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View Full Version : Alien Life on Titan? Hang on Just a Minute…



Fraser
2010-Jun-07, 07:10 PM
Two papers released last week detailing oddities found on Titan have blown the top off the 'jumping to conclusions' meter, and following media reports of NASA finding alien life on Saturn's hazy moon, scientists are now trying to put a little reality back into the news. "Everyone: Calm down!" said Cassini imaging team leader [...]

More... (http://www.universetoday.com/2010/06/07/alien-life-on-titan-hang-on-just-a-minute%e2%80%a6/)

Jerry
2010-Jun-08, 05:14 AM
"It is the result of a computer simulation designed to fit measurements of the hydrogen concentration in the lower and upper atmosphere in a self-consistent way,"

If your computer simulation has hydrogen disappearing into the surface, you have a very badly behaved computer model. This is just awful.

EDG
2010-Jun-08, 05:18 AM
If your computer simulation has hydrogen disappearing into the surface, you have a very badly behaved computer model. This is just awful.

I would suspect that the scientists in question do actually have some kind of clue about what they're doing and why they're suggesting that the hydrogen might be disappearing. e.g. if some of the hydrogen travelling downwards isn't coming back up again, then it stands to reason that one possibility is that it's being absorbed at the surface by something.

HenrikOlsen
2010-Jun-08, 05:33 AM
"It is the result of a computer simulation designed to fit measurements of the hydrogen concentration in the lower and upper atmosphere in a self-consistent way,"

If your computer simulation has hydrogen disappearing into the surface, you have a very badly behaved computer model. This is just awful.
And if that was what was going on, you'd be right.
What really happened is that the models assumed no absorption and tried to predict the expected distribution of hydrogen and acetylene at different heights in Titan's atmosphere and got a result that don't fit observations.
Surface absorption is one of the possible explanations for the difference between the computer model's prediction and the real observations; life is one of the possible processes for that absorption.

Jerry
2010-Jun-10, 03:20 AM
A few years ago we visited the surface of Titan with a probe: Huygens. The Huygens science team reported that the atmospheric pressure and temperature profiles were smack-on prior estimate. These prior estimates in turn, were based upon the assumption that the moon is very highly differentiate with a dense iron core. A few months ago, Cassini scientist reported that the gravity field of Titan, as determined from multiple fly-bys, leads to the conclusion: Titan is highly undifferentiate; an amalgum of ice and rock. Each of these very different models of the moons core structure will produce a very different gradient of gases in the atmospheric profile; and with no hard reason for assuming either model of the moon is correct it is painfully difficult to draw limits on how the atmosphere could or should be modeled: A differentiated core produces a much more mild atmospheric gravitational gradient than a highly differentiated core; especially at such low temperatures where gases are less than ideal. To model the atmosphere, you can start any where and end anywhere.

But this is not the only difficulty found in trying to model Titan's atmosphere. No one has a good model of what the surface is made of: We have spectra and other data but no known analogs. All we know is that most of the surface is inconsistant with either ice or ammonia - two prime candidates before our visit. For all we know, Titan is a ball of activated charcoal. Then there are the dunes, cloud movements and specular reflections. The sum total of which tells us Titan is as big of a mystery today as it was five years ago, if not more mysterious.

Five years ago we did not have one clue that indicated life is likely to exist on Titan, and we don't have any data today that directly infers otherwise. Good science means starting with the basics: Figure out what the surface is made out of and whether or not it is active. Figure out how in the hell Huygens descent could have followed prior models so closely when the models were built about a highly differentiated core. The data is discordant - there are not strong enough constraints to realize whether or not hydrogen is disappearing from the picture.

Most of all, we need to go back with better instumentation and a good camera and record everything we missed the first time. If jumping around and jacking out speculation that there is life will make that happen sooner, I am all for it, but don't call this blind speculation science, because it is as vacuous as astrology, only more missleading.

EDG
2010-Jun-10, 08:50 PM
Most of all, we need to go back with better instumentation and a good camera and record everything we missed the first time. If jumping around and jacking out speculation that there is life will make that happen sooner, I am all for it, but don't call this blind speculation science, because it is as vacuous as astrology, only more missleading.

Nobody (except some in the media) is actually calling it life. The point of the article is to actually dampen down the idea that life has been discovered. It could be a raft of other things, ranging from inaccurate models to inorganic processes.

Me, I call it all science. Sometimes you're going to get ideas that are more supported or justified by evidence, but it's early days in this field, and I'm sure as we get more data the models will be refined more. Dismissing this out of hand because you think it's "blind speculation" means that you're more likely to miss important things because of your internal biases.

BigDon
2010-Jun-13, 06:01 AM
The gut punch, to me, as far as Titanian life was the discovery of the "recent" massive impact crater that represents a near structural limit hit. You just can't model around that. (what's the name of that crater again?)

EDG
2010-Jun-13, 07:57 AM
What do you mean by "near structural limit hit"? I'm not aware of any massive basins that could have physically disrupted all of Titan, if that's what you're talking about (like Herschel on Mimas).