What makes an ordinary ringed planet turn into a dynamic world of waves, storms, and layered chemistry? Paired images of Saturn, captured by NASA’s Hubble and James Webb Space Telescopes, provide an answer to that question, offering two different versions of a single planet. While Hubble captured Saturn in visible light, showing cloud bands, seasonal color, and bright ring structures, Webb captured Saturn in infrared light, showing atmospheric and ring structures invisible to human eyes. Together, they offered the most comprehensive view of Saturn to date.
The scientific value of these images is not merely sharper images of Saturn. Rather, they allow astronomers to “study Saturn as a layered atmosphere, not a flat disk.” NASA offered an explanation: Each telescope tells a different part of Saturn’s story, offering a richer, more layered understanding of the gas giant’s atmosphere.
These images also offered a glimpse of Saturn’s far more dynamic character than its appearance lets on. The infrared view, captured by Webb, also revealed various storms in Saturn’s southern part of the planet, a “ribbon wave” in the northern mid-latitude region, and a lingering mark left behind by a massive storm that took place between 2010 and 2012. Various edges of Saturn’s well-known north polar hexagon also appear faintly in both images. This is important because Saturn’s north pole is entering a 15-year period of winter darkness, making these images some of the last high-resolution images of Saturn’s north polar darkness until 2040.
These rings also change personality depending on the way Saturn is being viewed. They look brilliant and familiar when viewed in visible light. They glow with great intensity in infrared light because of the water and ice particles. Their structures differ slightly when viewed by the two observatories. The outer rings, which are thin, look crisp in the view by the Webb telescope. Shadows under the sunlit rings can be easily seen in the view by the Hubble telescope. Even the personality of the poles changes when viewed in infrared light. They turn gray-green at 4.3 microns. It is believed to be caused by high-altitude aerosols and auroral activity.
There is one important reason why these images come at this time. Hubble has spent many years accumulating a long baseline data set on Saturn through the Outer Planet Atmospheres Legacy program. It tracks storms, banding, and seasonal changes. Webb does not replace this data set. It extends it to the atmosphere. The images taken by the two telescopes in 2024, 14 weeks apart as Saturn approaches its equinox in 2025, show the power of the combined efforts of these two telescopes. Cassini used to change the way people viewed Saturn. From far away on our planet, the two telescopes are continuing this work by using the reflected sunlight to read the weather on the surface of the giant planet.