Scientists have discovered that the colorful light shows seen above Earth’s poles also occur on Ganymede, Jupiter’s largest moon—and they behave in strikingly similar ways.
New observations reveal that despite vast differences between the two worlds, the basic processes that create auroras may be shared across the solar system.
Auroras on Earth, often called the northern and southern lights, appear when charged particles from the sun slam into our planet’s magnetic field.
This interaction sends energy into the upper atmosphere near the poles, where it excites oxygen and nitrogen atoms and makes them glow in shades of green, red, purple, and blue.
Although auroras are usually seen at high latitudes, recent solar activity has made them visible farther from the poles.
Ganymede, unlike any other moon, has its own magnetic field, making it more similar to a planet than a typical satellite. It also has a very thin atmosphere made mostly of oxygen.
When energetic particles from Jupiter’s powerful magnetic environment strike this atmosphere, they produce auroras as well.
An international team of researchers led by scientists from the University of Liège used data from NASA’s Juno spacecraft to study Ganymede’s auroras in unprecedented detail.
Juno flew past the moon in July 2021, giving scientists a rare close-up view that lasted less than 15 minutes. During that time, its ultraviolet instruments captured images sharp enough to reveal fine structures that had never been seen before.
Instead of appearing as smooth glowing bands, Ganymede’s auroras were broken into chains of bright patches. Scientists call these structures “beads.”
Similar bead-like patterns have been observed in Earth’s auroras and in those of Jupiter, where they are linked to powerful disturbances in the magnetic environment that release large amounts of energy. These events can intensify auroras and cause them to flicker and shift rapidly.
The discovery suggests that the same fundamental physics may be at work on different worlds. Ganymede interacts with Jupiter’s magnetic field much like Earth interacts with the solar wind from the sun.
This means that whenever a magnetic field, an atmosphere, and charged particles come together, auroras with similar features can form—even on a moon.
Studying auroras is important because they provide clues about space weather and how energetic particles move through planetary environments. Understanding these processes can help scientists learn more about the conditions around other planets and moons, and how they evolve over time.
Because Juno’s flyby was brief, researchers still do not know how common these bead-like auroras are on Ganymede or how they change. A future mission may provide answers. The European Space Agency’s Jupiter Icy Moons Explorer, known as JUICE, is on its way to the Jovian system and is expected to arrive in 2031. It will carry instruments designed to observe Ganymede for extended periods, offering a much deeper look at its mysterious light shows.
These findings highlight an unexpected connection between Earth and a distant moon, showing that even across billions of kilometers, the universe can produce familiar wonders in remarkably similar ways.
Source: KSR.
