Sciency Words: The Fermi Paradox

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:


Enrico Fermi was an Italian physicist, one of the many great scientists who immigrated to the United States right before the outbreak of World War II. He is most noted for creating the first nuclear reactor and the role he played in the development of the atomic bomb.

But that’s not what we’re going to talk about today. Today we’re talking about something Fermi said half-jokingly over lunch.

Where Is Everybody?

Based on some historical detective work, we can say this probably happened in the summer of 1950. Fermi was visiting the Los Alamos National Laboratory. He and a few colleagues were having a lunchtime conversation about flying saucers. Apparently there had been an amusing cartoon about little green men in a recent edition of the New Yorker.

The conversation got serious (sort of) when Fermi suddenly asked: “but where is everybody?” Everyone at the table laughed, but Fermi’s question and the not-entirely-serious discussion that followed would become the basis of what we now call the Fermi paradox.

As a matter of statistics and probability, it seems like advanced alien civilizations should be out there somewhere. There are over 100 billion stars in our galaxy. Many (if not most) of these stars have planets orbiting them. Some of these planets must surely support life, and in at least a few cases intelligent life—life capable of developing interstellar travel.

Even without faster-than-light technology, one or more of these space-faring civilizations could conceivably spread across the whole galaxy in just a few million years. The galaxy is far, far older than that. There’s been plenty of time for the aliens to do it. So where is everybody? Shouldn’t we have heard from somebody by now?

Or so Fermi argued over his club sandwich (or whatever he was eating) in a half-serious conversation about flying saucers. Of course there are plenty of objections to Fermi’s line of reasoning here, but I’m not going to weigh in on that. Not today. I’m saving my opinion for Monday’s post.

9 thoughts on “Sciency Words: The Fermi Paradox

  1. It’s interesting that most things labeled a “paradox” are only a paradox because we don’t like the most obvious conclusion. In the case of the Fermi Paradox, it’s that we’re the only civilization producing species around. It doesn’t necessarily say we’re alone in the universe, but it does imply that our nearest intelligent neighbor may be very far away, outside of the local group of galaxies, at least tens of millions of light years away.

    This actually may be for the best. It’s not clear to me that we’d be here if they were close enough to colonize Earth. Imagine if another civilization had arrived billions of years ago and taken control of Earth’s early biosphere for their own purposes.

    Liked by 1 person

    1. Good point. We might be extinct or enslaved by now. Or perhaps our species never would have been allowed to evolve in the first place, depending on how long ago the aliens came to visit our planet.

      Liked by 1 person

      1. I don’t know that the colonizing species would necessarily have to explicitly decide not to let another intelligent species to evolve. We only have to look at the fate of all the other sub-species of humans, or the current marginal status of the other great apes on the planet, to get an idea that sapient level intelligence may not be an ecological niche that leaves room for rivals.

        Liked by 1 person

  2. Arguing backwards, if advanced technologically-capable lifeforms existed on any planets in our galaxy, they would probably be here now, and as the discussion above notes, we probably wouldn’t. Therefore, we are probably the only technologically advanced lifeform in our galaxy.

    The challenge is to explain why. I suspect you are going to do this next time. I am interested to find out if your opinion is the same as mine.

    Liked by 1 person

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