Anti Matter

November 28, 2010
  • Particle Physics
  • Physics

In a result that is surprisingly similar to a plot point in a Dan Brown novel, scientists at CERN recently announced in a paper appearing in the illustrious Nature magazine that that they had captured an antimatter molecule and stored it for a long period of time (about 1/10 of a second, which is very long by antimatter standards). The ALPHA experiment reported that it had managed to temporarily confine 38 atoms of anti-hydrogen, which is a bound state of an anti-proton and an anti-electron (or positron). The ALPHA experiment is separate from the experiments that work on the LHC, the large accelerator located beneath CERN. ALPHA works with a smaller accelerator to collect anti-protons and uses natural radioactive substances to create the anti-electrons, which it then combines into anti-hydrogen.

Antimatter, of course, is hardly science fiction. Weve knew about its existence throughout most of the 20th century. It was originally theorized by the great physicist Paul Dirac in one of the most bold predictions in the history of science. In 1928, Dirac discovered an equation which describes the quantum mechanical description of relativistic (fast moving) particles. But his equation yielded something else. Dirac realized that while his equation could be used to describe know particles (electrons, for example), it also required the existence of similar particles with the exact opposite charge. At this time, his work was completely theoretical. It was merely a way to have quantum mechanics work within Einsteins relativity. Yet from his equation alone, he theorized that there must be so-called antiparticles for all of the known particles that had been discovered by physicists. In 1932, Carol Anderson, while studying his cloud chamber, observed a particle that had the exact same properties as an electron, only with the opposite charge.

Positron

He dubbed this object the positron, and for his discovery he won the nobel prize in 1936. Dirac won the prize in 1933 for his overall contribution to physics, but certainly the correctness of his prediction of antimatter was a main reason he was given the award.