'Alien auroras' on Jupiter reveal a new kind of plasma wave, scientists say

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'Alien auroras' on Jupiter reveal a new kind of plasma wave, scientists say
Sharmila Kuthunur
Space
Mon, August 25, 2025 at 2:00 PM EDT
3 min read



Data from NASA's Juno spacecraft revealed faint aurora features likely triggered by charged particles coming from the edge of Jupiter's massive magnetosphere. . | Credit: NASA/SWRI/JPL-Caltech/SwRI/V. Hue/G. R. Gladstone/B. Bonfond


The shimmering northern lights that streak across Alaska's skies have wilder cousins on Jupiter — they're bigger, stranger, and now tied to a discovery helping scientists better understand space weather.

These "alien auroras" on our solar system's largest planet have revealed a previously unknown type of plasma wave, according to a study led by researchers at the University of Minnesota Twin Cities. The finding could help scientists better understand auroras on other worlds and how magnetic fields shield planets, including Earth, from harmful radiation streaming from their stars.

Auroras occur when streams of charged particles, guided by a planet's magnetic field, crash into a planet's atmosphere. On Earth, the result is the colorful northern and southern lights, visible in green and blue ribbons across the night sky. However, Jupiter's auroras are far more powerful; they're also invisible to us without instruments that detect ultraviolet or infrared light.

The latest findings concerning Jupiter's auroras are thanks to NASA's Juno spacecraft, which has been orbiting Jupiter since 2016. Juno follows a long, looping path over the planet's poles, an orbit designed to minimize the probe's exposure to Jupiter's intense radiation belts while still allowing its instruments to capture detailed measurements. This includes the Waves instrument, which can "listen" to electromagnetic signals produced by charged particles in plasma as they interact with Jupiter's magnetic field.

"The James Webb Space Telescope has given us some infrared images of the aurora, but Juno is the first spacecraft in a polar orbit around Jupiter," Ali Sulaiman, an assistant professor of physics and astronomy at the University of Minnesota who co-led the study, said in a statement.

Plasma, often called the fourth state of matter, forms when atoms are so energized that they break apart into a soup of electrons and ions. This electrically charged material flows like a fluid but also responds strongly to magnetic fields, according to the statement. Around Jupiter, which is the most magnetized planet in the solar system, plasma behaves in ways that cannot be found on Earth.



Auroras on Jupiter captured by the James Webb Space Telescope in 2023. | Credit: NASA, ESA, CSA, Jonathan Nichols (University of Leicester), Mahdi Zamani (ESA/Webb)


By studying Juno's measurements, Sulaiman and his team found that plasma density in Jupiter's polar environment is so low while the magnetic field is so strong, meaning the waves vibrate at unusually low frequencies. This creates an entirely new wave type — one that begins like a familiar Alfvén wave but transitions into what's known as a "Langmuir mode" under Jupiter's extreme conditions, the new study reports.

"While plasma can behave like a fluid, it is also influenced by its own magnetic fields and external fields," study co-lead author Robert Lysak, who is a professor of physics and astronomy at the University of Minnesota, said in the same statement.

The team also found that Jupiter's magnetic field directs charged particles differently than Earth's does. On Earth, auroras typically form ring-shaped bands around the poles. But on Jupiter, particles are funneled directly into the polar cap, producing auroras that are more concentrated and chaotic.

Although such conditions do not exist on Earth, scientists believe they may be common on the outer planets of our solar system or even on massive exoplanets orbiting other stars. Similar plasma waves could also exist on strongly magnetized stars themselves, the study suggests.

The team plans to continue analyzing Juno's data as the spacecraft makes additional orbits around Jupiter. Each pass could uncover more clues about how plasma behaves under extreme conditions and, in turn, reveal how planets — including our own — stay protected from the constant storm of radiation from their stars.

This research is described in a paper published July 16 in the journal Physical Review Letters.

https://www.yahoo.com/news/articles/alien-auroras-jupiter-reveal-kind-180000526.html