MYSTERIES OF THE UNIVERSE

In the last decade, we’ve taken photos of a black holes, peered into the heart of atoms and looked back at the birth of the Universe. And yet, there are yawning gaps in our understanding of the Universe and the laws that govern it. These are the mysteries that will be troubling physicists and astronomers over the next decade and beyond

- MARCUS CHOWN

1 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?