Third radiation belt discovered around Earth

A previously unknown belt of radiation surrounded Earth for several weeks last year, Nasa scientists have discovered.

Since 1958 scientists have known that Earth is circled by two doughnut-like rings of trapped charged particles called the Van Allen radiation belts.

But now a third, temporary belt has been discovered after, appearing for a month last year before being dispersed by a shock wave released by the Sun.

Astronomers hope to discover how often the third belt forms and learn more about the behaviour of all three belts, which can damage communications and GPS satellites and expose astronauts to extra doses of radiation.

The Van Allen belts, named after their discovered James Van Allen, are known to periodically swell as a result of space weather and solar storms but the exact cause is poorly understood.

The new observations, published in the Science journal, were made by Nasa's twin Van Allen probes which were launched on August 30 bearing hi-tech particle detection equipment.

source @ http://www.telegraph.co.uk/science/space/9902765/Third-radiation-belt-discovered-around-Earth.html