I've had a speculation about the Fermi paradox for years. I call it the uniform cooling hypothesis. Not sure if it's original or not. The idea builds on the pre

I've had a speculation about the Fermi paradox for years. I call it the uniform cooling hypothesis. Not sure if it's original or not. The idea builds on the present cosmological model that considers the universe to all be of the same age. If the emergence of complex life in the universe is a threshold or phase transition effect, it might not happen until the universe reaches a certain age in which all conditions are satisfied. At this point you'd have the "simultaneous" (at geologic time scales) emergence of complex life all over the place. If this were the case, what if for some reason (such as multiple overlapping factors all having to be satisfied) the standard deviation in the time dimension is actually small? In other words what if life emerges or hits certain evolutionary milestones at about the same time +/- a fairly narrow window like one million years. If that were the case then the universe would be full of things more or less about as advanced as we are, but very few that are vastly more advanced. The probability of one of those few very advanced outliers existing in, say, this galaxy might be relatively small. Intergalactic travel is many orders of magnitude harder than interstellar travel (which is already brutally hard) and would take millions of years even near the speed of light, so even something like a Kardashev type II or transitional type III civilization wouldn't be likely to cross between galaxies. Something like that could be out there but insanely distant and completely undetectable. We wouldn't see alien interstellar probes, starships, or techno-signatures from anything large scale enough to be detectable because for the most part these things don't exist yet. Would also imply that once we build a starship, that's about the time we should expect to encounter starships. It would be a cosmic-scale version of the principle (and apparent historical pattern) that steam engines appear when it is "steam engine time." Maybe it's just not starship time yet. If the standard deviation is very narrow, you'd have this weird interstellar trick or treat night event where the probes and starships start arriving at about the same time everywhere in the entire universe. At this point maybe everyone exchanges knowledge and technology and you have an insane explosion in complexity, sort of a cosmic Cambrian explosion, and then you get Kardashev type II and III civilizations and onward. Zoom way, way out and it looks like a sudden phase transition of the entire universe from being dominated by non-living physical processes to being dominated by living processes.