2 ms·

It's somewhat reasonable to assume that we're the only intelligent life in our corner of the galaxy (the practical reach of an artificial radio signal), but the

• AgentME 6y ago
  It's been estimated that self-replicating Von Neumann probes could populate our galaxy in 10 million years. I haven't seen an estimate about them populating multiple galaxies, but I assume many could be hit within some multiple of that, and the growth would be exponential. Even if most intelligent life generally doesn't decide to make self-replicating probes, it only takes one civilization in the history of the (observable) universe to do it to make a huge effect. It's possible that life is just likely enough that none of them have yet chosen to or have been alive long enough to create self-replicating probes, but I don't think it's correct to assume that the likelihood value for life would be on the extreme upper end of the range that's compatible with our observations.