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Scientists Offer 'Overwhelming' Evidence Terran Life Began in Space
An anonymous reader writes "Using data from recent comet-probing space missions, British scientists are reporting today that the odds of life starting on Earth rather than inside a comet are one trillion trillion (10 to the power of 24) to one against. That is, we're not originally from around here. Radiation in comets could keep water in liquid form for millions of years, they say, which along with the clay and organic molecules found on-board would provide an ideal incubator. 'Professor Wickramasinghe said: "The findings of the comet missions, which surprised many, strengthen the argument for panspermia. We now have a mechanism for how it could have happened. All the necessary elements - clay, organic molecules and water - are there. The longer time scale and the greater mass of comets make it overwhelmingly more likely that life began in space than on earth."'" jamie points out that the author of this paper has many 'fringe' theories. Your mileage may vary.
Soooooo, they used two numbers (mass of clay & # of comets) to generate a 1e24 to 1 odd against life having started here? Seems like they might have left one or two variables out of their equation. Hopefully this is just junk reporting rather than junk science.
1984 was supposed to be a warning, not an instruction manual.
What is an "old" comet? No comet we're going to encounter is going to be any older than the solar system itself. Most of these comets would, in fact, only be a few hundreds of millions of years older than the Earth itself, and quite likely would have spent a great deal of their time on the outer bounds of the solar system.
We know that life was here between 3.5 and 3.9 billion years ago, with some iffy evidence suggesting it was even older. That gives us a net time advantage for any given comet of no more than about 500 million years. That sounds like a lot, but in reality it really isn't that big a span. Beyond that, considering that our knowledge of cometary history is still rather sketchy, and that our sample size is exceedingly small, this is nothing more than a pretty substantial "what-if", itself based upon one particular abiogenesis theory, which has been somewhat supplanted in recent years.
If we're going to start talking about interstellar comets, to add more time to the equation, someone is going to have to a) provide evidence of such bodies and b) provide evidence that radioactive decay is going to produce heat long enough for liquid water within the body to act as an incubator for the VERRRY long stretches of time that some organisms or proto-organisms are going to survive.
Now, weight all of this against the fact that the early Earth had all the ingredients for life to develop; *plentiful* amounts of liquid water and lots and lots of energy (in the forms of solar radiation, atmospheric conditions like lightning and geothermal energy from oceanic vents and vulcanism). Can someone kindly explain to me how a comet, even with clays or clay-like crystaline minerals and some sort of low-level radioactive decay (it has to be pretty low-level too, because anything too energetic or in too high a quantity is more likely going to be delerious than helpful) is going to provide this more wonderful environment.
As with every generation of panspermia advocates, the underlying argument is essentially "We don't think there was enough time for life to develop on the early earth, so we've got to find a way to add more time." Even if we give them this part of the argument (and I frankly think even that is FAR too generous), they still have to explain how conditions elsewhere (comets, other planets orbiting other stars) are somehow more environmentally-friendly to abiogenesis than Earth was.
This is not to slight the largely unrelated idea that comets could have been the source of organic molecules that could have been some sort of organic "seeds" for early self-replicators to develop and to use as raw materials and energy.
The world's burning. Moped Jesus spotted on I50. Details at 11.
I had Prof. Wickramasinghe was one of my Pure Maths lecturers during my first year at Cardiff. He was dreadfully hard to understand.
t icity
My flatmate, who was a paleobotany postgrad at the time, had some very disparaging things to say about him. He had co-authored a few papers claiming the Archaeopteryx was a hoax, based on his poor understanding of the subject matter.
http://en.wikipedia.org/wiki/Archaeopteryx#Authen