1. #1 bobh
    August 1, 2009

    Freeman is a dear friend and I love his optimism about the future. I agree that one should try to detect things based on the fact that it could be detected and not because it is probable that it exists. One nit I would raise with his talk is that, to the extent that reflected sunlight from the life form is detectable in the outer solar system it is a measure of the inefficiency of the evolved mechanism for concentrating and capturing the sunlight. In a very low sunlight environment the organism that will dominate will likely be one that maximizes the capture of sunlight as well as its concentration.

  2. #2 NewEnglandBob
    August 1, 2009

    He is delightful and informative. I enjoyed this talk a lot.

  3. #3 RBH
    August 2, 2009

    bobh raised the same objection that struck me as I watched, though I think it’s more than a nit. Jacklighting (or “shining”) deer (or rabbits in New Zealand) works because there isn’t strong selective pressure to hang on to every photon. So I’m dubious about the detectability Dyson posits. (BTW, one can’t jacklight humans because our choroid layer absorbs incoming light.)

  4. #4 Deen
    August 2, 2009

    I agree with bobh and especially RBH: any organism that uses reflectors to concentrate sunlight will not reflect it back to us. Instead it would reflect it towards some sort of solar energy converter, probably using something similar to chlorophyll.

    I also wonder a bit how likely it is for something to evolve for living above the ice on Europa. It might be that the difference in environments between below the ice and above the ice is too great.

  5. #5 OneSeeker
    August 4, 2009

    This talk, while interesting, makes a lot of major assumptions. Maybe I’m a little naive (or uneducated) about this topic, but I feel like we’ll find life in a completely new form. It will be very unlike anything we have ever discovered before… perhaps the need for sunlight will be missing entirely, perhaps the creature will process of hydrogen rather than O2 or CO2 (since H is obviously more abundant in the vacuum of space — and I use the term “abundant” very lightly). But ideas like this one will more than likely allow us to find something completely UNlike what we actually started out looking for.

  6. #6 Paladin
    August 4, 2009

    I love Dyson’s imagination, and the fact that he’s not afraid to think big. Want a heavy and fuel efficient spaceship to go fast? Just blow some nukes under it. Need a really huge amount of energy? Just enclose a star with some form of energy-capturing fabric or device.