A shield, similar to that which repelled alien weapons from Star Trek’s starship Enterprise, is protecting us from ‘killer electrons’.
A team from the University of Colorado Boulder discovered it 7,200 miles above Earth, thanks to the Van Allen probes mission. At that height, electrons fly around the planet at near-light speed and have been “known to threaten astronauts, fry satellites and degrade space systems during intense solar storms.”
“It’s almost like theses electrons are running into a glass wall in space,” said Professor Daniel Baker, the study’s lead author.
“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 barrier to the particle motion was discovered in the Van Allen radiation belts, two doughnut-shaped rings above Earth that are filled with high-energy electrons and protons, said Baker, director of CU-Boulder’s Laboratory for Atmospheric and Space Physics.
Held in place by Earth’s magnetic field, the Van Allen radiation belts periodically swell and shrink in response to incoming energy disturbances from the sun. This current study is all part of a NASA program managed by the Goddard Space Flight Centre.
Impenetrable barrier, tough as nails
The shield is an unexpected discovery, positioned on the inner edge of the outer belt. And clearly, more research is needed. The scientists thought the highly charged electrons gradually drifted towards our atmosphere before breaking up amongst air molecules.
“But the impenetrable barrier seen by the twin Van Allen belt spacecraft stops the electrons before they get that far,” according to University of Colarado. The researchers investigated several scenarios that could create such a defensive barrier, with no clear answers yet.
“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.”
One scenario is a “hiss”, created by a plasmashere scattering the electrons around with “low frequency, electromagnetic waves”. The hiss sounds like white noise when played over a speaker, said Baker.
“I think the key here is to keep observing the region in exquisite detail, which we can do because of the powerful instruments on the Van Allen probes. If the sun really blasts the Earth’s magnetosphere with a coronal mass ejection, I suspect it will breach the shield for a period of time,” said Baker.
Earth shielding an attack image via Shutterstock
Buy your tickets now!