The Loom

In case you were worrying that life on Earth would be wiped out by a catastrophic burst of gamma rays, rest easy. It turns out that our galaxy may not be a very good source of gamma ray bursts. I found this particularly interesting given recent speculation that gamma rays bursts might have triggered mass extinctions in the past. (News article here, original paper here.) The bursts are clearly catastrophic, but probably not close enough to Earth to cause much trouble.


  1. #1 Steve Thorsett
    May 10, 2006

    Actually, the “original” paper was quite a few years earlier than the one that you cite:

  2. #2 John Faughnan
    May 10, 2006

    This makes the ‘great silence’, aka the Fermi Paradox, ever more intriguing.

    One explanation for the fact that the galaxy isn’t swarming with LGMs is that our galaxy is very inhospitable to life. Periodic bursters are a nice way to sterilize chunks of the galaxy, and thus they help explain the paradox. Another historic explanation was that earth-like planets are rare.

    We now think earth-like planets may be not terribly rare. Today we learn that bursters may not be all that common. These modify terms in the old Drake equation, meaning there’s more pressure on something else to explain our solitude.

    Personally, I favor the explanation that the period of time that any technologic culture is interested in exploration and expansion is very short. (That is, biological imperatives never persist).

    The usual explanation is that all technological civilizations turn into gray goo … :-).

  3. #3 Ken Shackleton
    May 11, 2006

    With respect to John’s comments….even if our galaxy had millions of life-bearing planets…the likelihood of technology is still very small. Life would have to evolve into multi-cellular forms….then an intelligence would have to evolve in a creature that is also capable of manipulating its environment. In our case, agriculture was a pre-requisite to advanced technology….yet agriculture also encourages religious development that is often very anti-intellectual. Once the religious [anti-intellectual] hurdle is overcome….then as you say… long does the technology last? Ours is dependant on cheap and abundant sources of energy….and how long will that last for us?

  4. #4 Stephen Uitti
    May 11, 2006

    My favorite explanation to the Fermi Paradox is that interstellar travel is hard. Civilizations might only do it if 1) they can, and 2) when they have to. It isn’t clear that we can, and it will be some time before we have to. It might be easier to siphon off some mass from the Sun to extend it’s life span. In any case, there may not have been enough time for anyone to have to do interstellar migration. The space Arc is going to have to be huge, unless all we send is information. A robot ship could terraform some planet, build all the life forms from scratch…

  5. #5 David B. Benson
    May 11, 2006

    … and then there is the argument in “Rare Earth”, which I commend to everyone.

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