06/13/2026
⚡ Jupiter has been caught doing something usually associated with the most violent places in the Universe.
Using NASA’s Juno spacecraft, scientists have directly observed electrons near Jupiter being accelerated to relativistic energies, meaning they were pushed to nearly the speed of light.
The action happens at Jupiter’s bow shock, the huge boundary where the solar wind slams into the planet’s enormous magnetic field. Just upstream of that boundary is a turbulent foreshock region, where magnetic structures can trap and energize particles.
Juno crossed this region on October 1, 2023. Its instruments detected electrons reaching at least 1 MeV, far higher than the nearby bow shock crossing itself. The real accelerator seems to be a giant foreshock transient, a moving plasma structure spanning several Jupiter radii.
That is important because collisionless shocks are found everywhere in space, from planets to supernova remnants. They are also one of the main suspects behind cosmic rays, the high energy particles constantly raining through the galaxy.
The study suggests there may be a scaling rule: bigger shock systems can build bigger acceleration regions, and those regions can push particles to higher energies.
Jupiter is not just a planet here. It is a nearby laboratory for cosmic particle acceleration.
📄 RESEARCH PAPER
📌 Raptis et al., “Relativistic electron acceleration at the bow shock of Jupiter and beyond”, Nature (2026)
