A banana is a good source of fiber, vitamin C, and many other goodies. It’s also a source of antimatter. That’s because a banana contains a tiny amount of a radioactive form of potassium. As it decays, it produces positrons, the antimatter counterpart of electrons. They’re no threat, though — there just aren’t enough of them.

Particles of antimatter have the opposite electric charge from normal matter. An electron, for example, has a negative charge, while a positron has a positive charge. When matter and antimatter meet, they annihilate each other, producing pure energy.

Antimatter is rare, but there is some. A tiny fraction of the cosmic rays that strike Earth’s atmosphere, for example, consists of positrons and antiprotons. There’s also evidence that positrons are produced in thunderstorms.

Antimatter is also produced by the decay of radioactive elements, like the potassium in bananas. Antimatter from these reactions is used in PET scans. And research suggests that antimatter could someday be used to treat tumors.

Of course, the most famous use of antimatter is fictional — a power source for starships. And it would be the most efficient power source around. The problem, though, is that the stuff is pricey: it would cost trillions of dollars to make a single gram. So we’re not likely to go warping around the galaxy in starships powered by antimatter anytime soon.

More about antimatter tomorrow.
 

Script by Damond Benningfield

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