MessageToEagle.com - A previously unknown third radiation belt around Earth,
revealing the existence of unexpected structures and processes within these hazardous regions of space has been discovered by
NASA's Van Allen Probes mission.
Based on observations of Earth's Van Allen belts, scientists have long known and documented two distinct regions of trapped radiation
surrounding our planet.
Particle detection instruments aboard the
twin Van Allen Probes, launched Aug. 30, quickly revealed to scientists the existence of this new, transient,
third radiation belt.
Click on image to enlarge
A graphic depicting the twin Van Allen Probes in orbit within Earth's magnetic field. Credit: JHU/APL
The belts, named for their discoverer, James Van Allen, are critical regions for modern society, which is dependent
on many space-based technologies. The Van Allen belts are affected by solar storms and space weather and can swell
dramatically. When this occurs, they can pose dangers to communications and GPS satellites, as well as humans in space.
"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 in Washington.
This discovery shows the dynamic and variable nature of the radiation belts and improves our understanding of how
they respond to solar activity.
The new high-resolution observations revealed there can be three distinct, long-lasting belt structures with the
emergence of a second empty slot region, or 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 (LASP) at the University of Colorado in Boulder.
Click on image to enlarge
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. Credit: NASA/Van Allen
Probes/Goddard Space Flight Center
"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."
Each Van Allen Probe carries an identical set of five instrument suites that allow scientists to gather data on the
belts in unprecedented detail. The data are important for the study of the effect of space weather on Earth, as well
as fundamental physical processes observed around other objects, such as planets in our solar system and distant nebulae.
"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 in Laurel, Md.
"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."
Observations were made by scientists from institutions including LASP; NASA's Goddard Space Flight Center in Greenbelt,
Md.; Los Alamos National Laboratory in Los Alamos, N.M.; and the Institute for the Study of Earth, Oceans, and Space at
the University of New Hampshire in Durham.
The findings, published February 28 in the journal
Science, are the result of data gathered by the first dual-spacecraft mission to fly through our planet's radiation belts.