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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.
If we find life on Mars, the odds are that we put it there.
Once the accidental or purposeful spread of life is possible, then the probability of life spread to neighboring space far outweighs the random formation of life there. Intelligent life existing somewhere only increases the odds of the spread of life.
.....Having a temperature range that allows liquid water to exist .....
That is a rather narrow range as a matter of fact. A planet with an orbit stable enough for such a narrow temperature spec can only exist if the primary star has no similar sized neighbor closer than about 3.8 light years. That alone excludes more than half of all known stars in our galaxy. Most stars are too close too each other.
In addition, any life hosting planet has to meet a number of other critical specs. One of them is the correct spacing to a properly sized star. Huge stars vary their energy output too much over time to keep the temperature stable for any given planetary orbit. If the star is too small, then the planet has to be too close to that star to get enough heat. In that case, the planet can no longer rotate independently. One side, such as Mercury or our own moon will always fact the body it orbits.
The planet also has to be the correct mass. To little and the water and atmosphere will evaporate into space until life can no longer happen or be sustained if it did happen. Too big a mass will let ammonia and methane accumulate, killing or at least severely stifling life. Mars and Venus are only a little smaller and larger respectively than earth.
There are many other specs a planet-star system has to meet, but the ones I mentioned are the most obvious. The spectrum of the star should be a close match for a process of converting light into complex compounds needed by all life forms. The Sun's spectrum is well matched to the energy exchanges and chemical binding forces as evident in photosynthesis. The atmosphere must allow the relevant wavelengths through and screen out the most harmful rays from the sun and outer space.
A little math of probabilities soon reveals that our earth is indeed a very special place. It is highly unlikely that there is another planet like ours in this galaxy. Could it be, just maybe, that some engineer figured out all the needed parameters? Could it be that this One, knowing that He would want to create life, had to first come up with a carefully designed laboratory where His great experiment we call "life" could be performed?
All theory is gray