Titan is "64%" Earthlike?

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Re: Titan is "64%" Earthlike?

Post by Chris Peterson » Mon Jan 09, 2012 3:11 pm

Ann wrote:NASA, however, pursues its "Follow the water" strategy, and it's hard not to think, from how they present their strategy to the general public, that if an extrasolar planet is firmly inside the "habitable zone" of its star and has a rocky composition and an atmosphere, then it "almost certainly" has life, too.
I guess I don't see this. I think a "follow the water" strategy is perfectly rational, since the only sort of life we understand well is our own kind, so it's really the only kind we're equipped to detect- especially by remote means. But I haven't heard much of a consensus suggesting that any habitable planet will almost certainly have life. Researchers are simply looking in the most logical places.

It wasn't long ago that the big question was whether there were any other planetary systems, and how common those might be. We now know that they are extremely common- most stars probably have them. So now we have a new question- how common is life on other planets? And for now, it is a completely unanswered question, with a range of possible answers ranging from nonexistent to ubiquitous. I don't think many scientists take any firm stance on that question at all... though obviously, different researchers make different assumptions, which guide their specific work.
And there are definitely astronomers who say - or seem to say - that if planets definitely lack liquid water, then life may very well find other liquids to sustain itself on these planets.
That seems indisputable. It doesn't, however, mean that life is either inevitable, or even likely, on planets which support liquid-based chemistry- water or otherwise.
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Re: Titan is "64%" Earthlike?

Post by geckzilla » Tue Jan 10, 2012 2:59 am

It's really hard to imagine life in such an environment, especially intelligent life. I mean, you can't even start a fire there, right? What could be analogue to fire in this kind of environment to an intelligent being? It's just too hard for me to imagine an alien existence.
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Re: Titan is "64%" Earthlike?

Post by Chris Peterson » Tue Jan 10, 2012 6:00 am

geckzilla wrote:It's really hard to imagine life in such an environment, especially intelligent life. I mean, you can't even start a fire there, right? What could be analogue to fire in this kind of environment to an intelligent being? It's just too hard for me to imagine an alien existence.
Well, when I think "life" on other planets, I'm thinking more along the lines of prokaryotes or cyanobacteria- the sort of very simple organisms that defined life on Earth for the vast majority of its existence (and which certainly developed under conditions that we might not consider "habitable" as this word has been used lately).

Statistically, given the length of time on Earth which life existed in a simple, barely evolving state, compared with the length of time complex, multicellular organisms have been present, there must be hundreds or thousands of planets with simple life for every one that has complex life.

I wouldn't hazard a guess how intelligent life might develop elsewhere. That's a very different question than how life might develop. In addition, just what does "intelligent" mean? I think it is possible that there are animals on Earth as intelligent as humans (by some metrics), such as some cetaceans. They have never needed fire, or any analog of it... because they are not technological. But not technological doesn't mean not intelligent.
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Re: Titan is "64%" Earthlike?

Post by Flase » Thu Jan 12, 2012 10:33 am

I read a short story once, I think it was P. K. Dick, where the people of the world developed a mass depression because all the planets and moons of the Solar System had been explored and there was no extra-terrestrial life. It was as if people have some sort of emotional need to find life.

But what if we did and there were funny-looking aliens? People wouldn't like it then. They would call them names and start raising their shootin' irons.

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Re: Titan is "64%" Earthlike?

Post by geckzilla » Thu Jan 12, 2012 1:31 pm

People love funny-looking aliens. They're all over Earth already and they're easily some of the most fascinating creatures around. I have no doubt that aliens from another planet would receive the same treatment of awe and curiosity.
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Re: Titan is "64%" Earthlike?

Post by Flase » Thu Jan 12, 2012 10:31 pm

People raise their shootin' irons against leopards and wolves out of fear. Even other people with darker skin can notice intolerance (or even the odd lynching). The first population of alien animals that we come across will be met with fear, particularly if they are intelligent with a civilisation. Uneducated rednecks will start movements to blow these aliens out of the sky...
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Re: Titan is "64%" Earthlike?

Post by geckzilla » Thu Jan 12, 2012 10:38 pm

Well, I hardly think we would be sending those kind of people into space, if we are ever sending them out there. I figure we would be lucky just to get a picture of an alien and I don't think anyone is going to be shooting them with firearms. There's always the fear mongers. Forgive me for being optimistic for once in my life.
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Re: Titan is "64%" Earthlike?

Post by Flase » Thu Jan 12, 2012 11:08 pm

I wonder what George W Bush would have done if they had found aliens and some of his fellow Texans and military personnel had developed itchy trigger fingers...

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Re: Titan is "64%" Earthlike?

