Grabby Aliens  

“Advanced aliens really are out there, and we have enough data to say roughly where they are in space and time, and when we will see or meet them.” 

This is the claim that Robin Hanson makes in his Grabby Aliens theory. 

There are two kinds of alien civilizations. “Quiet” aliens don’t expand or change much, and then they die. We have little data on them, and so must mostly speculate, via methods like the Drake equation.

“Loud” aliens, in contrast, visibly change the volumes they control, and just keep expanding fast until they meet each other. As they should be easy to see, we can fit theories about loud aliens to our data, and say much about them.

Furthermore, we should believe that loud aliens exist, as that’s our most robust explanation for why humans have appeared so early in the history of the universe. While the current date is 13.8 billion years after the Big Bang, the average star will last over five trillion years. And the standard hard-steps model of the origin of advanced life says it is far more likely to appear at the end of the longest planet lifetimes. But if loud aliens will soon fill the universe, and prevent new advanced life from appearing, that early deadline explains human earliness. Robin Hanson. Also as a recording.