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Titan's Tropical Weather
Hugh Pickens writes "Climate researchers Ray Pierrehumbert and Jonathan Mitchell at the University of Chicago say that Titan, the only moon in the solar system large enough to support an atmosphere, has many of the same weather features as Earth, but with completely different substances that work at temperatures that plunge down to minus 170 degrees Celsius. Pierrehumbert and Mitchell call Titan's climate 'tropical,' a climate that is warm to hot and wet year-round, because on Titan methane assumes the role of water and exists in enough abundance to condense into rain and form puddles on the surface. Titan's tropical nature means that scientists can observe the behavior of its clouds using theories they've developed to understand Earth's tropics. For example, Titan's atmosphere produces an updraft where surface winds converge to lift evaporated methane up to cooler temperatures and lower pressures, where much of it condenses and forms clouds, 'a well-known feature on Earth called an ITCZ, the inter-tropical convergence zone,' Mitchell says."
Dominant Meme
It is nice to see a climate model that adds in the information we have gleaned from the equatorial deserts on Titan. Much of the equatorial dark terrain on Titan is covered in sand dunes (made of organics, rather than quartz sand) while the bright material near the equator looks very much like the desert US southwest, with large mesas carved by the action of flowing methane, suggestive of short-duration, but high-volume, rain showers at equatorial latitudes. Much of the climate studies done recently have focused on the weather at the poles, were the majority of large clouds systems, lakes, and seas have been observed.
The Gish Bar Times - Blog covering Jupiter's moon Io
I'd say the biggest factor in determining if it's habitable is going to be its orbit and period, because if it's way off from our 24-hour day or 365~ day year, people would have a harder time adjusting than if it were simply lower gravity or hot or cold.
Titan does not really have "days" because its thick atmosphere spreads the warmth fairly equally to the day and night side. Besides, Titan is too cold for Humans. It is interesting in that it is doing on the methane level what Earth does on the water level. It's like a parallel universe where the water is instead methane. However, we humans are not compatible with that one. The "problem" is roughly comparable to an antimatter universe working like the matter universe (weather, rocks, etc.), but an antimatter being can't just move to the matter version as is.
Table-ized A.I.
I think the GP concern of "days" is the length of when you have light, not temperature. I don't think it's that much of a concern though because there would be so much less light anyway. I think the "nights" where Titan is closer to the Sun might even be brighter than "days" because you get the diffuse reflection of sunlight off of Saturn. The times where the moon is behind Saturn are going to be extremely dark though.
I'd have to disagree -- people live in different areas of the earth where days are of vastly different lengths. And while it's not super healthy, many people live on all manner of strange day cycles with artificial light. I have read that without any clues as to time, people don't naturally settle into a 24 hour day anyways, and that in fact they vary their sleeping cycles longer and shorter over time.
:)
On the other hand, low gravity wreaks havoc with bones and blood vessel walls and such. Hot and cold we can control pretty well, so that's not a huge concern, though it certainly makes it more expensive. Radiation and such may also be a concern for planets without a strong magnetic field. And then there's the whole sustainable artificial ecosystem thing we've yet to work out to any real degree
Overall I think living on another planet is going to be a lot harder than we generally expect. We take for granted how well adapted we are to the specifics of planet Earth, and how much we depend on millions of other things that are also well adapted for the specifics of planet Earth. As someone suggested: it would be much easier to build a colony on the bottom of Earth's ocean than another planet, but we haven't even done that yet because it's cost prohibitive and the benefits aren't clear.
But we'll get there someday, I suppose!
Cheers.
Many cold worlds exhibit cryovolcanism. Some cold moons are also experiencing tidal forces. Some worlds may have underground oceans. Sun is not the only source of energy out there. There is kinetic energy as well, and cryovolcanism, tidalism, oceans, and geoactivity may provide it in abundance.
It looks like self-reproducing molecules on Earth have been successful in utilising every form of energy they could find, even in harsh underground environments. With such a determination to live and reproduce, I think that some molecules on a cold world could utilise kinetic energy to sustain their reproduction.
Although living cells are *mostly* carbon, hydrogen, and oxygen, several other elements are indispensable to life.
And you won't get very far without iron and/or some other transition element that you can use to push electrons around to catalyze reactions. I'm not thinking hemoglobin but rather oxidative phosphorylation/electron transport chains or some xenobiochemical equivalent.
The other problem is that life on earth thrives because we are able to create a "barrier" between the polar world around us by using phospholipids. That way we can divide the world into "the water outside the cell" and "the water inside the cell", and then control the "inside" to our liking.
In a methane world, where your solvent will presumably be some organic substance, instead of water: what do you use as an relatively impermeable barrier? Personally I'd love to see organisms with crystalline cell walls, however I imagine growth and reproduction would be a bitch.
Seven puppies were harmed during the making of this post.
Well its about twice as cold as the coldest place on Earth. But thats better as being twice as hot. Cold is much easier to engineer around.
With all that Methane in the atmosphere I wonder if you could get a modern vehicle using an internal combustion engine to work on the surface of Titan. Just put liquid oxygen in the fuel tank and feed it in through the fuel injection system.
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