|MadSci Network: Evolution|
Some believe that the Earth was "seeded" with life from space - living cells or the molecules needed for life to start travelled here inside comets or asteroids. This is called the panspermia hypothesis; Francis Crick is one of its supporters. A variation of this theory is that life first originated on Mars and pieces of Martian rock, blasted off by asteroid impacts, rained down on Earth, bringing life to our planet. Is this hypothesis credible? I guess a very large amount of amino acids (or other organic molecules) must have been brought here if Earth was "seeded" from outer space - could this really have happened the way Crick and others believe? Space is mostly empty, would enough life-carrying asteroids be able to hit us? Wouldn't anything inside an asteroid or a comet be destroyed when it hit the ground? And what about the harsh conditions in space - anything travelling to us would be exposed to extreme cold, vacuum and radiation for millions of years. Are there other flaws in this theory? How is the panspermia hypothesis viewed by the majority of scientists? Is it criticized, considered interesting, or accepted? Please be as comprehensive as possible in your answer.
Re: Is the panspermia hypothesis credible?
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