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The Question
(Submitted March 30, 1998)
Could you tell me who created antimatter, and who first studied it?
The Answer
Antiparticles are just a set of sub-atomic particles with some properties
opposite to those of another set of particles with which we are more
familiar. For example, the positron is the antiparticle equivalent of the
electron. When a particle and its antiparticle meet, they annihilate with
the release of a lot of energy.
Antiparticles will have been produced in the big bang which initiated the
universe. In fact, most models of the big bang produce as much antimatter
as ordinary matter, which is not easy to reconcile with the largely matter
universe we see around us. Antiparticles are also produced in the
transformation and interaction of other particles. For instance, a proton
can sometimes produce a neutron and a positron.
The English physicist Paul Dirac first proposed the existence of
antiparticles, when he derived equations which had solutions corresponding
to both normal and antimatter particles. The American physicist Carl
Anderson made the first detection of antimatter when looking at cosmic ray
tracks in 1932 and noting that some tracks bent the 'wrong way' in a
magnetic field.
Paul Butterworth
for the Ask a High-Energy Astronomer team
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