more powerful cameras and instruments on Enceladus during Feb. 17, March 9 and July 14 flybys. Results have stunned and delighted.
The diminutive moon turns out to have a primarily water vapor atmosphere tinged with nitrogen, carbon dioxide and other simple carbon-based molecules (organics) concentrated at its south pole. Its south pole is a hotspot, hovering at a relatively balmy minus -183 degrees Celsius compared to the expected temperature of -203 degrees Celsius.
Enceladus's south pole is a hotbed of geological action. The south pole region is cut by parallel cracks roughly 81 miles long and 25 miles apart. The cracks, dubbed "tiger stripes," vent vapor and fine ice water particles that have crystallized on Enceladus's surface as recently as 1,000 years to 10 years ago. The fine ice material is probably the major source of particles that replenish Saturn's outermost ring, its E ring.
"The kind of geophysical activity we see is quite likely being driven by liquid water below the surface," Brown said. Cassini hasn't seen ice geysers or ice volcanoes, but the lack of ammonia, and the sheer volume of water vapor escaping suggests there's pure-water volcanism on Enceladus, he added.
"We detected simple organics in the tiger stripes," Brown said. The simple organics include carbon dioxide and hydrogen-and-carbon-containing molecules like methane, ethane and ethylene. "Methane (basically natural gas) has probably been locked up inside Enceladus since the solar system formed and is now bubbling up through the vents."
The visual and infrared mapping spectrometer can't detect nitrogen, but Cassini's ion neutral mass spectrometer may have found nitrogen in Enceladus's atmosphere. All other results from these two very different instruments are entirely consistent, which gives Cassini mission scientists confidence in their results, Brown said.
"So you've got subsurface liquid water, simple organics and water vapor welling up from below. Over time -- and Enceladus has been around 4.5 billion years, just like Earth and the rest of the solar system -- heating a cocktail of simple organics, water and nitrogen could form some of the most basic building blocks of life," Brown said. "Whether that's happened at Enceladus is not clear, but Enceladus, much like Jupiter's moon Europa and the planet Mars, now has to be a place where we eventually search for life."
The $3.2 billion Cassini-Huygens mission is a joint venture between the NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington.
We could ask it to take us to its leader.
Heh, asking is for more sensitive species.
We *demand* to see the leader of the mold!
...or, give them a 4 day package to Orlando's Disney World resort. All the mold would have to do is come in for a 90 minute seminar on time share opportunities.
For Enceladus NASA's protocol is similar but simpler. They're gonna add some croutons and ranch dressing to enceladus and weight for a low carb reaction!
More speculation here: http://www.thunderbolts.info/tpod/2005/arch05/00current.htm
Don't you think Venus is just too damn hot?
Plasmodial Slime Mold alert.
Balmy! I'll pack the shorts and t-shirts when I go.
(article): The diminutive moon turns out to have a primarily water vapor atmosphere
It's not the heat, it's the humidity that'll kill ya!
I say we make a whole bunch of small probe-bots that'll use those ion continuous-thrust engines to go out, attach themselves to Ceres, and have them slam it into Venus. The water oughta cool down Venus and the impact oughta get rid of a whole bunch of the sulfur dioxide.
Yeah, if you don't take the time to understand the theory, it does take a lot of faith.
Why does discussion of lifeforms on other planets bring out the C/E debaters? Seems like there either is life out there or there isn't. One thing seems likely: there will be life out there and it will be us.
Thanks for the ping!
Tew kewl :)
Acidic clouds of Venus could harbour life
Venus is usually written off as a potential haven for life because of its hellishly hot and acidic surface. But conditions in the atmosphere at an altitude of around 50 kilometres are relatively hospitable: the temperature is about 70 °C, with a pressure of about one atmosphere.
Although the clouds are very acidic, this region also has the highest concentration of water droplets in the Venusian atmosphere. "From an astrobiology point of view, Venus is not hopeless," says Dirk Schulze-Makuch from the University of Texas at El Paso.
...cut...
Even more mysterious is the presence of carbonyl sulphide. This gas is so difficult to produce inorganically that it is sometimes considered an unambiguous indicator of biological activity.
I personally believe (and yes this is a belief) that life is replete throughout the universe.
The presence of organic molecules in interstellar dust clouds would suggest that life has a good chance of getting started wherever there is a favorable environment -- one that remains favorable long enough. And it now appears that stars with planets are plentiful. We can't be the only world with liquid water where life can develop. The big question -- and you know this better than I do -- is not whether there's life out there, but how often life gets the opportunity to develop past the stage of lichens, mosses, etc.
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