Jupiter’s Northern Lights are underway for a more dynamic and confusing light show than scientists have expected. New observations from the James Webb Space Telescope (JWST) suggest that the petrol giant’s aurora can flash and change in seconds, challenging previous understanding of how these huge light performances behave.
The discovery, published in Nature Communications on May 12, compares simultaneous infrared and ultraviolet observations of Jupiter’s aurora, thus providing unprecedented insights into the Earth’s upper atmosphere and magnetic fields.
“That’s what Christmas gift – it blows me away!” said Jonathan Nichols of the University of Leicester, who leads the research team. “We wanted to see how fast the aurora changes, hoping it will fade away, maybe more than a quarter of an hour or so. Instead, we observed the entire aurora area with hoarseness and popping light, sometimes in the second change.”
Tracking flashing lights
The researchers used Weber’s near-infrared camera to capture images of Jupiter’s northern aurora emissions and captured an unprecedented 3-second time resolution on December 25, 2023 – 100 times faster than typical ground-based observations.
The research focuses on the emission of trihydrogen ions (H3+), which plays a key role in Jupiter’s atmospheric energy balance. These ions form when energy particles accelerate in Jupiter’s magnetosphere.
The team estimates that H3+ has only 150 seconds of short lifespan in Jupiter’s Aurora – far less than the previous estimate of 10-15 minutes. This shorter lifetime means Aurora responds much faster to changes in Jupiter’s magnetosphere than previously thought.
Confusing brightness mode
These observations reveal several unexpected features, including the bright “Dunny Activity Area” (DAR), which glows strongly in infrared light but has few counterparts in UV observations.
“It’s strange that the brightest light that Webber observed has no real opponent in Hubble’s pictures,” Nichols noted. “This made us grab the head. To cause a combination of brightness that both Webber and Hubble saw, we needed to hit the atmosphere with obviously impossible large quantities of very low energy particles – like a drizzle brutality! We still don’t understand how this happened.”
Simultaneous observations of Webb and Hubble show that while some aurora features appear at both wavelengths, other functions are unique to infrared or ultraviolet light.
A fast moving pulse
The team also discovered the Aurora Pulse (REAPS) that traveled quickly eastward – the light waves moved at a speed of 60 km per second, about 20 times the rotation rate of Jupiter. The period of these pulses is about 1.6 minutes, possibly connected to electromagnetic waves in Jupiter’s magnetosphere.
Similar rapid pulsation was observed, traveling along the “tail” of the aurora connected to Jupiter’s moon IO, traveling at a speed of about 67 km per second.
Effects on planetary heating
These findings are of great significance to understanding how Jupiter’s upper atmosphere heats up, a long-term problem in planetary science.
The researchers found that H3+ radiates only 2% of the thermal energy deposited by electron precipitation during the aurora flare, which makes Jupiter’s upper atmosphere lower than previously believed “thermotors”.
In some areas, such as the active areas at dusk, H3+ radiation exceeds the local heating rate, while in others it is reduced – suggesting a complex energy balance mechanism in the work of Jupiter’s polar regions.
Future research
These observations open new avenues to understand Jupiter’s complex space environment and may provide context for the European Space Agency’s Jupiter Ice Sanitation Explorer (JUICE) mission, which is currently on its way to the giant planet.
The team plans to make other Webb observations and compare them to data from NASA’s Juno Spacecraft, which has been orbiting Jupiter since 2016 to better understand the reasons for these mysterious aurora functions.
By mapping the detailed behavior of Jupiter’s Aurora, scientists hope to gain insight into the Earth’s magnetic field, the interaction between the atmosphere and satellites – knowledge can improve our understanding of the magnetic field and atmosphere in the universe.
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