While having lunch with colleagues at Los Alamos Labs one day in 1950, Enrico Fermi, one of the most astute physicists of the 20th century, posed a fascinating question. Fermi pointed out that since the universe contains countless trillions of stars, and if even a tiny fraction of these stars had planets that harbored intelligent civilizations, then there must be thousands or millions of civilizations capable of interstellar communications and perhaps even space travel. “So where are they?”, wondered Fermi. Since there are no signs of such civilizations, they must not exist. This is known as Fermi’s Paradox, and it’s bedeviled astronomers and amateur philosophers ever since.
One solution to Fermi’s Paradox, of course, suggests there are no other civilizations… that we’re it. That’s a profound thought in itself, and rather depressing.
Another solution, hardly more inspiring, suggests nascent civilizations like ours destroy themselves by war or ecological catastrophe before developing advanced communications and interstellar travel.
Another says it’s simply too difficult to carry on an interstellar conversation, so no one tries.
Another suggests the basis for communication isn’t radio, but some other technology we haven’t yet discovered.
My personal favorite: such civilizations are here already, we’re simply not equipped to notice. I think of this sometimes when observing small swarms of insects hovering in a beam of sunshine on a summer’s evening. Like us, these little bugs are deeply absorbed by their frantic activity. But do they have any idea we humans exist? Or can they comprehend the Earth-wide civilization around them? I’m pretty sure they have no idea we’re here.
Still others say Fermi’s paradox misses the point. They say looking for signs of extraterrestrial civilizations is akin, in Earthly terms, to sitting in front of the ocean and holding out a dinner plate, waiting for a lobster to jump onto it. Since no lobster appears, then lobsters must not exist. (See the video below, the “lobster scene” from Timothy Ferris’ program “Life Beyond Earth”).
You can have great fun thinking about Fermi’s Paradox. It’s an interesting idea to ponder, especially with the recent discoveries by the Kepler telescope of nearly Earth-like planets around nearby stars. If Kepler can find even a handful of planets from a small sample of stars, then there must be millions more Earth-like planets in our galaxy.
Strange, though, that the interstellar radio waves are so quiet.