What is antimatter, and what are some of it's properties?

I am having trouble understanding that antimatter travel backward in time? Can someone explain to me (in an easy way that an 8th grader would understand) how this is logically possible? Please include any helpful websites that I could visit.


1 Answer
Jul 14, 2017

Antimatter is matter made up from particles with the opposite charge to normal matter.


Most particles have an anti-particle. In particular charged particles have an anti-particle with the opposite charge. Some uncharged particles are their own anti-particle.

Normal matter consists of mainly protons, neutrons and electrons. The proton is positively charge and the antiproton is negatively charged. The electron is negatively charged and the antielectron, or positron, is positively charged. The neutron and the anti-neutron have neutral charges.

Antimatter is made up of antiprotons, antineutrons and positrons.


When a particle meets its antiparticle they annihilate each other to form photons.

When the universe was formed there should have been equal amounts of matter and antimatter. For reasons unknown, matter was more dominant. Although it is possible that there may be antimatter galaxies.

We don't know much about the properties of antimatter. We do know that the antiparticles exist and behave in the same way as the normal particles except for charge. It is now possible to form small quantities, upt to a few hundred atoms of anti-Hydrogen, in the laboratory and more experiments can now be conducted.

Richard Feynman showed that mathematically a positron is indistinguishable from an electron travelling backwards in time. This doesn't mean that antimatter travels backwards in time, it is just a consequence of the mathematics.