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Eikþyrnir
Saturday, December 18th, 2004, 11:04 AM
Titan clouds seen to come and go

Scientists now have their first direct evidence of changing weather patterns on Titan, Saturn's largest moon.

When the Cassini spacecraft flew past the satellite on Monday it spied clouds at mid-latitudes that were not present on its last flyby in October.

The observations will allow researchers to investigate atmospheric dynamics on Titan, the only moon in the Solar System with a thick covering of gas.

The results came out at the American Geophysical Union's (AGU) Fall Meeting.

"We see for the first time discrete cloud features at mid-latitudes, which means we see direct evidence of weather, and we can get wind speeds and atmospheric circulation over a region we hadn't been able to measure before," said Dr Kevin Baines, from the US space agency's (Nasa) Jet Propulsion Laboratory.

Cassini also saw banding and layering in the moon's upper atmosphere.

Moons apart

In addition, mission scientists took the opportunity at the meeting to share images of Dione, one of Saturn's smaller icy moons, which Cassini passed at a distance of 81,400km (50,600 miles) on Tuesday.

These pictures are the most detailed since the Voyager 1 probe returned pictures of the 1,120km-wide (695 miles) satellite in 1980.

They revealed large surface cracks and bright ice cliffs where scientists thought they would see thick ice deposits.

"This is one of the most surprising results so far. It just wasn't what we expected," said the Cassini imaging team leader, Dr Carolyn Porco.

But if Dione has been a revelation, Titan remains an enigma.

With its thick nitrogen-rich atmosphere and photochemical smog, surface features are obscured from visible inspection.

Cassini has to use its multi-wavelength instruments to pierce the shroud, but, even so, scientists are still struggling to interpret the dark and bright areas detected.

Because of its chemistry and temperature, many suspect the satellite harbours vast regions of oily sludge that overlie ice-rock. It is possible, also, that there are moving oceans of liquid hydrocarbons, such as ethane and methane.

Up and down

Whether the dark areas mark out the extent of such seas, no-one seems quite sure. The bright areas could conceivably be the hydrocarbon zones, scientists concede.

"This week has been the tale of two moons," said Dr Porco.
"One of them has been like out of a Lewis Carroll story and gets curiouser and curiouser the more we look at it and the closer we get, and the other turns out to be gloriously clear and has given us what I consider to be one of our most surprising results so far with very little effort," she told the AGU meeting.

The true nature of Titan's surface will only become apparent as Cassini conducts more flybys and obtains some radar altimetry data which will indicate heights.

"At the moment, we don't know up from down; we don't know if dark is low-lying or if bright is high," emphasised Dr Porco.

An important contribution, too, will come from the Huygens probe, currently attached to Cassini, but soon to be ejected to take direct measurements of Titan's environment.

Collision course

Mission scientists told the AGU that the engineering model of the moon's atmosphere chimed with recent observations.

"It all looked good. The conclusion is that we can proceed to the next step," said Jean-Pierre Lebreton, the Huygens project manager. "We got the green light."

Engineers are confident Huygen's three-parachute descent system will open at the correct moments to give a gentle drift down to the surface.

"They have also now corrected Cassini's trajectory through the Saturnian system to put it on a crash course with Titan," Dr Lebreton explained.

"This has to be so because when Huygens is released it will have no manoeuvring capability and, so, Cassini has to put it on a collision course with Titan for 14 January."

Cassini, though, will be in no danger. It will execute another course correction after releasing Huygens to make sure it passes Titan at a safe distance and is able to relay the small probe's scientific data back to Earth.

The Cassini-Huygens mission is a co-operative mission between the US space agency Nasa, the European Space Agency (Esa) and the Italian Space Agency (Asi).

Story - Pictures Included (http://news.bbc.co.uk/2/hi/science/nature/4104597.stm)

Blutwölfin
Saturday, March 18th, 2006, 01:56 PM
Earth could seed Titan with life

Terrestrial rocks blown into space by asteroid impacts on Earth could have taken life to Saturn's moon Titan, scientists have announced.

Earth microbes in these meteorites could have seeded the organic-rich world with life, scientists believe.

They think the impact on Earth that killed off the dinosaurs could have ejected enough material for some to reach far-off moons like Titan.


Read more (http://news.bbc.co.uk/2/hi/science/nature/4819370.stm)

Gorm the Old
Saturday, March 18th, 2006, 03:35 PM
Yes, this is certainly possible. My reaction to this possibility, however, is, with a shrug of the shoulders, "So what ?"

Ewergrin
Saturday, March 18th, 2006, 03:56 PM
Will the Sirens of Titan be there to greet me when I get there, I wonder?

Siegfried
Saturday, March 18th, 2006, 04:39 PM
Yes, this is certainly possible. My reaction to this possibility, however, is, with a shrug of the shoulders, "So what ?"

