The whole auroral region fizzing and popping with light, sometimes varying by the second.
On Christmas Day 2023, astronomers turned humanity's most powerful space telescope toward Jupiter and found that the planet's auroras were doing something physics said they could not. The James Webb Space Telescope captured light displays flickering and changing within single seconds, and when compared against simultaneous Hubble ultraviolet observations, the two datasets refused to agree — pointing toward a fundamental gap in how scientists understand the flow of energy through planetary magnetospheres. What began as a holiday observation has become an invitation to revise the models by which we read the atmospheres of worlds far beyond our own.
- Jupiter's auroras were expected to shift slowly and gracefully, but JWST watched them flicker and pop with light sometimes within a single second — a pace that existing atmospheric models simply cannot account for.
- The trihydrogen cation at the heart of the mystery survives only about two and a half minutes before being destroyed, and JWST's infrared sensitivity finally allowed scientists to measure that fragile lifetime directly.
- When Hubble's ultraviolet images were laid alongside JWST's infrared data, the brightest signals in one had almost no counterpart in the other — a mismatch that left the research team openly baffled.
- Reconciling both datasets would require vast quantities of very low-energy particles reaching Jupiter's atmosphere, a scenario long considered impossible given how the planet's magnetic field is supposed to behave.
- Published in Nature Communications in May 2025, the findings do not resolve the contradiction — they formalize it, signaling that the next generation of planetary science must contend with a phenomenon that current theory says should not exist.
On Christmas Day 2023, astronomers pointed the James Webb Space Telescope at Jupiter and witnessed auroras that defied expectation. Jupiter's polar light shows are born when the sun's charged particles are caught by the planet's vast magnetic field and funneled toward the poles, where electrons collide with hydrogen and release light that dwarfs Earth's Northern Lights. Scientists believed they understood the rhythm of these displays — a gradual brightening and fading over roughly fifteen minutes. What JWST showed instead was a system fizzing with rapid, unpredictable change, sometimes shifting within a single second. "What a Christmas present it was," said Jonathan Nichols of the University of Leicester. "It just blew me away."
The team trained their attention on the trihydrogen cation, or H₃⁺ — a molecule born when energetic electrons strike hydrogen, glowing in infrared and carrying heat away from the planet. It is a delicate molecule, easily destroyed, and JWST's infrared cameras were sensitive enough to measure its lifetime directly for the first time: roughly two and a half minutes. That measurement alone advanced what ground-based telescopes had never been able to pin down.
But the deeper mystery emerged when the team compared JWST's infrared data with simultaneous ultraviolet observations from the Hubble Space Telescope. The two records did not align. The brightest infrared signals JWST detected had almost no counterpart in Hubble's images. To explain both datasets together, the auroras would need to be bombarded by enormous quantities of very low-energy particles — a scenario long considered physically impossible, because Jupiter's magnetic field should block such particles from reaching the atmosphere in those concentrations.
The findings, published in Nature Communications in May 2025, do not offer a resolution. They formalize a contradiction, suggesting that something about how particles move through Jupiter's magnetosphere remains fundamentally misunderstood — and that the models used to explain how planetary atmospheres heat and cool may need to be rebuilt around a phenomenon that, by current theory, should not exist.
On Christmas Day 2023, astronomers pointed the James Webb Space Telescope at Jupiter and watched something that shouldn't have been there. What they saw in the planet's auroras—those shimmering light shows that dance across its poles—didn't match what physics said should happen. The discovery has left researchers puzzled about how Jupiter's atmosphere actually works.
Jupiter's auroras are born from violence. The sun hurls charged particles across the solar system, and Jupiter's enormous magnetic field catches them like a net, funneling them toward the poles. There, electrons slam into hydrogen atoms, and the collision releases light so brilliant it outshines Earth's Northern Lights by hundreds of times. Scientists have studied these displays for decades, but they thought they understood the basic rhythm: auroras would brighten and fade gradually, perhaps over fifteen minutes or so. When Jonathan Nichols and his team at the University of Leicester decided to watch with JWST's infrared cameras, they expected a slow, stately dance.
