BOOTSTRAPPING A UNIVERSE

David Christian
Distinguished Professor of History, Macquarie University
Sydney, Australia

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Our Milky Way galaxy. ESA/NASA/JPL-Caltech.

We say that computers “boot up.” The metaphor is that of “bootstrapping”: the surrealistic challenge of trying to lift yourself into the air by pulling really, really hard on your bootstraps. Archimedes could have told you why it doesn’t work. You need something else, outside the system of you and your boots, to act as a point of leverage.

So how can you bootstrap an entire Universe (or an entire origin story for that matter)? What can you use to lever a Universe into existence? Many traditional religious systems offered God as both the lever and the force that drew the Universe into existence. Even Newton saw God as holding together a Universe by providing it with a grid of time and space. Without God’s grid, his Universe could not work.

What’s the point of leverage for Big Bang cosmology? One of the most interesting arguments is that the point of leverage is… nothing! Lawrence Krauss develops this exotic idea in A Universe from Nothing: Why There Is Something Rather Than Nothing (London & NY: Simon & Schuster, 2012). Here’s my attempt to make sense of a weird, wonderful, and very important argument.

The crucial point is that nothing is really nothing. In Newton’s Universe, God’s grid allows us to say with precision where a particle is and what it is doing. That means we could say that a particular region of the Universe has nothing in it. But quantum physics is all about probabilities. At the level of the very small scale you can never say exactly where a particle is or how it is moving. So you can never say there is nothing. All you can do is describe a sort of probability mist. There’s always some probability that something will pop out of the mist, even in what looks like a perfect vacuum. Usually, it pops up in the form of a particle and an antiparticle, which annihilate each other so fast that no physical laws or laws of conservation are broken, and the scientific accounting is fine. But occasionally, something pops into existence and… stays. Stephen Hawking showed that this can happen at the edge (the “event horizon”) of a black hole. NASA defines a black hole as “a place in space where gravity pulls so much that even light cannot get out.” If two particles pop out of the vacuum right on the event horizon, they may be separated by just enough for one to go back into the black hole and the other to enter the Universe outside. It will seem that something has come from nothing.

And if you can get a particle from what seems like nothing, why not a whole Universe? That, strangely, is one of the most plausible contemporary explanations for the Big Bang, and it’s the central argument of Lawrence Krauss’s book.

About the author: David Christian is a professor of history at Macquarie University in Sydney, Australia, and cofounder, with Bill Gates, of the Big History Project. In 1989, Christian began teaching the first course on “Big History,” an interdisciplinary field that examines history starting with the Big Bang, and his work came to the attention of Bill Gates through a video course produced by The Teaching Company.

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