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KU mathematician gets a handle on the shape of a proton

by Roger Martin

The proton -- one of those spherical things buzzing around inside the atom -- is having an identity crisis.

A quick physics review. The simplest atom, hydrogen, is just ONE electron spinning around ONE proton. Get rid of the electron and you can actually taste the proton. Vinegar and lemonade get their flavor from hydrogen atoms stripped of electrons.

Protons taste sour.

But the identity crisis of protons involves their shape not their flavor. It seems they may not be spherical after all. University of Kansas theoretical physicist John Ralston did some math a couple of years ago indicating the proton might be oblong. Or maybe have a hole in the middle, like a Lifesaver. Recently, Ralston's picture of the proton as out of round received some experimental support.

A team at Jefferson Laboratory in Virginia shot a high energy electron beam at a target full of protons. Then they studied the protons they knocked loose.

If a proton is round, it should be hard to flip over. But, Ralston says, when a proton isn't round, when it has a handle on it, so to speak, then it will flip more easily. And that's what happened in the experiment.

Before you get all worked up about the oblong proton, you should realize that the idea is still being pondered by physicists.And besides, even if the proton isn't a sphere, that leaves a whale of a lot of possibilities. These do not include a cube-shaped or egg-shaped proton, says Ralston -- though a hot-dog shape isn't out of the question.

Of course all the speculation about the proton's shape would cease if only we could see it directly. Which is tough. The proton is a hundred thousand times smaller than an atom. Nevertheless, Ralston's feverishly working on the mathematics of how to see a proton. He says that because of the nature of the equipment used in physics experiments, it may actually be easier to see a proton directly than to see a large molecule directly.

Today, in order to "see" molecules, scientists have to crystallize substances containing those molecules. And even then, determining their structure involves guesswork. "It's an absolute jigsaw puzzle," Ralston says, "You can come up with the correct structure but have it twisted the wrong way."

And so even as he theorizes about how to see the proton directly, he "agonizes" -- that's his word, not mine -- about how to see molecules directly. If that were possible, he says, "You could do everything on the planet. You could discover drugs, know how genes are regulated, answer every unknown question in biology just by looking directly at the molecules."

As we wait for that, here's my question: What earthly difference does it make if the proton is out of round?

Ralston answers by remembering Michael Faraday. Faraday was the guy who discovered the physical laws that made it possible to tame electricity. At one point, somebody asked, "Mike, why should we care? What are folks going to do with electricity anyway?" Faraday answered with a question of his own: "What use is a newborn baby?"

Right now, the oblong proton is Ralston's baby. If it survives -- well, let's just say it's an idea with all the potential of any newborn.