NASA this week revealed that its Van Allen Probes have discovered a third radiation belt around the Earth. Before now, the Earth's Van Allen belts were thought to be two belts of radiation surrounding the planet.
The newly discovered belt of radiation was observed for four weeks before a shockwave from the sun blew it apart. The new belt could improve researchers' understanding of how the belts react to space weather, and in particular solar winds. The research was published this week in the journal Science.
"Even 55 years after their discovery, the Earth's radiation belts still are capable of surprising us and still have mysteries to discover and explain," said Nicky Fox, Van Allen Probes deputy project scientist at the Johns Hopkins University Applied Physics Laboratory. "We thought we knew the radiation belts, but we don't. The advances in technology and detection made by NASA in this mission already have had an almost immediate impact on basic science."
The new belt was detected by the Relativistic Electron Proton Telescope (REPT) on-board the Van Allen Probes. The probes discovered that a region thought to be one belt had actually become two distinct belts with space in between.
"This is the first time we have had such high-resolution instruments look at time, space and energy together in the outer belt," said Daniel Baker, lead author of the study and REPT instrument lead at the Laboratory for Atmospheric and Space Physics at the University of Colorado. "Previous observations of the outer radiation belt only resolved it as a single blurry element. When we turned REPT on just two days after launch, a powerful electron acceleration event was already in progress, and we clearly saw the new belt and new slot between it and the outer belt."
The Van Allen Probes were launched back in August with the mission of studying the Van Allen belts and how space weather can affect them. By December of last year data from the probes was already revealing to scientists just how much influence the sun has over the Earth's magnetosphere.
"The fantastic new capabilities and advances in technology in the Van Allen Probes have allowed scientists to see in unprecedented detail how the radiation belts are populated with charged particles and will provide insight on what causes them to change, and how these processes affect the upper reaches of Earth's atmosphere," said John Grunsfeld, NASA's associate administrator for science.