It sounds like a plot ripped directly from science fiction: Scientists have discovered an invisible force field that shields the planet from a barrage of so-called “killer electrons” from space.

“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,” said the study’s lead author, Daniel Baker, director of the University of Colorado’s Laboratory for Atmospheric and Space Physics.

These electrons, which thrash about at near-light speed in a cosmic mosh pit of sorts, have been known to batter satellites with radiation and wreak havoc on space systems of all kinds.

But fear not: Shields are up.

“It’s almost like these electrons are running into a glass wall in space,” Baker said.

The electrons are found in the Van Allen belts — dual zones of highly charged particles that encircle the planet.

The “force field” barrier is at about 7,200 miles altitude on the inner edge of the outermost of the two Van Allen radiation belts, keeping the superfast particles from reaching Earth’s atmosphere.

Space exploration and travel through the Van Allen belts requires extra precautions to shield astronauts and equipment from the radiation.

This discovery, however, could change how spacecraft are retrofitted for radiation protection.

“This means that for space systems operating closer to Earth … there are virtually none of these immensely penetrating and dangerous high-energy electrons,” Baker said. “This means that spacecraft above 7,200 miles altitude will generally see quite high fluxes of high-energy radiation; below such altitudes, the energetic electron environment is much more ‘benign’ than we previously had suspected.”

In 2012, NASA launched two probes to study the Van Allen belts. Data collected from the probes’ instruments are rapidly changing our understanding — including the shape, size and time behavior — of the Van Allen radiation belts.

“Things we thought in the past were true simply are not correct,” Baker said. “It is for this reason that I cite the great American philosopher Yogi Berra, who said, ‘You can observe a lot just by looking.’ Our new instruments allow us to look in ways we never could before.”

The discovery was announced Wednesday, and a paper on the subject is published in the current issue of Nature.

Laura Keeney: 303-954-1337, lkeeney@denverpost.com or twitter.com/LauraKeeney