The math that describes nature can be simple, even elegant. Consider Einstein’s beloved *E* = *mc*^{2}. A mere three letters tell us that matter and energy are, essentially, the same. Heisenberg’s uncertainty principle, which sets limits on what we can know about reality at small scales, fits neatly on a coffee mug.

And then there’s the Standard Model. This sprawling equation fills half a page in 12-point type. It’s held together by “renormalization” — the mathematical equivalent of duct tape — and contains a bunch of arbitrary numbers with no pattern, filled in by hand to fit the results of experiments. It’s an awkward theory only a physicist could love.

But beauty isn’t everything. For all its ungainliness, the Standard Model just happens to be the best theory ever devised for answering a question humans have been asking for millennia: What is the universe made of?

“There’s a degree of ugliness to the Standard Model,” says Nobel laureate Steven Weinberg, one of its architects. “But I think an elegant theory is one which leaves you with a sense that something has been explained, and we’ve made real progress in explaining nature using the Standard Model.”

? The math that describes nature can be simple, even elegant. Consider Einstein’s beloved *E* = *mc*2. A mere three letters tell us that matter and energy are, essentially, the same. Heisenberg’s uncertainty principle, which sets limits on what we can know about reality at small scales, fits neatly on a coffee mug.

**Field Day**

You may have heard that matter is, at its smallest scales, made of tiny dots — electrons and such — called particles. According to the Standard Model, you weren’t told the whole truth.

“Particles are not very interesting,” says Weinberg. “If you’ve seen one electron, you’ve seen them all.”

Particles arise from something even more fundamental: fields. Fields are invisible and everywhere. You’ve encountered fields before, the last time you tried to push two magnets together. That uncanny pressure you felt came from magnetic fields pushing back. Fields behave like liquids and can ripple, like the surface of an ocean. When they form a wave, a particle is born.

In the 1940s, physicists put the finishing touches on a theory that cast the electromagnetic force as quantum fields: quantum electrodynamics (QED). It suggested that every electron is a ripple in the same electron field, and every particle of light is a ripple in a photon field.

Ripples in one field can, like a gust of wind that creates waves in a lake, set off ripples in the other field. Understanding how electron and photon fields play together can explain not only the electromagnetic force and the interaction of charged particles, but also how light interacts with matter. It may sound crazy, but QED has passed every test with flying colors.