Shields up! A team from the University of Colorado Boulder have discovered an “invisible shield” approximately 7,200 miles above Earth. The shield reportedly blocks so-called “killer electrons” that travel around the planet at near-light speed and can potentially threaten astronauts, fry satellites and damage electrical systems during solar storms.
As some of you might know, the Earth is surrounded by the Van Allen radiation belts, two doughnut-shaped rings that are filled with high-energy electrons and protons. The belts periodically swell and shrink in response to incoming energy disturbances from the sun. However, the ‘shield’ was discovered within the belts by UCB’s Professor Daniel Baker and his team.
The discovery was made thanks to the twin Van Allen Probes launched by NASA in 2012, which found a third, transient “storage ring” between the inner and outer Van Allen belts that seems to come and go with the intensity of space weather. This belt is roughly 7,200 miles above the Earth and appears to block the ultrafast electrons from moving deeper towards Earth’s atmosphere.
“It’s almost like theses electrons are running into a glass wall in space,” said Professor Baker. “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.”
The shield also seems to be impenetrable, as the highly charged electrons don’t do what the team thought they would do, which is drift towards the atmosphere where they would be wiped out by air molecules. Instead, they are held in the upper atmosphere.
“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,” said Baker. “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.” The scientists are researching how the shield could have potentially been formed as all their current theories seem to have no explanation!