January 17th, 2007, 03:34 PM
A week or so ago I posted a topic about methane(fluid) on titan. I asked a few questions but there was 1 that the astronomers couldn't answer:
Is life possible on the planet titan with its fluid methane(-180C`, circulating weather of methane)?
what is neccesary for life besides methane(fluid) and weather, by a temperature of -180C`? <-not co2 based but ch4 based.
January 17th, 2007, 06:00 PM
Firstly, astronomers aren't biologists. Astronomers are smart individuals but not knowledgeable of life and biology needs other than as a side interest.Originally Posted by miomaz
There are lots of other variables determining life such as atmospheric pressure, radiation bombardment and so on.
As a geologist and paleontologist I ask the question a bit differently. Not if life could exist in such conditions but could life arise in in the first place and then evolve to continually survive and still survive on Titan. My answer is not based on science but an educated guess and that's 'I doubt it'. Nobody would know with any certainty an answer to your question.
we know that here on earth the cooler the environment the less a metabolism is active, so my guess would be unless there's some real heat, electricity (lightning etc) and geo activivity life would probably never evolve there, remember it took about 500M - 1BN years for life to appear here, in a nice warm oceanic soup being constantly stirred by geo activity and prodded with lightning. If we find nothing at all on mars, not even dinosaur fossils then I'd rate Titan's chances as zero.
Current thinking leans to the notion that life on Earth arose either in the deeps, around 'black smoker' volcanic vents, or deep within the early crust. In either case the organisms which arose would have been chemoautotrophs, deriving their eneregy from minerals within their rocky home, while benefitting from the elevated temperature of their environment.
A young Titan would not have been gravitationally locked with Saturn, but would have experienced large tidal stresses. The heat generated by these, coupled with the heat of formation of the satellite, would have provided a suitable temperature regime within the crust or mantle for life to evolve - if you believe current thinking as to how life evolved on Earth.
Since the composition of Titan is quite different from the Earth it would not be surprising if the metabolisms which developed in any evolving life was different from those which occur on the Earth.
I take your reference to 'not even dinosaur fossils' to be irony, since dinosaurs are pretty much as adavanced as humans or any other mammal.
The absence of a confirmed find of life on Mars, fossil or extant, is much more a reflection of our search technique than of the presence or absence of life on the planet, now or in the past.
No attempt has been made on any mission to search for fossils. The only experiments designed to search for life were carried on the two Viking spacecraft. These provided clear evidence for life, which consensus opinion then rejected.
In the light of these points you can reach no conclusion whatsoever about the possibility of life on Titan based upon our understanding (or lack of it) about life on Mars.
My reference to DIno fossils was purely for the reason that their size is an asset in terms of ability to survive the environment. I'm not sure I subscribe to the geothermal origins of life, of course I accept that life can survive there, and some very primitive kinds [as I understand it] as well, whethre or not that life could move further out into the sterile environment is another matter. My personal opinion is that the environment at or near the surface [rather than deep sea] has a wider variety of conditions for the onset of life to choose from. Remember, wherever you look in the solar system and cannot see the surface of a moon or planet there's some guy who predicts the possibility of life there,
In my own lifetime [and I suspect yours] it has been widely held that life existed on both Mars and Venus - that is animals, plants and intelligent beings. My final opinion was that if there is no, and never has been any life on mars (which seems to have had in the past many earthlike properties) then I personally think there's little or no chance of it forming on a remote moon. - "Current thinking" - is just that, speculation. So why the snide remark in your final sentence?
My final sentence does not contain a snide remark. This is my final sentence:
In the light of these points you can reach no conclusion whatsoever about the possibility of life on Titan based upon our understanding (or lack of it) about life on Mars.
If my argument is not clear, here it is again in expanded form.
1) Your argument appears to be that Mars is a more likely locale for life than Titan. (I would tend to agree with this point.)
2) Your argument continues, that since there is no sign of life on Mars, it is highly unlikely that there is any life on Titan.
3) I assert, with a ton evidence to support that assertion, that we have
a) made very few serious attempts to look for life on Mars.
b) when we have done so we have found evidence for life on Mars.
4)Therefore, it is clear that our knowledge of possible Martian life is considerably less than our ignorance of said life.
5) Consequently to make a deduction about the possibilityof life on Titan based upon the observation of our poor understanding of life on Mars, is pointless.
I trust that is clearer. [The Surgeon Generall has determined that this is a snide free zone.]
Regarding the Viking lander's tests for life on Mars:
Here's an interesting read which details some of the pro's and con's of the interpretations of the various experiments.
The article is actually a flight of fancy conjecturing a possible hydrogen peroxide based life form on Mars which has been passing around the various science news sites of late. Rather interesting idea, even if purely speculative (and perhaps outrageously so.)
Anyway, I think that Ophiolite, for one, will find the portions describing the Viking tests to be of interest. Perhaps others will as well.