Instead, the auroras were fizzing. The entire region flickered and popped with light, changing sometimes within a single second. "What a Christmas present it was," Nichols said. "It just blew me away." The team had wanted to measure how quickly the auroras shifted, and the answer turned out to be far faster than anyone had predicted. This rapid variability suggested something more complex was happening in Jupiter's upper atmosphere than current models could explain.
The researchers focused on a specific molecule called the trihydrogen cation, or H₃⁺. When energetic electrons collide with hydrogen in Jupiter's atmosphere, they create this molecule, which glows in infrared light. That glow carries heat away from the planet—a crucial part of how Jupiter's atmosphere stays in thermal balance. But H₃⁺ is fragile. Fast-moving electrons can destroy it almost as quickly as it forms. Using JWST's infrared camera, the team measured how long H₃⁺ actually survives: about two and a half minutes before being torn apart. That measurement alone was valuable, because ground-based telescopes have never been sensitive enough to pin down the molecule's lifetime.
But then came the real puzzle. The researchers had also aimed the Hubble Space Telescope at Jupiter at the same time, capturing ultraviolet light from the auroras. When they compared the two datasets, something didn't add up. The brightest infrared light JWST detected had almost no match in Hubble's ultraviolet images. "Bizarrely, the brightest light observed by Webb had no real counterpart in Hubble's pictures," Nichols said. "This has left us scratching our heads."
To produce the combination of brightness patterns they observed—the infrared glow JWST saw and the ultraviolet light Hubble captured—the auroras would need to be struck by enormous quantities of very low-energy particles. The problem is that scientists have long believed such a collision pattern should be impossible. Jupiter's magnetic field should prevent low-energy particles from reaching the atmosphere in those concentrations. Yet the telescopes showed it happening anyway. The findings, published in Nature Communications in May 2025, suggest that something about how particles flow through Jupiter's magnetosphere remains fundamentally misunderstood. The mystery points toward a gap in the models astronomers use to explain how planetary atmospheres heat and cool, and it means the next generation of observations will need to grapple with a phenomenon that shouldn't exist.
Notable Quotes
We wanted to see how quickly the auroras change, expecting them to fade in and out ponderously, perhaps over a quarter of an hour or so. Instead, we observed the whole auroral region fizzing and popping with light, sometimes varying by the second.— Jonathan Nichols, University of Leicester
In order to cause the combination of brightness seen by both Webb and Hubble, we need to have a combination of high quantities of very low-energy particles hitting the atmosphere, which was previously thought to be impossible.— Jonathan Nichols
The Hearth Conversation Another angle on the story
Why does it matter that the auroras change by the second instead of over minutes?
Because it tells us the atmosphere is responding to something we can't fully account for. If auroras were just a slow, steady process, we'd understand it. The flickering means there's rapid energy transfer happening—something driving those changes that our current models don't capture.
And the H₃⁺ molecule—why focus on that specifically?
It's the messenger. When it forms and glows, it's releasing heat. When it gets destroyed, that tells us something about the particle environment around it. By measuring how long it lasts, we get a window into the actual conditions in Jupiter's upper atmosphere.
So what's the real puzzle here—the speed, or the brightness mismatch?
Both, but the brightness mismatch is the one that breaks the model. We can explain rapid changes if we invoke more complex dynamics. But the infrared brightness without corresponding ultraviolet light suggests low-energy particles are there in quantities that shouldn't be possible given what we know about Jupiter's magnetic field.
Could the telescopes be wrong?
Unlikely. JWST and Hubble are among the most reliable instruments we have. The issue is that reality is more complicated than the theory predicted. That's actually exciting—it means there's something fundamental about magnetospheres we're still missing.
What happens next?
More observations, better models. The next step is figuring out what mechanism could deliver those low-energy particles to the atmosphere. That might reshape how we understand not just Jupiter, but how magnetic fields work on other planets too.