This is an artist's conception of the Earth and its radiation
belts. Click on image for full size The Discovery of the
Radiation Belts The belts of trapped radiation above the Earth's
atmosphere, but within the magnetosphere, were first detected by
James Van Allen in 1958. Therefore these belts are also known as
Van Allen Belts. When Sputnik I, the first spacecraft, was
launched in 1957 by the Soviet Union, the Americans were anxious
to respond. The Americans wanted to not only launch a satellite,
but to learn something new! Dr. James Van Allen had already been
exploring the upper atmosphere of the Earth with balloons that
could obtain information about radiation levels in the
atmosphere. Van Allen and his team placed a Geiger counter and
an altimeter on Explorer I, the first American spacecraft, to
take radiation readings at different altitudes. During the
flight, radiation levels seemed to increase and then suddenly
drop to zero and then again to increase, then suddenly drop to
zero. What the team soon real