- Juno mission detected particles near Jupiter moving close to the speed of light
- The discovery helps explain the origin of high-energy particles like cosmic rays
- Jupiter's larger bow shock accelerates electrons to higher speeds than near Earth
NASA's Juno mission has captured particles travelling close to the speed of light near Jupiter, providing new evidence about how and where high-energy particles, including cosmic rays, are formed, reported NASA.
Astronomers have been trying to understand the origins of cosmic rays since their discovery more than 100 years ago. These energetic particles can come from a variety of sources, including supernovas and eruptions from the Sun.
When solar cosmic rays, also known as solar energetic particles, reach Earth, they can cause space weather effects that disrupt satellites, communications systems and power networks.
Previous NASA missions, including MMS (Magnetospheric Multiscale) and THEMIS (Time History of Events and Macroscale Interactions during Substorms), showed how some electrons become highly energised in a region near Earth known as the foreshock. This is the area where solar particles first encounter Earth's magnetic field.
Scientists believed that the same process was responsible for accelerating high-energy particles in foreshocks around other planets and astrophysical systems. However, they had not been able to directly confirm this theory.
New observations from Jupiter have now provided direct confirmation of the process.
While orbiting the gas giant, Juno measured high-speed electrons in Jupiter's foreshock region. The spacecraft found that these electrons reached even higher speeds than those observed near Earth.
Researchers said the increase in speed was linked to Jupiter's much larger bow shock, which forms when the planet's magnetic field pushes through the stream of solar particles.
The results of the study were published on Wednesday in the journal Nature.
Scientists also found that the scaling relationship observed near Jupiter matched cosmic rays arriving from supernovas across the galaxy. In these much larger magnetic environments, particles can be accelerated to even greater speeds.
The findings suggest that the same process observed within the solar system may also operate throughout the universe, helping produce some of the highest-energy particles known to science.
