3 ms·
As stated in the paper: “The second of our three model parameters is the (assumed universal) speed at which grabby civilizations expand. Our model predicts that
by cwillu 3y ago
As stated in the paper: “The second of our three model parameters is the (assumed universal) speed at which
grabby civilizations expand. Our model predicts that on average at grabby origin dates,
a third to a half of the universe is within grabby-controlled volumes. So if the grabby
expansion speed were low, many such volumes should appear quite large and noticeable
in our sky. However, as noted by (Olson ’15; Olsen ’17) and discussed in Section 13, if
their expansion speed were within ∼25% of lightspeed, a selection effect implies that we
are less likely to see than to not see such volumes. Thus if we could have seen them, they
would likely be here now instead of us. As we do not now see such volumes, we conclude
that grabby aliens, if they exist, expand very fast.”
- cryptonector 3y agoThey couldn't be cohesive civilizations though, not unless their individual lifetimes were very long.
- ben_w 3y agoWhile true, a poor choice of name doesn't invalidate the logic. I'd call them "lineages" for this reason, but I don't really expect the name to catch on.
- cryptonector 3y agoIt's just not a single cohesive civilization. Though it would be fascinating. Imagine if our world were seeded with life and terraformed (which now would be quite the misnomer) to be able to host the human-like spawn of a human-like "civilization" that very slowly and discontinuously spread through our corner of the galaxy. That would be quite something, though how would we know unless the parent civilization left us clues to this? And they would have to, if they wanted us to eventually further spread the species/whatever. Or maybe we are sui generis and about to embark on such a program. Or maybe we are about to run headlong into another's such program, possibly causing conflict. Or maybe it's all much too unlikely. I wouldn't know.