The radiating “donut shape” around Earth has a surprising structure discovered this week. The scientists who made the discovery have dubbed it “zebra stripes.”
Wired has the story:
The Van Allen belts, which extend high above our planet’s atmosphere, are made of high-energy protons and electrons emanating from the sun that have become trapped in the Earth’s magnetic field. The belts were discovered in the 1950s, but in 2012 NASA launched twin satellites called the Van Allen probes to study them in detail. In the course of their work, the satellites noticed a population of highly energetic electrons that are slanted relative to the rest of the belts. Because of their tilt, researchers thought they look like zebra stripes. The colorful graphic above shows the newly discovered structure’s banded pattern, making them look a bit more like those terrible Fruit Stripe chewing gum packs you bought as a kid when all the good flavors were sold out.
Most activity in the Van Allen belts is governed by the sun. When our local star is near the peak of its solar cycle and producing large amounts of activity, radiation levels in the belts can significantly increase (which sometimes becomes problematic for astronauts). When scientists first saw the zebra stripe pattern, they assumed it was in some way connected to the sun’s activity. Surprisingly, it’s not the sun but the Earth that is responsible for the Van Allen zebra stripes.
To read more, head over to Wired.