The Loh Down On Science

What NASA saw on September 2, 2012

NASA/Van Allen Probes/Goddard Space Flight Center

Two giant swaths of radiation, known as the Van Allen Belts, surrounding Earth were discovered in 1958. In 2012, observations from the Van Allen Probes showed that a third belt can sometimes appear. The radiation is shown here in yellow, with green representing the spaces between the belts.

Hey, fashionistas! You thought you knew your Van Allen belts!

This is Sandra Tsing Loh with the Loh Down on Science.

They're not fashion accessories. Van Allen belts are swaths of radiation—high-energy particles like electrons or protons.  Shaped like really big donuts, they surround the earth. 

Until very recently, we knew about just two rings.  One inner, one outer.

But last August, two NASA spaceships blasted into orbit and flipped on their super-sensitive sensors.  Lo and behold, the spacecrafts' instruments picked up signs of a third radiation belt forming out of the bigger, outer one.

Physicists suspect it formed after—get this—an interplanetary shockwave blew through! These shockwaves occur when the solar wind shifts dramatically. The solar wind is a stream of charged particles from the sun.

Alas, the belt abruptly vanished on October first.  Possibly due to—yeah—another interplanetary shockwave ripping it apart.

So we have just two Van Allens again.  Not since Project Runway have belts caused so much drama! 

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The Loh Down on Science is produced by LDOS Media Lab, with 89.3 KPCC. And made possible by the generous support of the Gordon and Betty Moore Foundation.

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