Naked Science Forum
General Science => General Science => Topic started by: GlentoranMark on 18/01/2010 03:42:02
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Carl Sagan said life is abundant in the Universe but why can't we create it in the lab?
I know this is a fundamental and difficult question so how close are we to answering?
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First, although Carl Sagan may have believed life is abundant in the Universe there was no empirical data to support his view. It was simply his informed opinion. In general, his informed opinion was almost solely based on his belief earth like planets MUST be numerous, given the enormity of the Universe.
Unfortunately, we now have empirical evidence to the contrary. Our observations of about 300 planetary systems seem to actually preclude, at least, advanced life form on in any of them. Further, the structures of these planetary systems are remarkably similar in that all but one of them, I believe, have gas giant planets close to their suns. If this is the norm, then advanced life, perhaps any life at all, is very very rare indeed.
In addition, many interested SETI scientists and others have made imprudent statement to the effect we should have intercepted a signal by now. And if not now, certainly in the immediate future. This prediction has been going on for close to half a century now. Again, there is no empirical data to support those hopes. It might happen, but we have no basis to predict that it will happen.
As for creating life in the lab? We know what constituent chemistry is required, but we have never come close to moving from chemistry to molecular reproductive life. In some ways it is an embarrassment. And no one has even a clue, not even a theory, as to how this transition came about. Surely, it is far to early to claim human levels of intelligence are unique to planet earth. But remember, humans are an entire aberration on earth its very own self.
For instance, the dinosaurs had tens of millions of years development. Not one of them came close to describing the plane geometry. Further, none of The Great Apes even come close to us. Finally, even given our gloriously Goldie Locks planet, even our own species was, apparently, reduced to near extinction in one or another of the past ice ages. Geneticists claim they have reason to believe our own species was reduced to no more then a few thousand individuals.
We are by orders of magnitude the strangest species ever to have lived.
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Of course life is rare. 300 is nothing. There are hundreds of billions of stars in a galaxy, and hundreds of billions of galaxies. With numbers so ridiculously large you don't need much chance.
And what do you mean "no one has even a clue, not even a theory"? Look up abiogenesis. Here is my favourite youtube video on the subject
Scientists have actually created a ribonucleotide from scratch with chemicals and conditions that might have existed on early earth: http://www.nature.com/news/2009/090513/full/news.2009.471.html
There was also an interesting article in New Scientist in October titled "Papa was a foaming stone"
http://www.newscientist.com/article/mg20427306.200-was-our-oldest-ancestor-a-protonpowered-rock.html?full=true
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Another way of looking at this question is to consider the chances of something occurring in relation to volumes (of potentially life bearing substrate) and timescales.
If the chance of some form of life spontaneosuly occurring is say 0.000000001% per metre cubed of "primordial soup" per year then the chances of it occurring in a test tube in a lab in a human lifetime are more or less nill. However, with the same chances, in a primoridial soup covering 2/3 of an earth sized planet over a period of 300 million years, the chances ofg life appearing are actually quite high.
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Life exist, we are proof on that, but it might be more rare than we would like it to be. But then we don't really know what 'life' is either. We deem it from where we stand.
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Our observations of about 300 planetary systems seem to actually preclude, at least, advanced life form on in any of them.
Incorrect.
They preclude the possibility of advanced terrestrial-like life forms. (Spock: It's life Jim, but not as we know it.)
Further, the structures of these planetary systems are remarkably similar in that all but one of them, I believe, have gas giant planets close to their suns.
Incorrect.
0f around 430 exoplanets over 160 (~35%) are 1.0 AU or further from their parent star. Over 80 (~20%) are over 2.0 AU and 36 (~8%)are more than 3.0 AU away. Source (http://exoplanet.eu/catalog-all.php).
Moreover you have ignored the fact that techniques have favoured detection of gas giants close to their parent star and so that is what we have tended to find. As new and improved technologies are brought into the effort the observed patterns of planetary size and type will change.
We know what constituent chemistry is required, but we have never come close to moving from chemistry to molecular reproductive life. In some ways it is an embarrassment.
That is an interesting thought. In what way do you see it as a possible embarrassment? Given that the problem is acknowledged to be extremely complex, that the starting conditions are not well known, and that the time involved for life to arise is likely susbtantial (see Mazurka's post) why would our failure thus far be embarrassing?
And no one has even a clue, not even a theory, as to how this transition came about.
That is unwarranted. If anything the problem is that we have too many theories.