van Allen, Belts of

The Van Allen belts are radiation belts which surround the Earth. They carry the name of the American physicist James Alfred Van Allen (who died in 2006), to whom their discovery is owed. Van Allen dreamed up the scientific programme of the first American satellite, Explorer 1, launched in February 1958. It was the instruments on board that allowed for the discovery that the Earth is surrounded by a belt of radiation. This discovery is considered as the first major scientific discovery of the space age, the data supplied by Sputnik-1 being more of an anecdotal nature.

The Van Allen belts are of two types. The first (between an altitude of 700 and 1000km) is composed of protons emanating from the solar wind and captured by the Earth’s magnetic field.

The second (between an altitude of 13,000 and 65,000km) is composed of electrons.

Van Allen Ceinture EN