Invisible Shield Protects Earth from 'Killer Electrons'

An invisible shield hovering some 7,200 miles above our atmosphere is protecting Earth from "killer electrons" with the power to harm astronauts, fry satellites and degrade space systems during solar storms, new research describes.

"It's almost like theses electrons are running into a glass wall in space," Daniel Baker, the study's lead author, said in a statement. "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."

With dangerous particles whipping around space at near-light speeds (approximately more than 100,000 miles per second), it's lucky that this Star Trek-like force field is there to protect us.

The barrier was discovered in the Van Allen radiation belts, two rings above Earth held in place by Earth's magnetic field. Discovered in 1958, it's regarded as one of the first significant discoveries of the space age. It was at the edges of this belt where scientists first noticed a peculiar phenomenon - particles just stopping in mid-flight.

Scientists had speculated that interference from Earth's magnetic field or man-made radio waves were responsible, but now researchers suggest that the plasmasphere is playing a role. The plasmasphere is a giant cloud of cold gas that begins 600 miles above Earth and stretches out into the radiation belts. It's possible that the plasma somehow scatters the electrons at the barrier, but more research is needed to confirm this theory.

"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," Baker 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."

The findings were published in the journal Nature.

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