Professor Brian Cox argues alien species may have accidentally made themselves extinct.
With at least 100 billion planets in the Milky Way, you d think at least one would have produced a race of intelligent alien beings.
So how come we ve never seen signs of space aliens even after decades of SETI search for extraterrestrial intelligence research?
Scientists have long puzzled over that simple question.
Now, one of England s best-known physicists, Professor Brian Cox of Manchester University, has weighed in with an answer.
In other words, we haven t seen signs of extraterrestrial life because alien civilizations that did exist are now gone ― and, presumably, alien civilizations that might exist now are too primitive technologically to have made their presence known to us.