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What would Fermi say now about his 'paradox'?

  1. Oct 26, 2011 #1
    When Fermi was asked if he believed in the existance of E.T.s he replied "where are they?" and I think the idea was that if there were E.T.s they should have colonized the galaxy by now. What I am curious about is ... given the fact that the ability to detect earth-like worlds with signatures of life (e.g. presence of methane and oxygen in environment) is currently available and then in one to two hundred years it will no doubt be even better...What factual conclusions might be drawn about the existance of other E.T. civilizations? For example, given the relative ease of spotting life inhabiting worlds in the galaxy can it be a given that any advanced civilization (even one a hundred thousand light years away) would know that there is life on earth? One benefit of answering 'yes' would make the idea that we should have to 'hide' from a potential alien threat mute since they would no doubt have the ability to catalogue the billions of planets through out the galaxy.
  2. jcsd
  3. Oct 28, 2011 #2
    Rather than looking for chemicals specific to life as we know it, the best way of detecting life would be to look for planets whose atmospheric chemistry is out of equilibrium.

    The universe is exceedingly big and light crawls across it painfully slowly when you put it into the context of travelling from one planet to another in timescales relevant to the evolution and growth of civilisation to the point of technological prowess then on to probable self annihilation. The probability of two civilisations evolving to the point where they could detect each other and communicate or even travel to hook up is therefore exceedingly small. Basically, by the time we get detected and ET has come to say hello we won't be here any more.
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