Post by Chris Peterson » Thu Jan 12, 2012 11:10 pm

geckzilla wrote:Well, I hardly think we would be sending those kind of people into space, if we are ever sending them out there. I figure we would be lucky just to get a picture of an alien and I don't think anyone is going to be shooting them with firearms. There's always the fear mongers. Forgive me for being optimistic for once in my life.
The only way we're ever likely to see an intelligent alien is if it comes here. So the response depends on where it first presents itself. I'm reminded of the book Childhood's End, where benevolent aliens arrived, and waited an entire generation to show themselves, since they looked like the Devil, and knew that cultural prejudice would prevent their acceptance.
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Re: Titan is "64%" Earthlike?

Post by Flase » Fri Jan 13, 2012 1:11 am

It would be interesting to see what would happen if, for example, we happened to find an ecosystem of creatures swimming under the ice in Callisto. How would newspapers report it? What would the response be? How would callers to talk-back radio react? How would future generations with sophisticated technology treat them?
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Re: Titan is "64%" Earthlike?

Post by rstevenson » Fri Jan 13, 2012 1:28 am

Flase wrote:It would be interesting to see what would happen if, for example, we happened to find an ecosystem of creatures swimming under the ice in Callisto. How would newspapers report it? What would the response be? How would callers to talk-back radio react? How would future generations with sophisticated technology treat them?
That would depend on how good they tasted. :mrgreen:

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Re: Titan is "64%" Earthlike?

Post by Chris Peterson » Fri Jan 13, 2012 1:33 am

Flase wrote:It would be interesting to see what would happen if, for example, we happened to find an ecosystem of creatures swimming under the ice in Callisto. How would newspapers report it?
They would misquote what the scientists actually said.
How would callers to talk-back radio react?
They'd insist on building a wall around the planet to keep them from ever coming here, and seek to criminalize any immigration. Of course, the term "illegal alien" would suddenly become highly relevant.
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Re: Titan is "64%" Earthlike?

Post by geckzilla » Fri Jan 13, 2012 1:33 am

There's room for much more than fear.

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Re: Titan is "64%" Earthlike?

Post by Ann » Fri Jan 13, 2012 1:34 am

Very interesting discussion.

Personally I think it is out of the question that we will find intelligent aliens in the solar system, and to me that sort of negates the question of how we would treat them if we found them here. But if we ever found the kind of creature whose picture you posted here, Flase, I think too many people would just panic. Then again, I very much doubt that any alien would look like that. I believe that all vertebrates on the Earth are too closely related, and therefore too similar in appearance, for evolution to produce anything so similar to our own "monster fish" on a planet whose life forms have never had anything to do with life on Earth. And even if the bacteria on that planet were indeed related to Earth bacteria, I still don't think that alien vertebrates that evolved out of bacteria related to Earth bacteria would look at all like Earth vertebrates.

So what if we were to find bacteria on Mars? That is not out of the question. I think it would lead to all kinds of feverish reactions. Assuming the bacteria had been detected by unmanned probes, I think that a lot of people would demand that we go to Mars to take a look at the little Martians, whereas others would be really scared and think that those critters were going to give us terrible diseases if they ever got into contact with us.

Such a discovery could well initiate a new space race, where different countries fight to be the first to find a way to control the Mars bacteria, and it might well spawn a flurry of doomsday sects who demand that the Earth must protect itself from alien contagion.

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Re: Titan is "64%" Earthlike?

Post by Chris Peterson » Fri Jan 13, 2012 1:35 am

geckzilla wrote:There's room for much more than fear.

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Re: Titan is "64%" Earthlike?

Post by Ann » Fri Jan 13, 2012 1:47 am

Chris Peterson wrote:
Flase wrote:How would callers to talk-back radio react?
They'd insist on building a wall around the planet to keep them from ever coming here, and seek to criminalize any immigration. Of course, the term "illegal alien" would suddenly become highly relevant.
"Build a wall around the planet." That's absurdly, tragically funny, Chris.

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Re: Titan is "64%" Earthlike?

Post by TNT » Fri Jan 13, 2012 3:23 am

What is that thing, anyway?! Please don't tell me that it's a heart coated in fat. If it is, that carving is just plain cruel. Not to mention gross.
Ann wrote:
Chris Peterson wrote:
Flase wrote:How would callers to talk-back radio react?
They'd insist on building a wall around the planet to keep them from ever coming here, and seek to criminalize any immigration. Of course, the term "illegal alien" would suddenly become highly relevant.
"Build a wall around the planet." That's absurdly, tragically funny, Chris.

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How exactly is that tragically funny? I think it's just crass humor.
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Re: Titan is "64%" Earthlike?

Post by Ann » Fri Jan 13, 2012 4:13 am

How exactly is it tragically funny?

I think it's tragic that humans try to solve their problems by building walls. The Chinese started it by building the Great Wall of China. The the East Germans built the Berlin Wall. Then the Israelis built the wall around Gaza. Now I think the United States are building a wall along its border with Mexico.

But the idea of building a wall around the entire Earth is just completely absurd. How would we go about doing that?

What makes the concept even more absurd is that I suspect some people might actually think building a wall around the planet would be a good idea, if scientists announced that they had found alien bacteria in the Solar system.

