Hey, hey, it’s everyone’s favorite 7th planet from the Sun! Webb has provided us with the first vertical view of Uranus’s ionosphere, revealing auroras shaped by its tilted magnetic field. Getting a look at the structure of the region where the atmosphere interacts strongly with the planet’s magnetic field is giving us the most detailed portrait yet of where its auroras form, how the magnetic field influences them, and also data on how Uranus’s atmosphere has continued to cool since the 1990s. Uranus has the strangest magnetosphere in the Solar System. It is tilted and offset from the planet’s rotation axis (and this planet already rolls around the Sun nearly on its side), which means auroras move across the surface in complex ways. Better understanding Uranus will give us insight into ice-giant planets and help us better characterize giant planets outside our Solar System. This image collage shows 5 time-stamped images mapping the vertical structure of Uranus's atmosphere, uncovering how temperature and charged particles vary with height across the planet. Using Webb’s NIRSpec instrument, the team detected the faint glow from molecules high above the clouds. These unique data provide the most detailed portrait yet of where the planet’s auroras form, how they are influenced by its unusually tilted magnetic field, and how Uranus’s atmosphere has continued to cool over the past three decades. The results offer a new window into how ice-giant planets distribute energy in their upper layers. Two bright auroral bands were detected near Uranus’s magnetic poles, together with reduced emission and ion density in part of the region between the two bands (a feature likely linked to transitions in magnetic field lines). Image Credit: ESA/Webb, NASA, CSA, STScI, P. Tiranti, H. Melin, M. Zamani (ESA/Webb) Read more: esawebb.org/news/weic2602/ Image description: Collage of time-stamped images of Uranus's upper atmosphere, showing auroras. Four images are in a square on the left and one large image is on the right. In each of the four images on the left, the time is located in the bottom left corner of each: top left: 09:10 UTC, top right: 12:45 UTC, bottom left: 16:30 UTC, bottom right: 20:15 UTC." In the large image on the right, the words "Uranus 19-20 Jan 2025" are in the upper left corner, "0:37 UTC" and "Webb/NIRSpec" in the bottom left, and a key of altitude ranging from 500km to 5000km, blue to red, is in the bottom right. Each image shows the planet Uranus set against the blackness of space. The planet appears as a smooth, bright cyan disc at the center, its atmosphere reveals soft, hazy tones of blue. Surrounding the planet is a vivid reddish glow, forming a diffuse halo that contrasts strongly with the cool blue of the planetary disc. Encircling Uranus are several thin, concentric rings, visible as pale gray arcs. Subtle variations in brightness can be seen across the planet’s face, with slightly brighter patches near the limb, hinting at atmospheric structure.

Hey, hey, it’s everyone’s favorite 7th planet from the Sun! Webb has provided us with the first vertical view of Uranus’s ionosphere, revealing auroras shaped by its tilted magnetic field. Getting a look at the structure of the region where the atmosphere interacts strongly with the planet’s magnetic field is giving us the most detailed portrait yet of where its auroras form, how the magnetic field influences them, and also data on how Uranus’s atmosphere has continued to cool since the 1990s. Uranus has the strangest magnetosphere in the Solar System. It is tilted and offset from the planet’s rotation axis (and this planet already rolls around the Sun nearly on its side), which means auroras move across the surface in complex ways. Better understanding Uranus will give us insight into ice-giant planets and help us better characterize giant planets outside our Solar System. This image collage shows 5 time-stamped images mapping the vertical structure of Uranus's atmosphere, uncovering how temperature and charged particles vary with height across the planet. Using Webb’s NIRSpec instrument, the team detected the faint glow from molecules high above the clouds. These unique data provide the most detailed portrait yet of where the planet’s auroras form, how they are influenced by its unusually tilted magnetic field, and how Uranus’s atmosphere has continued to cool over the past three decades. The results offer a new window into how ice-giant planets distribute energy in their upper layers. Two bright auroral bands were detected near Uranus’s magnetic poles, together with reduced emission and ion density in part of the region between the two bands (a feature likely linked to transitions in magnetic field lines). Image Credit: ESA/Webb, NASA, CSA, STScI, P. Tiranti, H. Melin, M. Zamani (ESA/Webb) Read more: esawebb.org/news/weic2602/ Image description: Collage of time-stamped images of Uranus's upper atmosphere, showing auroras. Four images are in a square on the left and one large image is on the right. In each of the four images on the left, the time is located in the bottom left corner of each: top left: 09:10 UTC, top right: 12:45 UTC, bottom left: 16:30 UTC, bottom right: 20:15 UTC." In the large image on the right, the words "Uranus 19-20 Jan 2025" are in the upper left corner, "0:37 UTC" and "Webb/NIRSpec" in the bottom left, and a key of altitude ranging from 500km to 5000km, blue to red, is in the bottom right. Each image shows the planet Uranus set against the blackness of space. The planet appears as a smooth, bright cyan disc at the center, its atmosphere reveals soft, hazy tones of blue. Surrounding the planet is a vivid reddish glow, forming a diffuse halo that contrasts strongly with the cool blue of the planetary disc. Encircling Uranus are several thin, concentric rings, visible as pale gray arcs. Subtle variations in brightness can be seen across the planet’s face, with slightly brighter patches near the limb, hinting at atmospheric structure.