Titan May Have an Ocean 109
olsmeister writes "Titan has been a particular focus of attention because of its dense, complex atmosphere, its weather and its lakes and oceans. Now it looks as if Titan is even stranger still. The evidence comes from careful observations of Titan's orbit and rotation. This indicates that Titan has an orbit similar to our Moon's; it always presents the same face toward Saturn and its axis of rotation tilts by about 0.3 degrees. This data allows astronomers to work out Titan's moment of inertia and points to something interesting. The numbers indicate that Titan's moment of inertia can only be explained if it is a solid body that is denser near the surface than it is at its center."
Re:ice float because it's LESS dense! (Score:5, Interesting)
I'm not sure what the ice on the surface would be made of, or what the density of the liquid methane ocean would be since density depends on pressure, but Methane Clathrate ice is about twice as dense as liquid methane is at atmospheric pressure. Pure methane ice is less dense than liquid methane, so would behave like water ice, but I think it's unlikely to be pure.
TITAN (not Mars or Europa) should be our goal... (Score:4, Interesting)
(... and not even the ice geysers of Enceladus should sway our choice).
Why? Because as Professor Peter Ward claims in his very interesting book on astro-biology "Life as we do not know it", only "Titan holds the promise of not just alien life but of MORE THAN ONE KIND OF FUNDAMENTALLY DIFFERENT alien life". (emphasis mine). There could be."three distinct empires of life, from two entirely different trees; CHON life of two kinds (ammono and water CHON life) and silicon life." (p. 234). While he said the "CHON ammono life would be found, presumably beneath the ice, in the ammonia ocean" and the "silicon life would exist, if it existed at all, in the ethane-methane lakes of Titan's surface" he thought the "earthlike" CHON life would be found in the transient freshwater lakes after an asteroid or comet impact.
Well, if there is a (huge) water ocean beneath the ice (and below the ammonia ocean?) the earthlike CHON life wouldn't have to depend on transient impact events! I guess the reason why the researchers believe the ocean to be water (as opposed to the methane the Technology Review editors seem to think), is because the temperature and pressure at those depths make water the most likely candidate. So anyway to recap, on Titan there are a possibility of THREE COMPLETELY different "empires" (his term) of life with only one of them having even the remotest possibility of being anything like life on earth (even if it is earthlike CHON life, that means only that it uses the carbon and other atoms at energy levels corresponding to liquid water, they might not use DNA, RNA or even proteins!).
The reasons why (he suggests) we should skip over Mars, Europa (and I presume Enceladus) is as follows: while Mars was certainly once capable of supporting (Earthlike CHON) life, now it is cold, dry and likely dead. For Europa (and Enceladus) he claims that while they have the liquid water necessary to support (again earthlike CHON) life, they don't have enough energy. His calculations show that the gravitational flexing caused by Jupiter, the main source of energy for Europa, would only be enough to drive a modest ecosystem that would be dispersed in an ocean of millions of cubic kilometers of water. Too dilute to be sustainable. (The same would be presumably be true to an even greater extent of Enceledus).
Titan, on the other hand, is large enough to presumably be able to generate heat internally (it is the largest moon in the solar system) and also gets (some) energy from tidal interactions with Saturn. An interesting additional input is the (weak) ultraviolet rays from the (distant) sun that hits its atmosphere (the only substantial one of any moon) and creates a whole host of organic compounds. Finally if his speculations on the other empires of life are correct, their much colder metabolism may allow (require?) them to exist on much less energy our liquid water based ones do.
This is, of course, rank speculation but the finding a new empire of life would be truly monumental, it would mean life is likely present in every solar system in the galaxy. Of course even finding "earthlike" CHON life would be astounding. Anyway, if the beauty of Saturn's rings weren't enough, this is another great reason to go back. Besides landing and exploring Titan could be comparatively easy. Aeorobraking, aerocapture and reentry will save a lot of fuel compared with landing on an airless world. Parachutes alone will work extremely well in the dense atmosphere and low gravity (unlike Mars) as will planes and hot "air" balloons. The surface ocean is likely to be very calm so boats and submersibles should be usable. There is also land for rovers and drilling operations. The only problem is distance (and money), so let's get cracking on nuclear powered ion engines!
Re:Interesting Stuff (Score:5, Interesting)
Honestly, Titan would be as "done" as the Moon is "done" today. Been there, done that, pretty boring piece of rock in the sky really that nobody's bothered to visit for almost 40 years. If we go there, yeah there's methane in fluid form but it's sterile like an operating room it will be just another one of those rocks.
If you really wanted to be the inner geek, you should go back to Leonardo da Vinci's time, when you could be a multi-discipline genius and most of his inventions really were hands on. Between electron microscopes, giant telescopes, huge particle colliders, robots and probes it's mostly reading stuff out of devices. And when it comes to space on the one side the Mars landers aren't being on Mars, on the other it'll take most of the "news" out of going to Mars. Now here's images just like the landers - except with people in them.
Personally I think one of the most exciting parts of space - searching for other earth-like planets - is happening right now. Good candidates are likely to show up in my lifetime, not in 500+ years. If we can find some, then going to Titan is a lot less interesting. Then people will dream of crossing the interstellar void and reaching "new earth". That's the thing about science, we always move the goal posts.