Mysterious Ring of Radiation Around Earth Explained

A new study has revealed the source of an unusual ring of radiation that developed last September, encircling the Earth for a month before disappearing as mysteriously as it appeared.

The ring's presence was first reported in February, uprooting the belief the Van Allen radiation belts -- first discovered in 1958 -- are only ever comprised of two rings -- one consisting of high-energy electrons and positive ions and the other simply of high-energy electrons. However, besides reporting on the presence of the new, short-lived ring, the study offered little in the way of explanation.

In the new paper, however, researchers from the University of California, Los Angeles report their successful attempt at modeling and explaining the third ring, demonstrating that its extremely energetic particles are driven by physics far different than those observed in the other two.

"In the past, scientists thought that all the electrons in the radiation belts around the Earth obeyed the same physics," Yuri Shprits, a research geophysicist with the UCLA Department of Earth and Space Sciences and study lead, said in a statement. "We are finding now that radiation belts consist of different populations that are driven by very different physical processes."

Ultra-relativistic electrons like the ones that comprised the third ring are especially hazardous, capable of penetrating through the shields built around even the most expensive and valuable space satellites, Shprits notes.

"Their velocity is very close to the speed of light, and the energy of their motion is several times larger than the energy contained in their mass when they are at rest," Adam Kellerman, a staff research associate in Shprit's team, said, explaining that the "distinction between the behavior of the ultra-relativistic electrons and those at lower energies was key" to the study's success.

Ultimately, understanding the nature of the Van Allen belts is necessary to protecting people and equipment from their effects, according to the researchers. And, as the new study shows, they "can no longer be considered as one consistent mass of electrons," Shprits said. Instead, they "behave according to their energies and react in various ways to the disturbances in space."