Where can antimatter be found?

Answer 1

Antimatter is found in small amounts inside cosmic rays, and also extremely small amounts are created within stars. However, scientists believe that there could be galaxies made of antimatter, or even entire universes.

Here on earth, we find antimatter being created as a result of a type of radioactive decay called beta plus decay. In that instance, a positron (an anti-electron) is ejected from an atomic nucleus as that nucleus transforms. Additionally, a gamma ray of sufficient energy passing close to an atomic nucleus may produce a positron-electron pair in what is called pair production. Those are the most common encounters we'll have with antimatter. We also see anti-protons being created and injected into accelerators like the Large Hadron Collider (LHC). In the LHC, protons and anti-protons are sped up as they circle the ring (in opposite directions) and then set on a collision course.

Answer 2

The modern theory of antimatter begins in 1928 by Paul Dirac. Dirac realised that his relativistic version of the Schrödinger wave equation for electrons predicted the possibility of antielectrons. These were discovered by Carl D. Anderson in 1932 and named positrons (a contraction of "positive electrons"). Although Dirac did not himself use the term antimatter, its use follows on naturally enough from antielectrons, antiprotons etc.

Answer 3

Physicist Paul Dirac developed a theory of nuclear reactions in 1928 which indicated that particles of matter such as protons and neutrons but with the opposite electrical charge ought to exist. So protons normally have a positive charge; there ought to exist particles of the same mass as protons but with a negative charge. Electrons are negatively charged; Dirac's theory indicated that something very much like an electron except positively charged ought to exist. Dirac won the Nobel Prize for Physics in 1933.

In 1932, Cal Tech researcher Carl Anderson found a "cloud chamber" particle which seemed to behave the way Dirac's theory had predicted.

Answer 4

The positron was first predicted theoretically, then discover about 5 years later in accelerator experiments.