Since the Universe is big and old, and life on Earth didn’t take relatively long to evolve, then life should be everywhere in the Universe.
And yet, no matter how hard we look, we don’t see any evidence of it out there, not on Mars, not sending us radio messages, and not taking over entire galaxies and using up all their energy.
This, of course, is the Fermi Paradox, and it’s an absolutely fascinating concept to think about.
There are many possible resolutions to the Fermi Paradox, but most of them are unsatisfying.
Sure, we could be living in a cosmic zoo, or we fundamentally misunderstand how difficult it’ll be to travel to another star.