Matter vs. Antimatter II

Antimatter sounds exotic, and in one way, it is: it’s quite rare. Although a lot of it may have been created in the Big Bang, most of it was cancelled out by interactions with normal matter. As far as anyone can tell, that left only a tiny smattering of antimatter, along with a bit that’s been created since then in various natural reactions.

But in most ways, antimatter isn’t exotic at all — it’s just like normal matter. The only difference is its electric charge. A particle of antimatter has the opposite charge from its normal-matter counterpart. So when matter and antimatter meet, they annihilate each other.

In laboratory experiments, physicists have measured the electric charge of the positron, which is the antimatter counterpart of the electron. And they’ve found that its charge is equal and opposite of that of the electron to better than one part in a billion.

Today, physicists are trying to see if the effects of gravity are the same on antimatter as on normal matter. One of those experiments, at the CERN accelerator in Europe, is getting under way this spring. It’s not an easy measurement to make. The experiment must create a charged atom of antimatter, keep it from reacting with normal matter, strip away its electric charge, then drop it to see if it “falls” in the same way as normal matter.

But so far, everything that scientists have found shows that antimatter looks and behaves just like normal matter — as long as you don’t touch it.

Script by Damond Benningfield