Possible theories.

Main Idea

The Fermi Paradox asks why, if the universe is so vast and old, we haven't detected any signs of other civilizations. One possible answer is not that intelligent life is rare, but that our search methods are too narrow. Decades of SETI research have focused mainly on radio signals, because that's the technology humanity happens to use. But a civilization even a few centuries more advanced than ours might communicate through methods we haven't considered practical to search for: modulated neutrino beams, structured gravitational waves, or signals embedded in light itself in ways that look like natural astrophysical noise to instruments tuned for something else. Under this idea, the galaxy could already be humming with communication, just on channels we don't yet know how to listen to.

Reasoning / Evidence

No reasoning provided.