The more we learn about Jupiter, the more we learn how little we actually knew about the mysterious giant planet. And that includes the brilliant insane auroras that are inexplicable. Now, scientists have just stumbled upon its biggest mystery yet. Jupiter auroras are the most powerful auroras in the entire Solar System, and new measurements have revealed the cosmic light is being generated by a totally unexpected power source.
“At Jupiter, the brightest auroras are caused by some kind of turbulent acceleration process that we do not understand very well,” lead researcher Barry Mauk from John Hopkins University explains.
According to Science Alert:
The Jupiter Energetic Particle Detector Instrument (JEDI) recorded energy signatures above the gas giant’s north pole as Juno whizzed by at more than 160,000 km/hr(100,000 mph).
At that speed, the device had only seconds to make its measurements, but doing so gave us our first chance to directly observe the processes behind Jupiter’s auroral emissions – and it turns out they’re very different to the ones on Earth.
On our home planet, the most intense auroral glows are created by wells of electric potential, which accelerate electrons towards the surface along lines in Earth’s magnetic field.
When these charged particles collide with gases in Earth’s upper atmosphere, the gas molecules end up releasing photons, which produce brilliant, swirling light shows in the sky above polar regions.
The undulations are the same that people go to see in the northern regions. But electrons in the Jovian atmosphere are accelerated towards Jupiter at up to 400,000 electron volts—30 times higher than the largest auroral potentials we’ve seen on Earth.
But the mystery doesn’t end there.
“Basically the aurora is a factor of 10 brighter than it should be based on Earth-like physics,” Mauk told Wired. “After orbit seven we saw what I would consider the ‘smoking gun.’”
Hints the data revealed that as the electric potentials in the magnetic field build, they become unstable, breaking into waves that could end up propelling electrons themselves.
“That to me is very exciting because it means we’ve got a lot more work to do to figure out what is exactly going on,” astrophysicist Jonathan Nichols from the University of Leicester in the UK, told The Verge. “Jupiter isn’t going to give up its secrets as lightly, it seems.”
Source: Science Alert, Nature