WHY IS THERE SOMETHING RATHER THAN NOTHING?

In the beginning, according to the standard picture of cosmology, was the ‘inflationary vacuum’. It had a super-high energy density and repulsive gravity, causing it to expand. The more of it there was, the greater the repulsion and the faster it expanded. In common with all things ‘quantum’, this vacuum was unpredictable. At random locations, it decayed into ordinary, everyday vacuum. The tremendous energy of the inflationary vacuum had to go somewhere. And it went into creating matter and heating it to a blisteringly high-temperature – into creating big bangs. Our Universe is merely one such Big Bang bubble in the ever-expanding inflationary vacuum.

Remarkably, this whole process could have started with a piece of inflationary vacuum with a mass equivalent to a bag of sugar. And, conveniently, the laws of physics – specifically, quantum theory – permit such matter to pop into existence from nothing. Of course, the next obvious question now is: where did the laws of physics come from?

In 1918, German mathematician Emmy Noether shed light on this. She found that the great conservation laws are mere consequences of deep symmetries of space and time – things that stay the same if our viewpoint changes. A striking property of such symmetries is that they are also symmetries of the void – of an entirely empty Universe. So maybe the transition from nothing to something was not such a big deal. Maybe it was simply a change from nothing to the ‘structured’ nothing of our galaxy-filled Universe. But why did the change happen? The American physicist Victor Stenger pointed to the fact that, as the temperature drops, water turns into structured water, or ice, because ice is more stable. Could it be, he speculated, that the Universe went from nothing to ‘structured nothing’ because structured nothing is more stable?