Wednesday, August 07, 2013

Podcast: Acceleration Secrets of the Van Allen Radiation Belts

Looking up at the night sky, our eyes can see stars and planets and other distant objects. This transparency sometimes gives the impression that Earth is surrounded by emptiness. In reality, the area around our planet is teeming with activity.
This week on the podcast I talk with astrophysicist Geoff Reeves about some of the activities going on just above our heads; specifically, the acceleration of particles in a region known as the Van Allen radiation belts.  Extending from as low as 60 miles, to as high as 60,000 miles above the surface of the Earth, the Van Allen belts are regions of high-energy, fast moving particles, that follow the lines of the Earth's magnetic fields (so they look like a donut-shaped shell around the earth).

NASA/Van Allen Probes/Goddard Space Flight Center
The belts have caused problems for humans in the last few decades, as they can occasionally damage satellites, particularly during solar storms (when the sun sends even more high energy particles careening toward us).

Scientists have been interested in understanding how the particles in the Van Allen belts are accelerated, in hopes of one day being able to predict when and where the belts will be most harmful to satellites. In 2012 NASA launched the Van Allen Space Probes to study these peculiar regions. In the July issue of the journal Science, Reeves and a group of colleagues published an analysis of some of the earliest data sent back by the Probes. The results confirm the presence of a previously unobserved mechanism for accelerating the particles.

Listen to the podcast to find out what Reeves and colleagues uncovered, and what it tells us about the universe.

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