Titanic Saturn

barakn writes "Using the Crab Nebula as an x-ray source, scientists have observed Titan's x-ray shadow to get a preliminary estimate of the extent of its outer atmosphere. On the same page, another article discusses the possibility that the hydrocarbon seas of Titan bear waves, albeit slow-moving and widely spaced, 7 times higher than waves on Earth (additional wave links here, here, and here). And Cassini-Huygens has snapped a photo of Saturn showing "two small, faint dark spots" in the southern hemisphere (this link has convenient arrows pointing at them, or here). Cassini-Huygens will achieve Saturn orbit insertion on July 1st. Huygens will detach and enter Titan's atmosphere in January, 2005."

Comments

A thick atmosphere in low gravity?

[Teckla]

Inquiring minds want to know: how does Titan keep its thick atmosphere in such low (15% of Earth) gravity?

-Teckla

Re:A thick atmosphere in low gravity?

[sploxx]

Yes, that's a good question. IANAPS (planetary scientist) but studying physics and should be able to give you a rough answer:
It's because titan is much farther away from the sun than earth and therefore much colder.

The point at which the loss of atmosphere becomes significant is when a sizeable amount of the atmosphere's molecules have escape velocity due to their temperature. Maybe mars lost it's atmosphere that way.

Try, e.g. "celestia" a free universe simulator to get a picture of the distances in the solar system.

Re:A thick atmosphere in low gravity?

[Anonymous Coward]

Inquiring minds want to know: how does Titan keep its thick atmosphere in such low (15% of Earth) gravity?

Titan is cold, its atmosphere's molecules slow and heavy.

It possibly was ejected in its formative phase containing a lot of volatile elements which replenish it as it goes.

It may participate in a gas torus cycle with Saturn where the atmosphere stripped by solar winds is fed into Saturn's orbit for potential later return to Titan.

Re:A thick atmosphere in low gravity?

[HeghmoH]

It's because of the gas torus effect. When atmosphere leaks away from Titan, it's still in roughly the same orbit about Saturn. When a lot of the atmosphere has leaked into that same orbit, it builds up and starts to form a torus of gas around Titan's orbit which helps keep the moon's atmosphere replenished. It's the presence of Saturn which allows this effect; rather than just getting blown into interstellar space like atmosphere escaping from, say, Mars does, it goes around Saturn and more or less comes back.

Re:A thick atmosphere in low gravity?

[CheshireCatCO]

I don't know who told you that, but that's totally wrong. There's no way a significant fraction of the atmosphere would ever be re-accreted by the planet from a torus, first of all. (Io has a very distinct torus and its atmosphere is all by non-existant.)

Second of all, we have yet to observe any Titan-torus, last I heard. (About two weeks ago, a comment made from one of the Cassini principle investigators.) If there's so much gas there, why can't we see it?

Finally, the reason Titan can hold a thick atmosphere is, as some already stated, because it's so bloody cold. You can do the simple atmospheric calculations and show that at the tempertures of Titan, it can hold that atmosphere pretty nicely.

A good place to look for details is _The New Solar System_, Beatty, Petersen, and Chaikin, editors.

Re:A thick atmosphere in low gravity?

[lab16]

Actually, IIRC, most astronomers now believe that the reason that mars doesn't have an atmosphere is because of a reverse runaway greenhouse effect.

Mars is just far enough away from the sun that the CO2 from its atmosphere started to condense into the rocks and water (which was present at the time this was happening), this caused the temperature to lower, causing more CO2 to go away, lowering the temp and so on.
This also explains why Venus has a thick hot atmosphere.
You can find more if you google for it.

"Titanic Saturn"

[pwroberts]

They'll discover icebergs up there next...

(Sorry!)

Re:"Titanic Saturn"

[black mariah]

Don't forget the hairstylists, consultants, and telephone sanitizers.

The Sirens of Titan

[CheeseburgerBlue]

1) Titan looks like a nice place for life to grow up. We're hoping to meet friends.

2) If we do meet friends, we're hoping they're sirens. I call the redhead.

Re:color me ignorant, but...

[Anonymous Coward]

Right, because bringing MORE hydrocarbons to Earth is EXACTLY what we want to do. Forget about the renewable energy resources that are already here. Let's import pollutants from another PLANET!

Re:color me ignorant, but...

[HeghmoH]

It depends on what you mean by "important".

If by "important", you mean "discovery of indicators of something I can either talk to or eat", it's not important. Almost certainly, nothing Cassini produces will be important according to that definition. You may as well stop paying attention now.

Re:color me ignorant, but...

[sploxx]

> Would somebody please explain to me why each of these things is important?

Because it's just interesting. That's all. People want to know. Why do you read post on slashdot? Probably because of the same reason.

Of all the interesting moons in this solar system

[JessLeah]

...i.e. *kof kof* EUROPA... why Titan?

Hydrocarbon seas. Could there be interest here by the oil industry? Makes you wonder... ;)

Re:color me ignorant, but...

[Patrik_AKA_RedX]

To quote:

Titan bears waves, albeit slow-moving and widely spaced, 7 times higher than waves on Earth

Huge waves! Titan is going the surfers paradise of the future!

Data points!

[2nd Post!]

We barely understand weather on Earth; any and every bit of information we have on storms outside of Earth helps us to understand storms, and weather, on Earth, for one.

So that means waves on Titan and spots on Saturn.
This boils down to fluid dynamics, energy exchange, and chaos.

This also means it applies to helicopters, airplanes, submarines, cars, drip irrigation systems, washing machines, tornado prediction, and the lottery!