*tips hat*
http://lanl.arxiv.org/ftp/physics/pa...10/0610093.pdf
Edit:
Oh. And I fail to see the 'snide remark' as well.
Nothing to see here.
Move along.
(Except for my very interesting article posted above, that is. READ IT!)
Excellent reference. Thank you Invert.
The failureof the GC_MS to detect organic molecules, which the paper mentions, is of course more readily explained by the fact that the damn thing just wasn't sensitive enough.
A must read for anyone interested in this topic area.
Topic Change:
On re-reading my last sentence I think I can see where the snide perception by Megabrain came from.
If you are paranoid, inattentive, and tend to jump to a concussion, rather than a conclusion, then my sentence could have been read thus:
In the light of these points you can reach no conclusion whatsoever about the possibility of life on Titan based upon your understanding (or lack of it) about life on Mars.
Rather than the actual version,
In the light of these points you can reach no conclusion whatsoever about the possibility of life on Titan based upon our understanding (or lack of it) about life on Mars.
Now, you see MegaBrain, the sentence underlined above is an example of a snide response. I hope you see the distinction. (Those last two were also.)
I 'pubicly' apologise to Ophiolite for suggesting his last sentence contained a snide remark, re-reading it I see he wrote 'our understanding' whereas the first time I read it as 'your understanding'.
Very gentlemanly reaction. Thank you.
"No attempt has been made on any mission to search for fossils. The only experiments designed to search for life were carried on the two Viking spacecraft. These provided clear evidence for life, which consensus opinion then rejected. "
???
I'm obviously a lot older than you. Yes, some of us were alive back then. There certainly was NO clear evidence for life. there was a hint of some necessary requirements which is a LOT DIFFERENT from clear evidence of life My collegues snickered at the idea back then almost as much as they snickered at the so-called Martian life-bearing meteorite. It's easy to cherry pick a quote or two but it shouldn't be confused with any 'clear evidence'.
the same bad science appears in the press from time to time. Water is found and some silly statement is made that 'where there is water, there is life'. No it isn;t. Take a pot of sterile water and boil it on the stove and 'surprise' no life. Life isn't magic but a coming together of a specific chemistry. Water or some other variable is no more clear evidence of life than a chunk of bauxite (aluminum ore) is evidence of a Boeing 747.
Your response to some of my observations seemed a little dismissive. I thought that merited a reply. I hope you don’t find it too tedious.
The only evidence I can see for this deduction is that your somewhat rigid thought patterns mirror those often associated with those in their declining years.
Then no doubt, like me you recall the excitement of the Viking landers; the earlier disappointment of the barren, crater riddled surface revealed by the Mariner craft; the surge of emotions created by Kennedy’s inspirational speech at Rice University – (We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard….); the amazement at Yuri Alexeyevich Gagarin’s ground braking (should that be skybreaking?) single orbit; the panic generated by the Soviet Union’s sputnik launch; Chuck Yeager’s record breaking flights in the X-1. Yes, indeed, some of us were alive back then.
Of the three experiments on each of the two landers the Labelled Release Experiment produced results at both locations that, prior to the landing, would have been considered clear evidence of life. The other two experiments provided suggestive results. The principal reason the biological explanation was rejected was the absence of detectable levels of organic material. The gas chromatograph-mass spectrometer designed to detect such material was also unable to detect it in soil samples that did contain micro-organisms.
So, yes, there was clear evidence for life. Clear evidence is quite different from proof. This evidence was rejected on what seem to me exceedingly flimsy grounds, that speak more of politics than science.
I should be fascinated to know what hints there were as to necessary requirements for life being present. I would suggest that the one thing the Viking craft did not return was evidence for the requirements for life. Rather the contrary: an almost total absence of water; no organic material (though the insensitivity of the GC-MS would readily account for that); destructive quantities of hydrogen peroxide, if we are to believe Horowitz and the other apologists.
I have always been suspicious of the Alan Hills sample. However, is snickering not associated more with foolish schoolgirls, than with objective scientists?
I imagine it is. However, I don’t work that way.
I am sure it does. It don’t get my science from the press.
I agree with you completely on this point, so I am at a loss as to why you are lecturing (some might say hectoring) me on it.
can someone please answer my second question?
what is neccesary for life besides methane(fluid) and weather, by a temperature of -180C`? <-not co2 based but ch4 based.
One suspects one would need a powerful suite of catalysts to produce metabolisms that moved at more than 1/1000th the pace of a slug.
but wouldnt this just count for waterbased lifeforms, the temperature for (fluid) methane based creatures would be round 10-40` compared to waterbased lifeforms, this wouldn't need as much heat.
interresting link, i beleve it not to be corrupt:
http://www.space.com/scienceastronom...te_050127.html
Does anybody know when the next flight to titan is?
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