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What is antimatter?

You know that matter, and therefore everything you see, is made out of 3 different types of "brick" that physicists call particles: electrons, protons and neutrons.

These particles have been mysterious for quite some time: although physicists knew they existed, they knew very little about them. In physics, you can say you "know" something when, among other proprieties ,you can predict and describe the way it behaves. You know that a stone will fall if it's not held properly. Physicist can describe how it falls and predict exactly where it will touch the ground using mathematical formulas.

But physicists couldn't predict anything about the electron! Until a very smart guy named Paul Dirac thought about it: he found a very simple way to describe the proprieties and behavior of electrons, but... there was something curios about it!

His description would only work if the electron had a "twin" particle, identical to it but with an opposite electric charge. It would be just like its mirror image!
He called it an antielectron or POSITRON. Of course, the same would be true for any existing particle (proton and antiproton, neutron and antineutron).

(What is antimatter? - page 1of 6)
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