Scientists discovered an invisible protective shield approximately 7,200 miles above Earth’s surface that is protecting us from harmful, ultra-fast electrons flying close to the speed of light.
It may sound like a concept out of Star Trek, however this mysterious protective barrier isn’t science fiction. The findings, published in the journal Nature, could help scientists better understand the complex dynamics of Van Allen radiation belts.
— Steve Warner (@darkweekend) November 27, 2014
The Van Allen radiation belts, first discovered in 1958, are two donut-shaped rings of energetic particles circling Earth up to roughly 25,000 miles above the surface, and are held in place by the planet’s magnetic fields reports the Los Angeles Times. Scientists have discovered that there appears to be an inner zone of high-energy protons and an outer zone of high-energy electrons. These belts are thought to be fed by cosmic rays and the solar wind – they can swell or shrink over time in response to changes in weather in space.
The high-energy “killer electrons” in the belt can cause trouble for the sensitive electronics of orbiting satellites and even potentially harm the health of astronauts in space. So it begs the question, how is it that these high-speed particles traveling faster than 100,000 miles per second, don’t regularly ause problems on Earth?
To find this answer, scientists studied the belt using NASA’s twin Van Allen probes. As it turns out, there seems to be a sharp cutoff of high-energy electrons 7,200 miles above Earth – almost as though they were hitting a protective shield, lead author Daniel Baker, director of the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics, said in a statement.
“The presence of such a clear, persistent and seemingly impenetrable barrier to inward transport of ultrarelativistic electrons at this very specific location presents a substantial puzzle,” the study authors wrote.
The cutoff took scientists by surprise – they had expected to see a smooth, natural transition. Previous theories suggested that the magnetic fields might be holding the electrons in place, or that human-generated radio signals from the ground were stopping them. But now, given what scientists are seeing these theories are null.
The researchers believe it could have to do with electrically charged cold gas in a zone called the plasmasphere, which begins around 600 miles above Earth and stretches for thousands of miles into the outer, electron-dominated zone in the Van Allen belt.
Impenetrable Protective Shield Discovered 7200 Miles Above Earth