The barrier, which comes and goes, is the result of very low frequency (VLF) communications, used to communicate with submarines deep below the surface of the ocean, interacting with space particles.
The barrier is created when VLF signals go high up into the atmosphere, forming what scientists call a "VLF bubble," which interacts with the inner edge of the Van Allen radiation belts, arcs around the planet full of charged particles created by solar wind.
Scientists say this could bode well for the Earth, as the barrier may protect against geomagnetic storms, the result of huge explosions from the sun called coronal mass ejections, that could potentially disable power grids and communication satellites.
Analysis of 1960s data indicates that the Van Allen radiation belt’s inner limit was much closer to Earth than it is today, as VLF signals were used much less frequently. This led scientists to posit that, if there were no VLF bubble, the radiation belt boundary would be much closer to Earth than it is, according to Newsweek.
"A number of experiments and observations have figured out that, under the right conditions, radio communications signals in the VLF frequency range can in fact affect the properties of the high-energy radiation environment around the Earth," Phil Erickson, one of the NASA scientists involved in the discovery, said in a statement.
NASA scientists say it’s possible that the radiation barrier could be used to remove excess radiation from the area surrounding Earth, and tests are planned to determine whether this is possible.