This question has puzzled philosophers for at least 300 years, ever since Gottfried Leibniz wrestled with it. Leibniz postulated that “nothing” was a simpler state than “something;” therefore it was natural that there should be nothing. However, since there is something (because, if there were nothing, he and we would not be here to ask the question), there must be a creator in there somewhere. With the current state of humanity, some would argue that Leibniz’s value judgment that something is better than nothing, old Gottfried was on to something (no pun intended). His question is profound and poses a challenge for deists and atheists alike: the necessity to explain creation out of nothing.
Let’s take a closer look at the “something.” You can get something in two flavors, light (radiation) and matter. In physics, light and matter “particles” are called bosons (light) and fermions (matter) after the two scientists who described their properties statistically (we will soon see that nothing is real, it is just a matter of probability). Fermions are aloof and individualistic. In terms of their probability, no two fermions are exactly alike. Bosons, on the other hand, are promiscuous. Bosons are the carriers of all the forces in nature. Photons, which carry light, can have the same energy and occupy the same space.
The universe has far more bosons than fermions and this discrepancy bothers physicists. After all, what little matter (fermions) there is was enough to make billions of galaxies and stars. Now if the number of fermions is only a small fraction of the number of bosons, imagine how many bosons (or, how much energy) there must be.
In addition to this puzzle, in the 1920s Paul Dirac, an English physicist working on the new theory of quantum mechanics, made a prediction for the existence of antimatter. Dirac solved the fundamental equation that explains the behavior of the electron and found two solutions. One solution involved the square root of a positive number, the other included the square root of the same negative number. Generations of college calculus students have grappled with this notion of the square root of a negative number, since any two numbers that are either both positive or negative, when multiplied together yield a positive number. In mathematics there is the imaginary number i, which is the square root of negative one (i x i = -1). Many math problems have these two solutions, one real and one imaginary, but when it comes to “real world” solutions, the imaginary solution is usually discarded. Rather than discard it, Dirac left it in his paper.
Four years later Carl Anderson was watching cosmic rays in his cloud chamber. A cloud chamber is where scientists can observe particles interact with a supersaturated vapor. By applying a magnetic field to the chamber the particle can be made to curve. The vapor trail left by the particle registers the passage of the particle. Anderson was observing electrons and noticed that, while most of the vapor trails curved in the expected direction, a few curved in the opposite direction. This meant that a few particles had the same mass as electrons but had the opposite charge, positive rather than negative. Anderson called these “positrons” for positive electrons. In the context of Dirac’s work, positrons are the particles predicted by the solution to the problem that involves the imaginary number.
It turns out that the existence of antimatter is far less than the existence of matter, which is a good thing. If the number of fermions of the antimatter variety were roughly equal to the number of fermions of the matter variety, it is likely there would be “nothing” rather than “something.” While this difference should be comforting to us in the sense that we need not fear being annihilated by our antimatter counterpart, to scientists this discrepancy is troubling.
In terms of Einstein’s E = mc2 that shows how energy and matter are interchangeable, matter and antimatter are on equal footing. Quantum theory predicts that every particle has an antiparticle. But antimatter particles don’t survive very long while matter particles do. In Dan Brown’s novel Angels and Demons, the bad guys steal half a gram of antimatter and high-tail it to Rome to make a bomb. The mark of good fiction is to cause “the willing suspension of disbelief,” that is, to make the reader willing to ignore the little voice in her head that says “that would never happen.” By that criterion, Brown is a master of fiction because his premise, that half a gram of antimatter could exist, is outrageous. At current production rates it would take 10 million years to create half a gram of antimatter. The cost to create one-billionth of a gram of antimatter is about a billion dollars.
To understand particle physics and the extreme rarity of antimatter we need to understand, at least a little bit, what physicists call the Standard Model. To do this, we have to lay some groundwork that includes a Laplace transformation of a Calabi-Yau manifold across a chronosynclastic infindibulum. I made that last part up but that’s the kind of language particle physicists speak.