A Brief-ish History of SETI. Part VI: The Great Silence and the Great Filter

The Allen Telescope Array in Northern California is dedicated to astronomical observations and a simultaneous search for extraterrestrial intelligence (SETI). Credit: Seth Shostak/SETI Institute

In the closing decades of the 20th century, several proposed explanations were put forward for why humanity has not yet found evidence of extraterrestrial intelligence in the cosmos.

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