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Evolution doesn't ensure advancement in the sense of greater capabilities or greater longevity or long-term survival either. Most species on this planet have g

Evolution doesn't ensure advancement in the sense of greater capabilities or greater longevity or long-term survival either. Most species on this planet have gone extinct. What's to say that species capable of altering their world don't have a higher risk of catastrophic failure. The time scales are large and there's no evidence to make a strong assertion that we as a species will be around long enough so that we can colonize galaxies. There is an assumption that advanced civilizations will last for long periods of time. It's not clear to me that's valid. And what time scale is needed for galactic colonization? Why should that be different elsewhere?

BugBrother 12y ago
Yes, but that isn't relevant. Maybe 10-90% of technological species do make themselves extinct by a nuclear war or an environmental catastrophe. It isn't enough. To explain the Fermi paradox needs a big killer, like an innocent looking physics experiment that sterilizes a solar system. My point was that we could already be more than a one planet civilization. So all the eggs aren't in one basket. To be clear: That we already could be an interplanetary culture implies that _if_ there is a big killer that explains the Fermi paradox, it is either big enough to take out a solar system -- or it is behind us. The next stop for spreading to the galaxy would be to get outside the solar system. The good part is that the Oort cloud etc is a good training stop over. And it would also insulate humanity there from what happens closer to the sun. (And directly a civilization is interstellar, then it really are multiple cultures (communication lag etc). Those will at least partly be "evolved"/selected for tendency to spread.) Lots of other people since at least Fermi discussed time scales for spreading in a galaxy, it is an old discussion. If you really can't find good references comment and I'll check the usual suspects for references (centauri-dreams.org).
- Scottn1 12y ago
  "To explain the Fermi paradox needs a big killer, like an innocent looking physics experiment that sterilizes a solar system." As I've mentioned elsewhere: Gamma Ray Bursts
  - BugBrother 12y ago
    Ah yes, gamma ray bursts got less common because of changing star formation rates? Really interesting. I had missed the full argument. [Embarrassing :-)] The one I had seen was that closer to the galaxy centre there would be a higher frequency of supernovas per cubic light year, while too far out there would be too little of the heavier elements from supernovas.

BugBrother 12y ago

Yes, but that isn't relevant. Maybe 10-90% of technological species do make themselves extinct by a nuclear war or an environmental catastrophe. It isn't enough. To explain the Fermi paradox needs a big killer, like an innocent looking physics experiment that sterilizes a solar system. My point was that we could already be more than a one planet civilization. So all the eggs aren't in one basket. To be clear: That we already could be an interplanetary culture implies that _if_ there is a big killer that explains the Fermi paradox, it is either big enough to take out a solar system -- or it is behind us. The next stop for spreading to the galaxy would be to get outside the solar system. The good part is that the Oort cloud etc is a good training stop over. And it would also insulate humanity there from what happens closer to the sun. (And directly a civilization is interstellar, then it really are multiple cultures (communication lag etc). Those will at least partly be "evolved"/selected for tendency to spread.) Lots of other people since at least Fermi discussed time scales for spreading in a galaxy, it is an old discussion. If you really can't find good references comment and I'll check the usual suspects for references (centauri-dreams.org).

Scottn1 12y ago
"To explain the Fermi paradox needs a big killer, like an innocent looking physics experiment that sterilizes a solar system." As I've mentioned elsewhere: Gamma Ray Bursts
- BugBrother 12y ago
  Ah yes, gamma ray bursts got less common because of changing star formation rates? Really interesting. I had missed the full argument. [Embarrassing :-)] The one I had seen was that closer to the galaxy centre there would be a higher frequency of supernovas per cubic light year, while too far out there would be too little of the heavier elements from supernovas.