A satellite built by CU Boulder students helped solve a decades-old space mystery

BOULDER, Colo. – A small, shoebox-sized satellite built by students at the University of Colorado Boulder has found the answer to a space riddle that has eluded scientists for decades.

The now-solved mystery involved the origins of energetic electrons in Earth’s radiation belts, known as the Van Allen belts. It turns out those electrons likely come from cosmic rays that are created in supernova explosions.

CU Boulder researchers were able to determine the particles’ origin thanks to the student-built Colorado Student Space Weather Experiment (CSSWE), which includes a shoebox-sized particle telescope. The project was launched in 2012 and has involved more than 65 students at the university since then.

The CSSWE was able to show that the energetic electrons in the Van Allen belts are created by a process called “cosmic ray albedo neutron decay,” or CRAND, in which cosmic rays entering the earth’s atmosphere smash into atoms and produce charged particles which then get trapped by our planet’s magnetic field.

Since the discovery of the Van Allen belts in 1958, scientists have thought that CRAND was the source of high-energy protons that get trapped in Earth’s magnetic field, but until now, they haven’t been able to detect the corresponding electrons.

“We are reporting the first direct detection of these energetic electrons near the inner edge of Earth’s radiation belt,” said Professor Xinlin Li. “We have finally solved a six-decade-long mystery.”

The discovery is important because it gives scientists a better understanding of the energetic electrons, which can damage satellites orbiting Earth and could be dangerous to astronauts on space walks, Li said.

A paper on the findings is published in the Dec. 13 issue of Nature.

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