If space travelers ever visit Saturn's largest moon, they will find a tropical world where temperatures plunge to minus 274 degrees Fahrenheit, methane rains from the sky and dunes of ice or tar cover the planet's most arid regions. These conditions reflect a cold mirror image of Earth's tropical climate, according to scientists at the University of Chicago.

"You have all these things that are analogous to Earth. At the same time, it's foreign and unfamiliar," said Ray Pierrehumbert, the Louis Block Professor in Geophysical Sciences at Chicago.

Titan, one of Saturn's 60 moons, is the only moon in the solar system large enough to support an atmosphere. Pierrehumbert and Jonathan Mitchell, who recently completed his Ph.D. in Astronomy & Astrophysics at Chicago, have been comparing observations of Titan collected by the Cassini space probe and the Hubble Space Telescope with their own computer simulations of the moon's atmosphere.

Their study of the dynamics behind Titan's methane clouds have appeared in the Proceedings of the National Academy of Sciences. Their continuing research on Titan's climate focuses on the moon's deserts.

"One of the things that attracts me about Titan is that it has a lot of the same circulation features as Earth, but done with completely different substances that work at different temperatures," Pierrehumbert said. On Earth, for example, water forms liquid and is relatively active as a vapor in the atmosphere. But on Titan, water is a rock.

"It's not more volatile on Titan than sand is on Earth."

Methane-natural gas-assumes an Earthlike role of water on Titan. It exists in enough abundance to condense into rain and form puddles on the surface within the range of temperatures that occur on Titan.

"The ironic thing on Titan is that although it's much colder than Earth, it actually acts like a super-hot Earth rather than a snowball Earth, because at Titan temperatures, methane is more volatile than water vapor is at Earth temperatures," Pierrehumbert said.

Pierrehumbert and Mitchell even go so far as to call Titan's climate tropical, even though it sounds odd for a moon that orbits Saturn more than nine times farther from the sun than Earth. Along with the behavior of methane, Titan's slow rotation rate also contributes to its tropical nature. Earth's tropical weather systems extend only to plus or minus 30 degrees of latitude from the equator. But on Titan, which rotates only once every 16 days, "the tropical weather system extends to the entire planet," Pierrehumbert said.

Titan's tropical nature means that scientists can observe the behavior of its clouds using theories they've relied upon to understand Earth's tropics, Mitchell noted.Titan's atmosphere produces an updraft where surface winds converge. This updraft lifts evaporated methane up to cooler temperatures and lower pressures, where much of it condenses and forms clouds.

"This is a well-known feature on Earth called an ITCZ, the inter-tropical convergence zone," Mitchell said. Earth's oceans help confine the ITCZ to the lowest latitudes. But in some scenarios for oceanless Titan, the ITCZ in Mitchell's computer simulations wanders in latitude almost from one pole to the other. Titan's clouds should also follow the ITCZ.

Titan's orange atmospheric haze complicates efforts to observe the moon's clouds. "This haze shrouds the entire surface," Mitchell said. "It pretty much blocks all visible light from reaching us from the surface or from the lower atmosphere."

Nevertheless, infrared observations via two narrow frequency bands have recently revealed that clouds are currently confined to the moon's southern hemisphere, which is just now emerging from its summer season.

"There should be a very large seasonality in these cloud features," Mitchell said. "Cassini and other instruments might be able to tell us about that in the next seven to 10 years or so, as the seasons progress."

Mitchell and Pierrehumbert's next paper will describe how oscillations in Titan's atmospheric circulation dry out the moon's midsection. Over the course of a year, Mitchell explained, "this oscillation in the atmosphere tends to transport moisture, or evaporated methane, out of the low latitudes and then deposit it at mid and high latitude in the form of rainfall. This is interesting, because recent Cassini observations of the surface suggest that the low latitudes are very dry."

Cassini images show dunes of ice or tar covering these low-latitude regions that correspond to the tropics on Earth. When ultraviolet light from the sun interacts with methane high in Titan's atmosphere, it creates byproducts such as ethane and hydrogen.

These byproducts become linked to chains of hydrocarbon molecules that create Titan's orange haze. When these molecules coalesce into large particles, they settle out as a tar-like rain.

