Who proposed Encounter Hypothesis?

The Encounter Hypothesis was proposed by the American astronomer Carl Sagan. It suggests that the emergence of intelligent life is a rare event, and that civilizations may encounter one another infrequently due to the vast distances between stars and the limited lifespan of technological societies. This hypothesis is part of broader discussions regarding the search for extraterrestrial intelligence (SETI) and the conditions necessary for life to develop in the universe.