[NCDXA] Third radiation belt discovered around Earth

[Robert Lepelletier]

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

 

Third radiation belt discovered around Earth

 

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

 

A third belt can sometimes appear, the radiation is shown here in yellow, with green representing the spaces
between the belts Photo: NASA/Rex Features

 

By Nick Collins, Science Correspondent
4:20PM GMT 01 Mar 2013

 

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.
John Grunsfeld, NASA’s associate administrator for science, said: "The fantastic new
capabilities and advances in technology in the Van Allen Probes have allowed scientists to see
in unprecedented detail how the radiation belts are populated with charged particles and will
provide insight on what causes them to change, and how these processes affect the upper reaches
of Earth’s atmosphere."

 

The outer of the two Van Allen belts had previously been seen as one blurry ring, but high
resolution images taken by the Relativistic Electron Proton Telescope instrument on board the
probes revealed two separate rings with a clear space in between. The new belt was visible for
four weeks before being destroyed by a shock wave released by the Sun.


Nicky Fox, Van Allen Probes deputy project scientist at the Johns Hopkins University, said:
“We thought we knew the radiation belts, but we don’t. The advances in technology and
detection made by NASA in this mission already have had an almost immediate impact on basic
science."

 


 

  		 	   		  
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