Moon and clouds over the Pacific Ocean, as photographed by Frank Borman and James A. Lovell during the Gemini 7 mission. Image credit: NASA.

Are Human Beings The Only Technologically Advanced Civilization In The Universe?

The truth might not be ‘out there’ at all.

There may never have been another intelligent, technologically advanced alien species in the entire history of the Universe. When you take into account that there may be 400 billion stars in the Milky Way, up to three potentially habitable worlds in many of these star systems, and some two trillion galaxies in the entire Universe, it seems like intelligent life is an inevitability. But our intuition can often lead us astray; what we feel is no substitute for science. The magnitude of the unknowns that abiogenesis, evolution, long-term habitability and other factors bring into the equation throws many of our assumptions about life into doubt. It’s true that there are an astronomical number of possibilities for intelligent, technologically advanced lifeforms, but the huge uncertainties make it a very real possibility that humans are the only spacefaring aliens our Universe has ever known.

The longest untethered spacewalk ever, by NASA astronaut Bruce McCandless, aboard STS-41-B. Image credit: NASA.

Back in 1961, scientist Frank Drake came up with the first equation to predict how many spacefaring civilizations there were in the Universe today. He relied on a…