“Cosmic Ray” Belt Around Earth Verified

Cosmic_rays_hit_earth Italian researchers, led by Piergiorgio Picozza from the University of Rome, using data from the satellite PAMELA have proven that theories showing there ought to be a ring of antiprotons, called the Van Allen radiation belt, encircling the Earth due to cosmic rays colliding with nuclei in the upper atmosphere are correct.

Physicists have theorized that the constant stream of cosmic rays generated by the sun and other little understand sources must produce a shower of sorts of smaller particles when they collide with other nuclei in the Earth’s upper atmosphere and break apart. Some of those smaller particles have been assumed to be antiprotons, many of which would be annihilated when colliding with particles of ordinary matter.

Because of the earth’s magnetic field, physicists suggest there actually exist two such radiation belts covering the planet, the outer and inner. The outer belt should be comprised of lighter particles such as positrons, while the inner belt would consist of much larger particles, such as antiprotons because the force of gravity would be able to hold them in.

The researchers used the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) Russian made satellite, which has a cosmic ray detector onboard and regularly passes through a particularly dense section of the Van Allen belt called the South Atlantic Anomaly to test the theory.

Over a period of 850 days, between July 2006 and December 2008, sensors onboard PAMELA detected 28 antiprotons, which the team says, is about three times more than would be found from a random sample of the solar wind, and constitutes the most abundant source of antiprotons ever seen near the Earth.

The Daily Galaxy via http://arxiv.org/abs/1107.4882 and physorg.com


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