This image was created using data from the
Relativistic Electron-Proton Telescopes on NASA's twin Van Allen Probes. It
shows the emergence of a new third transient radiation belt. The new belt is
seen as the middle orange and red arc of the three seen on each side of the
Earth.
Image Credit:
APL, NASA
NASA's twin Van Allen Probes will celebrate on Saturday two years of studying
the sun’s influence on our planet and near-Earth space. The probes, shortly
after launch in August 2012, discovered a third radiation belt around Earth when
only two had previously been detected.
The radiation belts are layers of energetic charged particles held in place
by the magnetic field surrounding our planet. The new third belt occurred only
occasionally but persisted for as long as a month. This revealed to scientists
the dynamic and variable nature of the radiation belts and provided new insight
into how they respond to solar activity.
"The primary science objective of the Van Allen Probes is to provide
understanding of how particles in the radiation belts form and change in
response to energy input from the sun," said Mona Kessel, the mission’s program
scientist at NASA Headquarters in Washington. "The discoveries and
understanding gained have far exceeded expectations."
The probes, each weighing just less than 1,500 pounds, were specifically
designed to withstand and study the harsh radiation belt region around Earth.
The belts are critical regions that have a connection to Earth’s atmosphere and
space-based technologies. The belts are affected by solar storms and space
weather events and as a result, can swell dramatically. When this occurs, they
can pose dangers to communications and GPS satellites, as well as humans in
low-Earth orbit.
Formerly known as the Radiation Belt Storm Probes, the mission was renamed
Van Allen Probes in November 2012 in honor of Dr. James Van Allen, who
discovered the two radiation belts in 1958.
The twin spacecraft have also revealed how particles in the heart of the belts can be accelerated to nearly the speed of light; proven that electrons in the belts are undergoing acceleration from very low frequency plasma waves; and shown persistent stripe-like structures are a common feature of the inner belt, and are caused by Earth’s rotation, a mechanism previously thought to be incapable of such an effect.
The twin spacecraft have also revealed how particles in the heart of the belts can be accelerated to nearly the speed of light; proven that electrons in the belts are undergoing acceleration from very low frequency plasma waves; and shown persistent stripe-like structures are a common feature of the inner belt, and are caused by Earth’s rotation, a mechanism previously thought to be incapable of such an effect.
“The Van Allen Probes mission has given us the means to validate theories
about plasma physics and the acceleration processes going on inside the belts,”
said Barry Mauk, Van Allen Probes project scientist at the Johns Hopkins
University Applied Physics Laboratory (APL) in Laurel, Maryland. “They also have
shown us new structures and features in this region of space, the existence of
which we had never suspected. It has been a very illuminating two years, and we
look forward to many more with these remarkable spacecraft.”
The Van Allen Probes are the second mission in NASA's Living With a Star
(LWS) Program to explore aspects of the connected sun-Earth system that directly
affect life and society. LWS is managed by the agency's Goddard Space Flight
Center in Greenbelt, Maryland. APL built the spacecraft and manages the mission
for the agency’s Science Mission Directorate in Washington.
For more information about NASA’s Van Allen Probes, visit
NASA
Guillermo Gonzalo Sánchez Achutegui
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