“It is a High Probability” — Alien Signals We Receive Will Be From a ‘Civilization That No Longer Exists’ (Today’s Most Popular)



If an extraterrestrial civilization civilization lasted less than 100,000 years — the time it takes light to cross the galaxy — then the odds of the signals reaching Earth while the civilization is still broadcasting are vanishingly small. Humans, for example, have been transmitting radio waves for only about 80 years, so our radio waves cover less than 0.001 percent of the Milky Way.


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