Funniest comment justifies a funnier speculation? How would it affect us if the aliens turned out to be here already?
This one is a kind of thought experiment triggered by reading T. Rex and the Crater of Doom by Walter Alvarez. It's a kind of autobiography and history of science. In this case paleontology is the science. The general story might remind you of the history of plate tectonics as a major breakthrough in recent years.
He describes things using a different time scale than usual. Sometimes you get billions of years, and other times you get epochs or chronologies of specific layers, or the time periods when certain species were alive, but he is using million year increments, and it got me to thinking weirdly...
So essentially things were almost wiped out 65 million years ago. The earth started with an almost blank slate and wound up with intelligence. But the dinosaurs had 150 ticks of that million year clock. How is it that they never developed any intelligence? You can sort of extend that back to earlier dominant lifeforms, such as amphibians and even certain categories like octopuses. At the other end, you can say the human fork only required a few ticks of the million-year clock. I'd be inclined to start that clock with the fork from the chimpanzee branch of hominids, because after that we wound up with a number of species within the Homo genus, but if you want to run the clock farther back into monkey time, then it still doesn't explain where the dinosaurs missed the boat. There were a number of monkey-like species of reptiles that could have branched towards intelligence. But why didn't they?
I am going with the premise that intelligence is advantageous in an evolutionary sense. It might be premature to accept that premise, but right now we are still the top dogs and appear to be a successful species in many ways.
All of this made me want to speculate on what traces of homo sapiens and our civilizations would survive 65 million years after us. Then the question is why no dinosaurs created similar traces for us to find now. They had many more ticks of that million-year clock, and any evolutionary advantages of intelligence were still there way back when. Just never happened? Or a different kind of civilization that didn't create such artifacts? Or we humans just haven't figured out what to look for? It would be funny if there are traces of dinosaur astronauts on the moon once we start looking around more closely and more widely... Food for thought?