A Universe from Nothing: Einstein, the Belgian Priest and the Puzzle of the Big Bang

Features | Space

An excerpt from physicist Lawrence M. Krauss's new book explains why we are not the center of the universe

By Lawrence M. Krauss ?| February 10, 2012?|

Image: COURTESY OF SIMON & SCHUSTER

[Editors' note: The following is an excerpt from theoretical physicist Lawrence M. Krauss's new book, A Universe from Nothing: Why There Is Something Rather Than Nothing (Free Press, 2012).]

It was a dark and stormy night.

Early in 1916, Albert Einstein had just completed his greatest life?s work, a decade-long, intense intellectual struggle to derive a new theory of gravity, which he called the general theory of relativity. This was not just a new theory of gravity, however; it was a new theory of space and time as well. And it was the first scientific theory that could explain not merely how objects move through the universe, but also how the universe itself might evolve.

There was just one hitch, however. When Einstein began to apply his theory to describing the universe as a whole, it became clear that the theory didn?t describe the universe in which we apparently lived.

Now, almost one hundred years later, it is difficult to fully appreciate how much our picture of the universe has changed in the span of a single human lifetime. As far as the scientific community in 1917 was concerned, the universe was static and eternal, and consisted of a single galaxy, our Milky Way, surrounded by a vast, infinite, dark, and empty space. This is, after all, what you would guess by looking up at the night sky with your eyes, or with a small telescope, and at the time there was little reason to suspect otherwise.

In Einstein?s theory, as in Newton?s theory of gravity before it, gravity is a purely attractive force between all objects. This means that it is impossible to have a set of masses located in space at rest forever. Their mutual gravitational attraction will ultimately cause them to collapse inward, in manifest disagreement with an apparently static universe.

The fact that Einstein?s general relativity didn?t appear consistent with the then picture of the universe was a bigger blow to him than you might imagine, for reasons that allow me to dispense with a myth about Einstein and general relativity that has always bothered me. It is commonly assumed that Einstein worked in isolation in a closed room for years, using pure thought and reason, and came up with his beautiful theory, independent of reality (perhaps like some string theorists nowadays!). However, nothing could be further from the truth.

Einstein was always guided deeply by experiments and observations. While he performed many "thought experiments" in his mind and did toil for over a decade, he learned new mathematics and followed many false theoretical leads in the process before he ultimately produced a theory that was indeed mathematically beautiful. The single most important moment in establishing his love affair with general relativity, however, had to do with observation. During the final hectic weeks that he was completing his theory, competing with the German mathematician David Hilbert, he used his equations to calculate the prediction for what otherwise might seem an obscure astrophysical result: a slight precession in the "perihelion" (the point of closest approach) of Mercury?s orbit around the Sun.

Astronomers had long noted that the orbit of Mercury departed slightly from that predicted by Newton. Instead of being a perfect ellipse that returned to itself, the orbit of Mercury precessed (which means that the planet does not return precisely to the same point after one orbit, but the orientation of the ellipse shifts slightly each orbit, ultimately tracing out a kind of spiral-like pattern) by an incredibly small amount: 43 arc seconds (about 1?100 of a degree) per century.

When Einstein performed his calculation of the orbit using his theory of general relativity, the number came out just right. As described by an Einstein biographer, Abraham Pais: "This discovery was, I believe, by far the strongest emotional experience in Einstein?s scientific life, perhaps in all his life." He claimed to have heart palpitations, as if "something had snapped" inside. A month later, when he described his theory to a friend as one of "incomparable beauty," his pleasure over the mathematical form was indeed manifest, but no palpitations were reported.

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