The Fermi Paradox is the contradiction between a high estimate of civilisations beyond Earth and the complete dearth of any supporting evidence, as in ships, probes or contact. Exploring why the paradox exists is fun in the writerly way.
Is it because Earth is rare? That sentient life is only an accidental byproduct of evolution. Or that civilisations reach a certain point in their evolution and simply implode? Or they see the rise of any other sentient species in the galaxy as a threat, becoming paranoid predators and seeking out all other life and exterminating it… Oh, that sounds, familiar. *grin*
It’s the size of the universe that makes any communication with other life almost impossible. That’s where Drake’s equation comes in:
N = the number of civilisations possible. The rest of the formula relates to stars, with planets, that can support and goes on to develop life…life that’s intelligent and able to create technology that can reach into space. L= the length of time these civilisations would emit these signals.
It’s not a perfect equation, but it does make it evident that it’s such a remote chance that we’ll ever bump civilisations with someone else.
It definitely has one thing missing. Drake should factor in how many of these civilisations would have fit, gorgeous aliens eager for Earth women… Or perhaps that’s just me. And my plot bunnies.