At least a trillion alien civilizations have ‘almost certainly existed’ in the universe

Billionaire entrepreneur and founder of SpaceX Elon Musk often weighs on robots, Mars colonization, and aliens.

On Sunday, his convictions about the existence of extraterrestrial life got a boost — this time from an article in the New York Times by astrophysicist Adam Frank, which is provactively titled “Yes, There Have Been Aliens.”