Perhaps we could learn something about evolution if we could study such microbes? :)

The Horned God
Sunday, March 19th, 2006, 03:50 AM
One of the problems for Earth like microbes on
Titan would be the extreme cold which would slow chemical reactions and therefore life processes down almost to a stand-still, however it has been proposed that some "life as we know it" might survive around volcanic vents on Titan.

Another theory is that Titan might possess quite different life chemistry with Methane which is liquid on the surface of the moon taking the place occupied by water in our ecosystem.




'Catastrophic rains'

It takes a relatively long time for methane to build up to a point where it can rain down on Titan's surface. Scientists, therefore, think rains are only occasional, but catastrophic, when they occur.

Evidence also suggests Titan is constantly being resurfaced by a fluid mixture of water and ammonia spewed out by volcanoes and hot springs, explaining why Titan is not littered with impact craters like its neighbours


Many processes that occur on Earth also take place on Titan
A surface feature called Ganesa Macula may show just such a flow emanating from a volcanic crater.

The moon's icy surface is also covered with a film, or patina, of organic compounds, Cassini-Huygens data shows.

One researcher has even proposed a way for life to survive on the giant Saturnian satellite. It is too cold for organisms to survive on the surface of Titan, where temperatures are about -178C (-289F).

But David Grinspoon, of the Southwest Research Institute, US, says organisms could occupy specific niches, such as hot springs. They could use acetylene, in reaction with hydrogen gas, to release enough energy to power metabolism, and possibly to heat their environments.

Source (http://news.bbc.co.uk/1/hi/sci/tech/4229110.stm)

norskdeutschami
Thursday, August 24th, 2006, 05:46 AM
That's a beautiful concept, however as much as I'd like to believe the claim, the chance is probably low at best. :~(

What is the possibility that the microbes could have actually survived the journey through the vacuum of space, not to mention the extremely cold temperatures? I must admit the chance is indeed there, and occassionally that very slim chance does shine through. However I'm almost more apt to believe the notion that there may be microbian life on Io (a sattelite of Jupiter) due to volcanic activity and a surprizing claim that there is also a possibility of water on Io as well (open issue).

Have you heard this as well? A great in detail description of Io can be found here:
http://www.nineplanets.org/io.html :thumbup

Orlon
Monday, October 9th, 2006, 11:03 PM
Titan has a dense atmosphere consisting of 98 percent nitrogen and the rest mostly methane. Temperature hovers around 95K (-178 C). Thats pretty cold, to say the least. Even if some eartly organisms could survive without suffering ice chrystal damage to the cell membranes, the reducing atmosphere would be useless to most of them.

Problem is, there is nothing to eat. And by "eat" I dont mean food, but chemical processes the bacteria/archean could use to aquire chemical energy. Some sulfur eating archean (sp?) perhaps could survive in hot volcanic springs (after all, the moon has water), but then comes the problem of the hypotetical meteorite actually getting there, falling down trough an atmosphere and hitting a surface is one thing, but hitting something that is likely sealed of from surface? No, that won't happen.

Io is both extremely volcanic, dry and sterilized by Jupiters radiation belts, so that one is probably one of the least likely places in the solar system to find life.

I'd say the most likely place to find life outside of earth is Mars, likely surviving bacteria from wetter times or earth seeded ones. Then Europa, where life could thrive on geothermal heat in the deep sea that's very likely to exist under the planets icy surface, well protected from the radiation belt by kilometres of water and ice.

Those shimp/jellyfish would be Europeans.

Dropkick
Tuesday, December 19th, 2006, 12:47 AM
Some say that DNA is formed frequently by nature by some sort of energy like an unknown magnetic energy.:|

Europa has oceans underneath it's surface so that for me would be the most interesting place to visit.

Rongoteus
Thursday, January 4th, 2007, 03:14 PM
Below Haze, Saturn’s Biggest Moon Has Lakes


By JOHN NOBLE WILFORD
Published: January 4, 2007

As scientists have predicted but have had a hard time proving, the surface of Titan, Saturn’s largest moon, appears to be dotted with lakes of liquid methane. The lakes are more intriguing evidence of the active phenomena at play on the only moon in the solar system with a dense atmosphere.

http://graphics10.nytimes.com/images/2007/01/03/science/03titan.500.jpg
NASA/JPL/USGS
A colorized radar image of Titan's surface. The colors are not a representation of what the human eye would see.


The discovery, reported yesterday by an international team of researchers, was made by a radar survey of Titan’s high northern latitudes by the Cassini spacecraft, which has been orbiting Saturn and its retinue of satellites since July 2004. One of the mission’s major objectives is the investigation of Titan’s environment, thought to be a frigid version of conditions on the primordial Earth.

The radar imaging system detected more than 75 dark patches in the landscape near Titan’s northern polar region, the scientists said in a detailed description of the find published today in the journal Nature.

