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Matter and antimatter

We see the world around us stones, bricks, earth, wood, plastic, living things and so on. All these are made of atoms and the atoms themselves are made of protons, neutrons and electrons.

This all changed with the discovery of a particle by Carl Anderson in 1932 which he called the positron. The positron is a particle of antimatter and it was the first known particle of antimatter to be found. It has the same mass as an electron but a positive charge.

Since then many other antiparticles have been discovered in fact all the known particles have their own antiparticles for example protons and antiprotons. We are not sure how much antimatter there is in our Universe and we don't really know why there is the amount that there is. Some people have suggested that when out Universe was form e another Universe made of mostly antimatter was created at the same time. If it was we must hope that it never collides with our Universe!


We can make antimatter on a very small scale a high-energy gamma ray passing close to the nucleus of a heavy atom can turn into two particles an electron (matter) and a positron (antimatter).

When a particle meets an antiparticle they destroy each other producing a flash of energy usually gamma rays. Electrons and positrons annihilating each other have been seen in the lab.



However if we could do this on a large scale the results would be catastrophic.

 

If you were to meet your 'anti-self' (yourself from a Universe of antimatter) then you would destroy each other with a huge flash of energy about as much as that produced by a severe earthquake!

 

A VERSION IN WORD IS AVAILABLE ON THE SCHOOLPHYSICS USB
 
 
 
© Keith Gibbs 2020