NASA space telescope spots most powerful light ever seen on Jupiter, helps solve 30-year-old mystery

Jupiter's southern hemisphere, as seen by NASA's Juno spacecraft. In a new study, NASA's NuSTAR space telescope spots the highest-energy light from Jupiter. (Image credit: Enhanced image by Kevin M. Gill (CC-BY) based on images provided courtesy of NASA/JPL-Caltech/SwRI/MSSS)

NASA has detected the most energetic light ever seen on Jupiter and, in the process, solved a 30-year-old mystery.

In a new study, researchers using NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) space observatory were able to spot the highest-energy light ever seen on Jupiter. The light, which is X-ray radiation, is also the highest-energy light ever seen on a planet in our solar system other than Earth. 

But this finding isn't just an incredible observation; it's also helping scientists to understand why NASA's Ulysses sun-studying mission mysteriously saw no X-rays from Jupiter when it flew by the planet in 1992.

In photos: Juno's amazing views of Jupiter

NuSTAR detected high-energy X-rays from the auroras near Jupiter’s north and south poles. NuSTAR cannot locate the source of the light with high precision, but can only find that the light is coming from somewhere in the purple-colored regions.  (Image credit: NASA/JPL-Caltech)

This is not the first time that X-rays have been spotted at Jupiter; NASA's Chandra X-ray Observatory as well as the European Space Agency's XMM-Newton observatory have both observed low-energy X-rays coming from auroras on the giant planet. 

Jupiter's auroras, which occur at the planet's north and south poles, are created by ions coming from the planet's volcanic moon Io that are accelerated by the planet's magnetic field toward the poles. There, the ions interact with Jupiter's atmosphere and release light, creating aurora light shows. NASA's Juno spacecraft, which arrived at Jupiter in 2016, found that electrons from Io also interact with the planet's magnetic field.

Scientists have suspected that these electrons from Io could create even more powerful X-rays than the planet's auroras. With the NuSTAR observations, researchers have confirmed for the first time that Io's electrons are indeed creating high-energy X-rays.

NuSTAR, which launched to space in 2012, is a space-based X-ray telescope that studies the cosmos in high-energy X-rays. 

"It's quite challenging for planets to generate X-rays in the range that NuSTAR detects," Kaya Mori, an astrophysicist at Columbia University and lead author of the new study, said in a statement. "But Jupiter has an enormous magnetic field, and it's spinning very quickly. Those two characteristics mean that the planet's magnetosphere acts like a giant particle accelerator, and that's what makes these higher-energy emissions possible."

By spotting these high-energy X-rays, the researchers in this study may also have solved an ongoing mystery. In 1992, the TK agency's Ulysses spacecraft, launched in 19TK to do TKTK, flew by Jupiter but didn't detect any X-rays of any kind — which has puzzled scientists since. 

According to the researchers behind the new study, Ulysses likely didn't spot any X-rays because, due to the mechanism that brings this light about, the X-rays become fainter at higher energies. And so, in Ulysses' detection range, they suspect Jupiter's X-rays were simply too faint to see.

This work was described in a new study published Thursday (Feb. 10) in the journal Nature Astronomy.

Email Chelsea Gohd at or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at:

Chelsea Gohd
Senior Writer

Chelsea “Foxanne” Gohd joined in 2018 and is now a Senior Writer, writing about everything from climate change to planetary science and human spaceflight in both articles and on-camera in videos. With a degree in Public Health and biological sciences, Chelsea has written and worked for institutions including the American Museum of Natural History, Scientific American, Discover Magazine Blog, Astronomy Magazine and Live Science. When not writing, editing or filming something space-y, Chelsea "Foxanne" Gohd is writing music and performing as Foxanne, even launching a song to space in 2021 with Inspiration4. You can follow her on Twitter @chelsea_gohd and @foxannemusic.