Cassini Finds Evidence For Ocean Inside Titan

Riding with Robots writes "NASA reports that by using data from the Cassini probe's radar, scientists established the locations of 50 unique landmarks on the surface of Saturn's planet-size moon Titan. They then searched for these same lakes, canyons and mountains in the data after subsequent Titan flybys. They found that the features had shifted from their expected positions by up to 30 kilometers. NASA says a systematic displacement of surface features would be difficult to explain unless the moon's icy crust was decoupled from its core by an internal ocean, making it easier for the crust to move. If confirmed, this discovery would add to the growing list of moons in the solar system that are icy on the outside and warm and liquid inside, providing potential habitats. We've previously discussed Titan's hydrocarbon lakes and potential cryovolcano."

Exciting.

Titan is one of the most exciting bodies in our solar system. Having recently read Carl Sagan's Pale Blue Dot, he wrote a fair bit about the abundance of organic molecules on Titan. We seem to keep discovery more and more exciting things about this moon. I

Re:Exciting.

"it sure would be interesting to send a probe in to it and see what we can discover."

We have sent The Huygens Probe [wikipedia.org] Before, but it was not designed to look for an underwater ocean. Lets hope they return with somthing else.

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"but it was not designed to look for an underwater ocean"

Well if you know how to design such a thing I think you could patent it an NOBODY on slashdot would complain about this patent.

Re:Exciting.

Titan is one of the most exciting bodies in our solar system.

Of course, what you say is technically correct. But we really need a different way of expressing it, because when I read: "most exciting bodies in our solar system," I immediately thought: "Jessica Biel".

I suspect I was not alone.

Re:Exciting.

It is still correct to say that it would be interesting to send a probe into it, though.

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that are icy on the outside and warm and liquid inside, providing potential habitats.

Have a look at "Slow Life", Hugo 2003 winner

You might like to have a look at "Slow Life", by Michael Swanwick.
http://www.analogsf.com/Hugos/slowlife.shtml [analogsf.com]

It's a nice sci-fi novelette (that won the Hugo in 2003) about life in the deep seas of Titan.
http://www.nicholaswhyte.info/sf/Hugo2003.htm [nicholaswhyte.info]
http:// [locusmag.com]

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No, there's methane on Mars that isn't necessarily organic in origin [sciencedaily.com].

life on/around gas giants

Life ON gas giants seems like a big NO with what we currently know about the conditions required for life to emerge. But life around gas giants, on their moons seems plausible.

What I'd like to know (read: what I'd like some slashdotter with the required know-how explain to me) is why are these moons hot on the inside, possibly hot enough for water ice to turn into liquid water. It's so incredibly far away from the sun. Is this caused by their size and subsequent internal dynamics?

Also, aren't these moons constantly bombarded with radiation from their host planet's powerful magnetic field? Must be rough for aliens.

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I believe that a gas giant's intense gravitational field can heat the cores of nearby moons.

Re:life on/around gas giants

What I'd like to know (read: what I'd like some slashdotter with the required know-how explain to me) is why are these moons hot on the inside, possibly hot enough for water ice to turn into liquid water. It's so incredibly far away from the sun.

The gravitational attraction between the moon and its parent planet is sufficiently strong that the modest changes in distance (and thus gravity) as the moon orbits are sufficient to repeatedly distort it by a 'significant' amount, which generates heat. It's kinda like a squash ball, which gets warm as it is repeatedly compressed during play.

Re:life on/around gas giants

This is the same process that keeps one side of the Moon facing the Earth, and one side of Mercury facing the Sun. Both of them had some amount of spin long ago, but the squishing removes energy, and the only place that energy can come from is the rotational energy of the spin.

The strength of the effect depends on the relative sizes of the two bodies, and the radius of the orbit, which is why most of the bodies in the solar system aren't tide-locked.

rj

Re:life on/around gas giants

Mercury isn't 1:1 locked (one face always toward the sun). Rather, it's 3:2 locked (three rotations for every two revolutions around the sun). Thus, all of the surface gets periods of sunlight and darkness.