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Re: Titan is "64%" Earthlike?

Post by geckzilla » Fri Jan 13, 2012 6:26 am

TNT wrote:What is that thing, anyway?! Please don't tell me that it's a heart coated in fat. If it is, that carving is just plain cruel. Not to mention gross.
The blobfish. It looks pretty funny when removed from its habitat. The point is, angler fish may be pretty gnarly looking fish, but there's a lot more to the deep sea (or alien life) than scary. I just picked that one in particular because I thought it was hilarious and just so unexpectedly bizarre like an alien. Does it look scary?
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Re: Titan is "64%" Earthlike?

Post by Flase » Fri Jan 13, 2012 6:32 am

geckzilla wrote:There's room for much more than fear.
Yes. It's about time we moved on from the cold war fear that typified depictions of aliens in 1950s schlock. Even the 1979 Alien movie seems quite modern in many ways with some inspired scenes but the alien itself turns out to be a bit of a one-dimensional slasher schlock monster. Even the most blood-thirsty carnivores on Earth get sated and spend days between kills doing placid things. They can even seem cute like cats and dogs. But this nightmare monster never stops. It just grows a hundred times faster than any mortal creature known to man and craves more and more human flesh!

One day, that should seem quite dated. I wonder what it ate before human beings came along. Maybe the new movie Prometheus will tell us.

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Re: Titan is "64%" Earthlike?

Post by Colin Robinson » Fri Jan 13, 2012 10:06 am

Ann wrote:...These life forms on Titan would need to "eat" nutrients and to get rid of waste products. Would this amount of biomass change the composition of Titan, for example of the atmosphere of Titan, in a way that would be in any way measurable? Could we say that there is probably life on Titan because its atmosphere has a composition that could not be maintained without the constant enrichment or depletion by life forms? And can we say anything at all about what kind of waste products that methane-based life forms would leave behind?
Hello Ann.

On these questions, please read
Have we discovered evidence for life on Titan? by Chris McKay

Briefly, yes, there are features about Titan's atmospheric composition (reported in June 2010) which are consistent with how organisms there could consume available compounds to obtain energy.

The energy-rich consumables include hydrogen, acetylene, and ethane, and there are indeed indications that all three substances are being depleted somehow. The end product would be methane, but there is no obvious way of determining how much if any of Titan's methane is biological in origin.

Scientists working in this field, such as Chris McKay, are not yet saying there is probably life on Titan, because there are still too many ifs, buts and maybes…

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Re: Titan is "64%" Earthlike?

Post by starman » Tue Mar 20, 2012 11:46 pm

Chris Peterson wrote:
Ann wrote:I think I'm even more pessimistic than you are when it comes to any sort of life being able to function on super-cold Titan.
Why? Titan seems every bit as hospitable to life as Earth. What does the temperature matter, as long as you have energy sources (which Titan has in abundance), and liquid solvents (which Titan also has)?

Titan seems very Earth-like in many biological contexts, what with lots of light, liquid oceans and lakes, dynamic weather and the sorts of tidal zones that were probably important to the development of life in Earth. It is only "super-cold" in the sense that it would likely be inhospitable to water-based life. But water is just one of several likely solvents that could be used by life broadly similar to what we have on Earth.
Not sure about the 'lots of light' angle. Even ignoring the inverse square law for the amount of light, the atmosphere is very thick, plus most of the higher-energy radiation, useful to get reactions going, would probably be absorbed or weakened by the atmosphere (any titanoids reading this, please ignore)

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Re: Titan is "64%" Earthlike?

Post by Chris Peterson » Wed Mar 21, 2012 6:44 am

starman wrote:Not sure about the 'lots of light' angle. Even ignoring the inverse square law for the amount of light, the atmosphere is very thick, plus most of the higher-energy radiation, useful to get reactions going, would probably be absorbed or weakened by the atmosphere (any titanoids reading this, please ignore)
There's still a lot of light- more than found in some places on Earth where photosynthesis is important. I can't see anything that would prevent some sort of photosynthesis analog developing on Titan. The power available at the surface probably exceeds 100 W/m^2.
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Re: Titan is "64%" Earthlike?

Post by Colin Robinson » Sat Jun 09, 2012 8:21 am

starman wrote:Not sure about the 'lots of light' angle. Even ignoring the inverse square law for the amount of light, the atmosphere is very thick, plus most of the higher-energy radiation, useful to get reactions going, would probably be absorbed or weakened by the atmosphere (any titanoids reading this, please ignore)
Yes but when a mixture of nitrogen and methane (the main constituents of Titan's atmosphere) absorbs UV radiation, what happens?

Chemical reactions get going there and then, and they are rather like the reactions in the classic Miller/Urey experiment. A range of complex organic molecules form, which precipitate to the surface. The energy that was in the UV rays is not lost, it is converted into a fund of chemical energy sufficient to support simple organisms.