A team of scientists at the University of Colorado in Boulder discovered an impenetrable belt protecting Earth, located about 7,200 miles above our planet, that prevents the most energetic electrons from reaching its atmospheric area.
The shield was discovered in the Van Allen radiation belts, two rings of seething radiation that surround Earth, being filled with high-energy protons and electrons. They are held in place by Earth’s magnetic field. They swell and shrink according to incoming energy from the sun.
Being the first major discovery of the space age, these two energy rings were detected in 1958 by a team of scientists lead by professor James Van Allen at the University of Iowa with the aid of U.S. satellite Explorer 1. As the research project extended, scientists concluded that the size of the two belts can vary or they can even divide into 3 parts. Generally, the space assembly is composed of one inner and one outer belt, stretching about 25,000 miles above Earth.
Using NASA’s Van Allen Probes, launched in 2012, professor Dan Baker and his team discovered a shield between the two radiation belts, which blocks the ultra-fast electrons from reaching Earth’s atmosphere.
“It’s almost like theses electrons are running into a glass wall in space,” explained Baker.
The team tried to identify the possible scientific explanations of this phenomenon. They reached the conclusion that the newly discovered barrier can neither be caused by the Earth’s magnetic field, nor by human transmitters. One possible cause could be though the presence of some other space particles.
The Earth is also surrounded by a plasmasphere, a giant cloud of charged particles, stretching from 600 miles above our planet up to the outer Van Allen belt. The plasmaphere may generate a scattering effect on the outer belt, removing the electrons on the boundary from their place.
“The scattering due to the plasmacause is strong enough to create a wall at the inner edge of the outer Van Allen Belt.”, Baker said.
The study regarding the impenetrable belt appeared on Nature magazine, the Nov. 27, 2014 issue.