The Earth is mysteriously being protected in space by a powerful yet invisible shield surrounding the planet similar to the "force fields" in "Star Trek" movies, scientists have revealed.
In a study published in the Nov. 27 issue of Nature, Professor Daniel Baker from the University of Colorado Boulder said the shield is located some 7,200 miles above Earth and is made up of high-energy electrons and protons.
Baker said the invisible barrier blocks "killer electrons" produced by solar storms from penetrating deep into the Earth's atmosphere. He said these electrons whipping around the planet at near-light speed can be destructive and have been known to threaten astronauts, burn satellites and damage space systems.
If these "killer electrons" hit Earth on a massive scale, they could knock out power grids, drastically change the planet's climate and cause cancer to many people, scientists said.
"It's almost like theses electrons are running into a glass wall in space," said Baker, the lead author of the study. "Somewhat like the shields created by force fields on Star Trek that were used to repel alien weapons, we are seeing an invisible shield blocking these electrons. It's an extremely puzzling phenomenon," he said.
John Foster from the Massachusetts Institute of Technology described the phenomenon as "very unusual, extraordinary, and pronounced."
"What this tells us is that if you parked a satellite or an orbiting space station with humans just inside this impenetrable barrier, you would expect them to have a much longer lifetime. That's a good thing to know," he said.
The shield was discovered in the Van Allen radiation belts, which are two doughnut-shaped rings above Earth filled with high-energy electrons and protons. Scientists say the invisible rings are held in place by Earth's magnetic field, adding that they swell and shrink in response to incoming energy disturbances from the sun.
The Van Allen radiation belts were first discovered in 1958. However, scientists only recently discovered the two belts, an inner and outer belt extending up to 25,000 miles above the Earth.
Last year, Professor Baker discovered a third transient "storage ring" located between the previously known inner and outer Van Allen radiation belts. This belt is different because it seems to come and go as space weather changes, Baker said.
Baker said he and his team are trying to look for scenarios that could create and maintain such a protective shield in space.
They wonder if this is being caused by Earth's magnetic field lines or by radio signals from human transmitters on Earth. But these two scenarios are highly unlikely, Baker said.
"Nature abhors strong gradients and generally finds ways to smooth them out, so we would expect some of the relativistic electrons to move inward and some outward," he said. "It's not obvious how the slow, gradual processes that should be involved in motion of these particles can conspire to create such a sharp, persistent boundary at this location in space."