Belts that are sources of intense radiation surrounding the earth, consisting of high-energy charged particles trapped in the earth’s magnetic field, within which they follow roughly helical paths. They were discovered in 1958 by James Van Allen (1914–2006) as a result of radiation detectors carried by Explorer satellites. The lower belt, extending from 1000 to 5000 km above the equator, contains electrons and protons, while the upper belt, 15 000–25 000 km above the equator, contains mainly electrons.
Van Allen belts.
Two belts of high-energy, charged particles trapped by the Earth’s magnetic field within the magnetosphere. The inner belt starts at an altitude of about 800 km and reaches a maximum intensity at about 2000 km. The outer belt reaches a maximum intensity at between three and four Earth radii (18 000–25 000 km). Although commonly referred to as ‘radiation belts’, they contain particles, not radiation. Their presence was predicted by James Alfred Van Allen (1914–2006).
- ACE
- ace
- acellular
- acenaphthene
- acentric
- acentric factor
- acetabulum
- acetaldehyde
- acetaldol
- acetals
- acetamide
- acetanilide
- acetate
- acetate process
- acetic acid
- acetic anhydride
- acetoacetic acid
- acetoacetic ester
- acetone
- acetone–chlor–haemin test
- acetonitrile
- acetophenone
- acetylacetonato
- acetylating agent
- acetylation