Scientists have discovered an invisible shield roughly 7,200 miles above Earth that blocks so-called “killer electrons,” which can fry satellites and degrade space systems during intense solar storms. (Illustration by Andy Kale, University of Alberta.)
It sounds a plot ripped directly from science fiction … but it’s real: Earth has a force field-like natural shield that protects the planet — and us all — from killer space electrons.
Yes, KILLER SPACE ELECTRONS. Just in case you didn’t have enough to worry about at night. These particles thrash about in a cosmic mosh pit around at near-light speed, battering satellites, damaging space systems, threatening astronaut safety and even messing up your GPS from time to time.
But fear not. Shields are up.
Shields up, Scotty! (AP Photo/Paramount Pictures, Elliott Marks)
“It’s almost like theses electrons are running into a glass wall in space,” said the study’s lead author, Daniel Baker, director of (LASP). “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.”
Baker’s team discovered the barrier — which hangs out at about 7,200 miles altitude on the inner edge of the outermost of the two Van Allen radiation belts — keeps these superfast electrons from reaching Earth’s atmosphere.
The Van Allen belts are dual zones of highly-charged particles that encircle the planet. The radiation within creates something analogous to Earth weather … but in space. The inner belt extends between 1,000-8,000 thousand miles above the equator; the outer belt extends about 12,000-25,000 miles above the equator. (A third belt that sometimes appears was discovered in 2012 by NASA probes.) The belts are held in place by Earth’s magnetic field, and they swell or shrink in response to solar activity.
A cutaway model of the radiation belts with the 2 Van Allen Probes satellites flying through them. The radiation belts are two donut-shaped regions encircling Earth, where high-energy particles, mostly electrons and ions, are trapped by Earth’s magnetic field. (Click to enlarge.) (Credit: NASA)
in the form of blackouts and communication system mishaps, among others. However, travel through these belts can cause absolute havoc, so extra precautions must be taken to shield astronauts and equipment from their radiation. Case in point: , which is scheduled to launch on its first Experimental Flight Test on Dec. 4, will twice fly through the lower Van Allen belt on its 4 hour, 24 minute flight. Both times cameras will be turned off, and there are concerns that computer equipment on board will be affected.
But now? Baker’s discovery could potentially 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 explained. “Practically and specifically 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. () Science collected from the probes’ instruments is rapidly changing our understanding, including the shape, size, and time behavior of the Van Allen radiation belts, Baker said.
“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.”
A paper on this subject is published in the Nov. 27 issue of .
