Mar 25

NASA Webb, Hubble Share Most Comprehensive Telescopic View of Saturn to Date

Side-by-side comparison of Saturn observed at different wavelengths and times show how differently it appears in infrared, on the left, versus visible light, on the right. Left image is labeled Saturn, Webb Infrared Light, November 29, 2024. Right image is labeled Saturn, Hubble Visible Light, August 22, 2024. In infrared, Saturn has horizontal bands, with bands at the north and south poles appearing darker orange and lightening to tan as they approach the equator. The north and south poles glow a greenish-grey. The rings appear in an icy neon white. White dots, representing several of Saturn’s moons, are labeled Janus, Dione, and Enceladus. In visible, Saturn’s horizontal bands appear pale yellow, with some bands towards the north and south pole having a light blue hue. The rings appear bright white, glowing slightly less than Webb’s infrared image. White dots, representing several of Saturn’s moons, are labeled Janus, Mimas, and Epimetheus.
Side-by-side views of Saturn from NASA’s James Webb Space Telescope (left) and Hubble Space Telescope (right) reveal the planet in infrared and visible light. Hubble highlights subtle cloud banding and color variations, while Webb’s infrared vision probes different atmospheric layers, bringing out storms, waves, and glowing ring structures in striking detail. Credits: Image: NASA, ESA, CSA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

NASA’s James Webb Space Telescope and Hubble Space Telescope have teamed up to capture new views of Saturn, revealing the planet in strikingly different ways. Observing in complementary wavelengths of light, the two space observatories provide scientists with a richer, more layered understanding of the gas giant’s atmosphere.

Both sense sunlight reflected from Saturn’s banded clouds and hazes, but where Hubble reveals subtle color variations across the planet, Webb’s infrared view senses clouds and chemicals at many different depths in the atmosphere, from the deep clouds to the tenuous upper atmosphere.

Together, scientists can effectively ‘slice’ through Saturn’s atmosphere at multiple altitudes, like peeling back the layers of an onion. Each telescope tells a different part of Saturn’s story, and the observations together help researchers understand how Saturn’s atmosphere works as a connected three-dimensional system. Both complement previous observations done by NASA’s Cassini orbiter during its time studying the Saturnian system from 1997 to 2017.

The Hubble image seen here was captured as part of a more than a decade long monitoring program called OPAL (Outer Planet Atmospheres Legacy) in August 2024, while the Webb image was captured a few months later using Director’s Discretionary Time

The newly released images highlight features from Saturn’s busy atmosphere.

In the Webb image, a long-lived jet stream known as the “ribbon wave” meanders across the northern mid-latitudes, influenced by otherwise undetectable atmospheric waves. Just below that, a small spot represents a lingering remnant from the “Great Springtime Storm” of 2010 to 2012.  Several other storms dotting the southern hemisphere of Saturn are visible in Webb’s image, as well. 

All these features are shaped by powerful winds and waves beneath the visible cloud deck, making Saturn a natural laboratory for studying fluid dynamics under extreme conditions.

Several of the pointed edges of Saturn’s iconic hexagon-shaped jet stream at its north pole, discovered by NASA’s Voyager spacecraft in 1981, are also faintly visible in both images. It remains one of the solar system’s most intriguing weather patterns. Its persistence over decades highlights the stability of certain large-scale atmospheric processes on giant planets. These are likely the last high-resolution looks we’ll see of the famous hexagon until the 2040’s, as the northern pole enters winter and will shift into darkness for 15 years.

In Webb’s infrared observations, Saturn’s poles appear distinctly grey-green, indicating light emitting at wavelengths around 4.3 microns. This distinct feature could come from a layer of high-altitude aerosols in Saturn’s atmosphere that scatters light differently at those latitudes. Another possible explanation is auroral activity, as charged molecules interacting with the planet’s magnetic field can produce glowing emissions near the poles. 

Read more on the NASA Science website (original source).