Kipping on Grabby Aliens - by Robin Hanson
If you recall, our grabby aliens analysis tries to explain 3 key datums: a) we don’t see any huge alien civs in our sky b) we have arrived at a very early date in the universe, and c) there is only ~1Gyr left for life on Earth. Each datum allows us to estimate a matching parameter of our 3 parameter model: a) alien civ expansion rate, b) time constant for appearance rate, c) power in power law of appearance rate. We can thus roughly estimate the spacetime distribution of such visible alien civs.
[3.] The theory invokes what to me is a kind of Get Out of Jail Free card. It states the grabby aliens are all expanding at speeds close to the speed of light. … [But] there is no experiment we can design that can falsify this hypothesis, even in principle.
far simpler hypothesis is twofold. First, M dwarfs don't permit creatures like us to develop on them, solving the Red Sky Paradox and our apparently early emergence in cosmic history. Second, the emergence of aggressive expanding civilizations just doesn't happen for some reason. …
