The Fermi Paradox is a perplexing one, even as exotic-sounding all-caps paradoxes go. Since the probability that alien life exists out there in some far corner of the universe is overwhelmingly high, it's a little weird that we simply haven't bumped into any of it yet.
It's confounding on a conceptual level, for sure, and the subject of countless stoned dorm room bull sessions. But it's also a legitimate mathematical conundrum. Assuming other advanced civilizations have built space-faring satellites and sent them out to explore the universe, some models suggest that one or more should have crept past and spotted us by now.
So would that mean that we humans—we glorious, perpetually warring, resource-extracting, sitcom-producing humans—are the only intelligent life on in the universe?
Nay, say some astro-braniacs at the University of Edinburgh. There's a mathematical explanation for all of this. In fact, alien probes could have already swung through the Milky Way. They might even still be here.
But they'd have to be self-replicating vessels made from space dust and gas that exploit the gravitational fields of small stars to slingshot themselves across galaxies. Got that? It's what Voyagers 1 and 2 did to pick up speed, but they notably lacked the ability to make copies of themselves out of stardust.