Where is everybody?

For decades, that question was merely a part of physics legend, the kind of thing grad students over here when their advisors take them out to dinner.

But the story behind that question turned out to be true, and it's a good

story. It was after World War II, and flying saucers had burst onto the scene as this huge

cultural phenomena. And physicists are somewhat like normal people, and when they meet for lunch,

they chat, and sometimes they chat about work, sometimes they chat about their family,

and sometimes they chat about whatever is in the news. And Enrico Fermi, the eminent

physicist of his era, was visiting Los Alamos National Laboratory.

And he was out to lunch.

And over the course of the conversation, it moved to two UFOs and flying saucers.

And the group ended up nerding out over the possibility of space travel. They

realized that for flying saucers to actually be aliens, this had to indicate that it was possible

to travel faster than the speed of light, because that was the only feasible way to travel

amongst the stars in any reasonable amount of time.

And so, you know, if these are aliens, that tells us interesting things about physics.

They're just chatting.

But as the conversation went on, Enrique Fermi went silent, and he stopped contributing.

And as conversations tend to do, they moved on from the UFO discussion and on to

other things, but Fermi remained silent. And then sometime later, out of nowhere, he just blurted it out.

Where is everybody? Everybody immediately knew what he meant. This became the genesis of what is now known as the

Fermi paradox. And here's the basic idea. Life is possible in the universe. You need proof?

Hello, it's nice to meet you. It happened here on Earth. And the universe tends to not just do

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