# What Is Antimatter ?

in science •  last year

Everyone knows that the whole world is made of matter , the stars the planets , water , rocks , me and you , we are all made of matter . But what's antimatter ? Antimatter is a material composed of antiparticles . Every particle we know has an antiparticle that is identical to its particle but with the opposite charge . That mean antiproton ,  is the antiparticle of the proton , and the positron or antielectron is the antiparticle of the electron , and so on ... Since matter and antimatter have opposite charge , the antielectron would be positively charged because the electron is negatively charged , and the same for all particles , proton is positive while antiproton is negative .

## What happen when matter and antimatter meet ?

Let's simplify it to basic mathematics . The equation x2 = 4 has two solutions : +2 and -2 , and when they meet they disappear leaving a 0 . The same is for matter and antimatter , they have the same mass and the same properties but with different charges , and when they meet they annihilate leaving a burst of light caused by the energy of E=mc2

## History of Antimatter

The British physicist Paul Dirac first predicted the presence of antimatter when he was trying to combine the theory of relativity with quantum mechanics . And in August 2, 1932 Caltech physicist Carl Anderson discovered the positron , which is the antiparticle of electron (antielectron) ,  it was the first particle of antimatter to be identified  , for which he won the Nobel Prize for Physics in 1936

## How Carl Anderson discovered the positron ?

Carl Anderson built a cloud chamber , his goal was to know the composition of cosmic rays ( Cosmic rays are high-energy radiation that can produce secondary particles when it meets the earth atmosphere ) . So  Anderson placed a magnet , to know charge of particle that pass in , and he placed a lead plate to slow down the particle that pass  through  , so he was able to take a photograph of the tracks taken by cosmic ray particles .  The curve of the trajectory indicated that the particle was positively charged , but it was less massive than a proton , it is positively charged but it cannot be a proton , so what is that particle ? Physicists  thought  they discovered a new particle , a positively charged electron and gave it the name " positron " . But Anderson realized that the positron is the same as electron but with opposite charge , and he knew it was an antiparticle that Paul Dirac had predicted in 1931 .