The patches, they said, indicated smooth surfaces in an otherwise rugged topography, suggesting lake beds either partly dry or filled with liquid. These smooth surfaces, more or less circular and with diameters ranging from 2 miles to 40 miles, are associated with channels that appear to have been formed by flowing liquids, presumably tributaries to the lakes.

Methane exists in Titan’s atmosphere and, in the extreme cold of high latitudes, is expected to rain on the surface and be present as liquids in subsurface reservoirs.

The radar images, made on a close pass of Saturn’s largest moon by the Cassini spacecraft in July, “provide definitive evidence for the presence of lakes on the surface of Titan,” the discovery team concluded.

When the spacecraft conducted its first radar search above 70 degrees north latitude, Ellen R. Stofan, leader of the team, said in an interview, “We saw a huge swath of the surface just covered with lakes, like Minnesota.”

Dr. Stofan is a planetary scientist at Proxemy Research, a contractor in Virginia to the National Aeronautics and Space Administration, and also at University College London. Other team members include researchers at the Jet Propulsion Laboratory in Pasadena, Calif., which directs the Cassini mission; the University of Arizona; and several European institutions.

In an accompanying article in the journal, Christophe Sotin, a planetary scientist at the University of Nantes in France who was not involved in the research, wrote that the lakes and other mission findings were strong evidence that “methane on Titan plays the role of water on Earth.” It is the second-most abundant component of Titan’s atmosphere, after nitrogen.

The discovery, Dr. Sotin concluded, adds to the “weight of evidence” that processes on and beneath Titan’s surface must be similar to those dominating the early evolution of any Earth-like planet.

“As far as we know, there is only one planetary body that displays more dynamism than Titan,” he wrote. “Its name is Earth.”

Finding large bodies of liquid methane and probably ethane on Titan, in lakes or perhaps vast seas, had long been hypothesized, based on telescope observations of that moon’s smoggy methane-rich atmosphere and by the two Voyager spacecraft that passed close some 30 years ago. But the Cassini remote-sensing instruments had failed to detect an ocean, though they and the European Space Agency’s Huygens lander did find traces of the channels where liquids had apparently flowed across the surface.

On Cassini’s previous encounters with Titan, the smog-penetrating radar found no smaller liquid bodies, until it observed the region from 70 degrees north latitude to 83 degrees north latitude. At present, it is winter in Titan’s north. Methane is one of the few molecules to exist as a liquid in such cold conditions, scientists said, and is the most plausible explanation for the smooth, dark surfaces in the radar images.

Dr. Stofan said that the lake depressions could be volcanic craters or sinkholes; very few craters gouged out by meteorite impacts have been detected on Titan. Their roughly circular shapes and steep-sided rims are typical of volcanic depressions. Surface collapses, as in sinkholes, could fill the lakes with liquids from interior chambers, like aquifers on Earth.

In both cases, scientists said, methane vapor condensing and raining out of the cold Titan sky was probably a significant source of the liquid in the lakes.

Jonathan I. Lunine of the University of Arizona, another member of the discovery team, described in an interview what the lakes probably look like. The methane liquid would be transparent, enough to see the dark hydrocarbon sediments on the floor of shallow lakes. The liquid would be less viscous than water, perhaps like gasoline. Overhead, aerosols, minute particles in the upper atmosphere, presumably cast a dim orange light on the lake. In the dark of winter, one would need a flashlight to walk the shore.

Source (http://www.nytimes.com/2007/01/04/science/space/04titan.html?ref=science)

Liberator Germaniae
Wednesday, March 14th, 2007, 06:00 PM
Saturn's Icy Moon May Have Been Hot Enough for Life, Study Finds

Richard A. Lovett
for National Geographic News

March 13, 2007

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.

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."

But for now Cassini's next step is to pass through the geyser's plume, an encounter scheduled for March 2008.

Matson discussed his research at the annual Lunar and Planetary Science Conference. His findings will appear in the April issue of the journal Icarus.

Moon Had Hot Start

Scientists agree that Enceladus's jets indicate the moon's interior is hot, but how hot and why remain mysterious.

A theory unveiled at the conference suggests that the heat might have originated from the radioactive decay of aluminum and iron.

"Enceladus is a very small body, and it's made almost entirely of ice and rock," said Julie Castillo of JPL in a press release.

"The puzzle is how the moon developed a warm core."

The new theory posits that heat from the decay of radioactive elements softened the moon's interior. This allowed the pull of Saturn's gravity to flex the moon's hot core like a rubber ball—a process that could continue generating heat indefinitely.

Other scientists aren't convinced that radioactive materials were the source of the moon's internal heat.

"There are quite a lot of ideas being kicked around," said John Spencer of the Southwest Research Institute. "This is just one."

"[But] something had to kick-start Enceladus into [its present] state," he added.



Source (http://news.nationalgeographic.com/news/2007/03/070313-saturn-moon.html)