The 3:2 resonance combined with Mercury's eccentric orbit does produce some interesting effects. As seen from certain points on the surface, you could start out in night, watch the sun rise, move a little way up the sky, turn around, set near where it rose, and then later rise again with a noticeably larger apparent diameter and travel all the way across the sky, then set, rise near where it set but now looking smaller again, turn around, and set again.

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Tidal forces are kneading these planets like bread. There's a pretty good about of mechanical forces getting turned into heat.

Fluid interior does not mean warm.

While it is very likely that the interiors of a couple moons in the solar system have subsurface liquid oceans, that does not indicate high enough temperature at depth to consider the interior warm or hot or capable of supporting life. Over geologic time these subsurface liquids (which are thought to be predominantly H2O) have more likely formed through interaction with surrounding rock/metal. As H2O reacts with its surroundings and incorporates various impurities (salts, ammonia, organic molecules) into its structure the melting point is decreased to the point that a liquid or fluid condition is possible at significantly lower temperatures. Although in the case of Ganymede (Jupiter's fourth moon), which posses an internally generated magnetic field, a dynamo action similar to Earth's core may exist providing heat. Whether this is the case on Titan is yet to be determined. The massive amounts of organic components there make it harder to determine if there is an internal heat source or if the mixture of organic compounds are naturally stable at those conditions creating the lakes and cryovolcanoes previously mentioned.

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Supporting life seems fairly easy. As you say, there are extremophiles right here that might be able to make a go in rather unpleasant (to most life) environments.

The bigger question IMO is if life could readily start in such environments. I suppose it's

He just missed the news!

Too bad Arthur C. Clarke passed away on Tuesday (Wed. in Sri Lanka), he would have been very pleased to have his suspicions confirmed like this. Then again, maybe he's hanging with Dave Bowman and HAL. In that case his response might be whatever a stylish English gentleman says instead of "Duh!".

Rest in peace, Sir Arthur, and thanks for giving us "all these worlds."

-- a sad fan who's enjoyed your books for over 20 years

Let's Just Stay in onight...and forever.

So now there's Europa and now Titan that have probable underground oceans, and oceans seem like good candidates for life.

It would be interesting, if in the future, we find that most life actually forms on moons with oceans protected from the vaccum of space.

Maybe out planet, with it's skin lain bare to the cosmos, is an exception for a life-harboring world. Maybe this is why we haven't heard from any other intelligent lifeforms; perhaps they all have severe agoraphobia and just freak-out when they send their first probes up through the surface.

Let's hope the wouldn't suffer from the Krikkit [wikipedia.org] xenophobic mindset, or we might be finding out exactly how good we humans are at international...er, interplanetary negotiations...oh my, I certainly hope we don't have to find out!

Stephen Baxter's book "Titan"

http://en.wikipedia.org/wiki/Titan_(Stephen_Baxter) [wikipedia.org]

Re:icy on the outside and *icy* and liquid inside

Not to be rude, but actually this is incorrect. At low pressures there is some odd behavoir, but on a planetary scale the melting point of water increases with increasing pressure. Ice has several different crystal structures called polymorphs that change as pressure increases. Each requires greater and greater temperature to melt. This is a good page on the water molecule and its behavoir: http://www.lsbu.ac.uk/water/index2.html [lsbu.ac.uk].

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I think the biggest difficulty would be power. Our Mars rovers have been solar powered, but it's unlikely that that would work on Titan, since it's much farther from the Sun, and its atmosphere will block most of what little light does reach it, since it'

Solar power

The Mars rover is solar powered. Titan is too far from the Sun to make that practical. So while a rover could be sent, it would have to be significantly different from the current designs.

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Hmmm, it will sure make a big splash...

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reminds me more of my ex....

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Science fiction: 2001, Star Trek, Lost in Space, ...

Science: space probes, lunar landings, ...

Engineering: solar power satellites, industrial microgravity, ...

Industry: weather satellites, communication satellites, GPS, ...

Science leads to spinoffs in mult