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May 15, 2017

A banana is a good source of fiber, vitamin C, manganese, and a host of other goodies. It’s also a good source of antimatter. That’s because a banana contains a tiny amount of a radioactive form of potassium. As the element 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 appears to be quite 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 by thunderstorms.

Antimatter is also produced by the decay of radioactive elements, like the potassium in bananas. Antimatter from this type of decay 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: as a power source for starships. And it would be the most efficient power source around. The problem, though, is that making the stuff is extraordinarily expensive: trillions of dollars for a single gram. So we’re not likely to go warping around the galaxy in antimatter-powered ships anytime soon.

More about antimatter tomorrow.


Script by Damond Benningfield

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