Paul Dirac lectures at CERN
When a group of physicists entered the Main Auditorium, during the evening of 29 June, they felt they had opened a time portal.
An attentive audience, dressed in early 1900 costumes, were watching a lecture by the elusive Paul Dirac, presenting for the first time his famous formula on the blackboard. Paul Adrien Maurice Dirac (1902-1984) was a British mathematical physicist at Cambridge, and one of the "fathers" of quantum mechanics. When he first wrote it, in 1928, Dirac was not sure what his formula really meant. As demonstrated by Andersson four year later, what Dirac had written on the blackboard was the first definition of a positron, hence he is credited with having anticipated the existence of antimatter.
![](http://cds.cern.ch/record/1277689/files/icon-dirac-at-cern-by-sandra-hoogeboom_06(1)_image.jpg)
The actor John Kohl performs as Paul Dirac.
©Sandra Hoogeboom
See the video here.