"Titan is like a big petrochemical plant," Pierrehumbert said. "Although this is all happening at a much lower temperature than in a petroleum refinery, the basic processes going on there are very closely allied to what people do when they make fuel."

So no one interested in the moon of Titan and its atmosphere that can relate to some things like Earth? Wow fascinating

<- IS interested but I don't anything intelligent to say on the matter. I would that that its interesting how Titan witch look so foreign have weather pattern like that of Earth. There are some scientists that believe that they maybe primitive life on Titan and now that we know some of its weather cycles it may be able to help find the answer to the question.

Wow that would be amazing actually. I mean it is said on the ice sheets of Mars we might find samples of somekind of life that once existed on this planet. That would be interesting to witness one day if they manage to land on that exact spot and take some samples. Even if it is only microscopic simple organisms.

Tell Shell, BP, and Chevron they need to get together and figure out a way to transport all them hydrocarbons back.

Actually it's funny that you talk about life on titan b/c if it is natural gas in the atmosphere, natural gas forms on earth from decayed ex-living organisms. I haven't looked into the matter in too much depth but I think methane can be formed by other means, but might be interesting to find out. Plus if we can get natural gas from one of the biggest moons in the SS (if not the biggest) and it's covered with the stuff we'll have plenty of energy to live off of until we can get alternative fuel worked out a little better (just got done looking at the price of windpower setup vs the rewards, not promising).

Then we get to be the evil aliens from the sci-fi movies that roam around collecting resources from other planets.... Yay!

Brilliant ideas actually. If only we can get such cargo ships to fly to these locations and collect

Now I am thinking Battlestar Galactica aren't I

I LOVE Battlestar Galactica Awesome Awesome show

I personally like the old episodes best, yet I know alot who enjoy the newest ones also.

I also enjoyed Buck Rogers

I like the old and new series but the new series really broke new ground in sci fi as far as I am concerned. Have you seen the entire series. i have every episode recorded old and new series and watched them hundreds of times

I watched the old series as a teenager, but the new series I only watched a few times on the SciFi channel. I think I should watch it from the beginning. Maybe then I can enjoy it better. It seems much more drama is involved and less action.

Watch for a fantasy write later today on your Titan
Got me thinking...

Looking forward to it and if you want to participate in a medieval fantasy adventure that allows you to exploit your imagination with others then don't hesitate to contact me or read my profile for more information.

just remember if you are in astronomy class

and the question is name a moon of saturn

remember the titan

great movie by the way

basically. the new series had more mystery to it as well

Amazing ain't it that we have all that out there. (and the technology to go get it) and we are still fighting over the same silly piece of desert that Cain slew Able for.

Perhaps the human race is not ready to live.

Something just hit Jupiter


Russian Space Officials are reporting in the Kremlin today that the meteor-strike on the Planet Jupiter yesterday is “cause for alarm” over what these reports say is an “unusual and growing” gravitational “influence” appearing to have been generated from the extremely rare triple conjunction of Jupiter, Neptune and Chiron which is “severely altering” the paths of space debris originating in the Ort Cloud and heading towards the inner Planets of our Solar System, including Earth.

Further being stated in these reports is that the paths of numerous meteors and asteroids are about to be further altered towards our Earth when on July 22nd the Solar Eclipse, the longest to occur in the entire 21st Century, will lesson our Planets gravitational field as evidence from the newly launched Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite is now showing.

Most interesting to note in these reports is that the possible end-of-July timeline should our Earth be hit by an errant meteorite exactly coincides with the United States announcing what they are calling a Tier 1 National Level Exercise to be held on July 27 through July 31 by their Federal Emergency Management Agency (FEMA) who is advising all of their citizens to prepare for at least 3-days by storing food and water.

So a huge black hole on Jupiter the size of Earth and not one is surprised or interested? Some say it was somekind of meteroid.

Amazing I say! Just amazing that no comments come from that

It not titan I find interesting...

Its the one with the 'primordial soup'... Such a world could spring forth life under the right conditions.

(gods backup plan?)

I though we where talking about titian? But yea that was scary, what if that asteroid was coming for use we wouldn't even know about it until it was too late. The most interesting thing was that it was discover by a amateur astronomer.



That is Titian

After the fall of man...

God: well at least I have Titian...

*God see humans colonizing Titian*

God: well crap...