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.
By studying Juno’s measurements, Sulaiman and his team found that plasma density in Jupiter’s polar environment is so low while the…
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