Re:Data points!

[no longer myself]

We barely understand weather on Earth

Don't tell that to the local news/meteorologist in my neighborhood:

"For the most accurate, up to date, team coverage that affects your life: Turn to the most dependable weather station in the area!" These guys really understand the weather! I mean, they're right almost 51% of the time!

Oily sludge

[Anonymous Coward]

The model assumes Titan is pockmarked with seas made of 70 per cent ethane, 25 per cent methane, and 5 per cent nitrogen, and partially coated with an oily sludge.

That's no moon, that's a teenager!

Re:Of all the interesting moons in this solar syst

[11223]

While Europa is interesting for potentially having a liquid water ocean underneath its crust, I'd personally rank Titan more interesting for the liquid hydrocarbon soup, which tends to form organic things over time. I just hope that this mission is only the start of our explorations of the moon.

Re:color me ignorant, but...

[essreenim]

Yeah.. lets turn Titan into a planet sized brewery. Its got all the chemicals we need in abundance. With all that Etane, we can produce the ethanol needed for a good beer. Extraterrestrial beer!! I wanna drink!

Life imitates art?

[bpbond]

Code Of The LifeMaker, by James Hogan, is a SF novel about the first explorations of Titan--nitrogen atmosphere, methane seas, water-ice continents covered by nitrogenous-hydrocarbon soils. And, of course, its indigenous population of sentient, medieval robots, that destroy the first Terran probes and subsequently meet humans.

Hogan's a clunky, dated writer, but it's an entertaining read. And if Huygens mysteriously fails on the surface next year...

Saturn simply looks cool

[Altima(BoB)]

I hope I'm not the only one, but looking at those pictures made me remember how beautiful Saturn is... it has a sense of unreality about it, it just looks so perfect. The atmosphere's bands all seem to be perfect rings around its surface, one part of me asks "why," the other part thinks "who cares, it looks pretty."

I know this could prolly be considered off topic, but I was just struck by the pictures of the planet and I wonder how, when so many dazzling images of space exist, can anyone act so ambivalent about space programs? It just doesn't make sense to me.

Oh and was I the only one who pictures a bizzare version of The Perfect Storm when reading about those waves, a more boring movie with less waves and it takes longer to climb each one. I think Hollywood should begin pre-production in May.

Re:Of all the interesting moons in this solar syst

[essreenim]

I really believe thatss what Bush administration wants from space program - American domination of the future resources of the world. Oil reserves may be exhausted by 2050. But if they are correct about the composition of Titan's atmosphere, then thats probably the place to focus on.
Physicists are interested in planets like Jupiter, chemists can leaarn allot from planets like Titan. Mars has plenty to keep geologists, and physical geographers happy. And they all have plenty to amuse meteorologists, SETI buffs, and space historian types....

I see your point though. They all pale in comparison to the incredible diversity found on terra firma - Earth.

If ET ever does want to visit this solar system, you can be pretty sure he'll go straight for Earth!!

Re:color me ignorant, but...

[stef49]

The dots are not important!

The arrows are because they prove that there is an intelligent life on Saturn.

4 big arrows like those can't be caused by a natural phenomenom.

Re:Of all the interesting moons in this solar syst

[Waffle Iron]

The problem with Europa is that the interesting part is buried under dozens of miles of solid ice. Titan is probably the moon that has the most interesting features that are directly accessible with 1997 technology.

Anyway, IIRC there are some future missions on the drawing board intended exclusively for Europa.

Re:color me ignorant, but...

[Anonymous Coward]

Do all the hydrocarbons on Titan make it a good spot for mining/drilling?

Not really. The energy it would take to bring a pound of hydrocarbons back to Earth from Titan is likely much more than you'd get from burning it.
(30 km/sec is equivalent to 450 MJ/kg; burning gives about 10 MJ/kg).

Cassini probe's Blog

[jayrtfm]

The Cassini probe has his own blog.
Anthropomorphized space probe's blogs started in January, and got more popular last month when some JPL'ers started ones for the GOES and FUSE satellites.
Here is a list of 14 active space probe's blogs.

Re:Why are major "storms" in souther hemisphere?

[barakn]

Saturn's southern hemisphere is currently receiving more sunlight (i.e. summer), so one might expect solar heating to cause turbulent convection in the southern hemisphere. Half a Saturn-year from now (15 Earth years), there may very well be storms in the northern hemisphere. El Nino is a bit of a red herring. There's only been one recorded hurricane in the southern Atlantic (this week), and hundreds in the northern Atlantic. The distribution of land masses is asymmetric, so we should expect this.

Jupiter, on the other hand, has an obliquity of only 3.08 degrees, so there should be little or no seasonal effect. The Great Red Spot is truly mysterious.

Re:Of all the interesting moons in this solar syst

[STrinity]

Oil reserves may be exhausted by 2050. But if they are correct about the composition of Titan's atmosphere, then thats probably the place to focus on.

Dude, do you have any idea what you're talking about? If we could import oil from the outer solar system at anything resembling a reasonable price, we wouldn't need oil.

Copying an old experiment

[techno-vampire]

Back in the 80's, JPL changed the course of Voyager I to go behind Titan. The distance at which the signal started to drop, and the rate it dropped at gave us very good measurements of the atmosphere's depth and density. In fact, if the probe's distance from the center of Titan had been cut in half, it would have crashed. That's right, it was less than two radii out! I know, because I worked with the man who wrote the navagation system they used back then (The late Daniel J. Alderson.) and stll know, slightly, the man who used it for this, Bob Ceserone.