The term Van Allen belts refers specifically to the radiation belts surrounding Earth; however, similar radiation belts have been discovered around other planets. A radiation belt is a layer of energetic charged particles that is held in place around a magnetized planet, such as the Earth, by the planet’s magnetic field. The Earth has two such belts and sometimes others may be temporarily created. The discovery of the belts is credited to James Van Allen (1958) and as a result the Earth’s belts bear his name. The main belts extend from an altitude of about 1,000 to 60,000 kilometers above the surface in which regionradiation levels vary. Most of the particles that form the belts are thought to come from solar wind and other particles by cosmic rays.
The radiation belts look like two giant donuts. Earth sits at the center of the “donut hole.” During periods of intense space weather, the density and energy of radiation belt particles can increase and pose a danger to astronauts, spacecraft, and even technologies on the ground. Some particles in the radiation belts move at nearly the speed of light, which is about 186,000 miles per second. Our society relies on more than 800 satellites operating in the radiation belts for communication and navigation.
In the 60’s and 70’s when the Apollo mission that put man on the moon were on, there was huge discussions surrounding the safety of astronauts when passing through these belts.
In 2013, NASA reported that the Van Allen Probes had discovered a transient, third radiation belt, which was observed for four weeks until destroyed by a powerful, interplanetary shock wave from the Sun.
The Van Allen Probes (formerly known as the Radiation Belt Storm Probes) are two robotic spacecraft being used to study the Van Allen radiation belts that surround Earth. NASA is conducting the Van Allen Probes mission as part of the Living With a Star program. Understanding the radiation belt environment and its variability has important practical applications in the areas of spacecraft operations, spacecraft system design, mission planning and astronaut safety. The probes were launched on August 30, 2012.
Jupiter has a powerful magnetic field 20,000 times stronger than the Earth’s. It is therefore of no surprise that the highly energetic and damaging particles flying around in the Earths Van Allen Belts can be found within Jupiter’s magnetosphere too.New research suggests that the magnetospheres of Jupiter and Earth may have more in common than previously thought.
References: wikipedia, nasa.gov