Saturn's new face captured by two space telescopes

NASA's James Webb Space Telescope (JWST) and the Hubble Space Telescope collaborated to release new images of Saturn. The two telescopes are providing scientists with a richer, more multi-layered understanding of Saturn's atmosphere by observing different wavelengths of light.

Hubble captured sunlight reflecting off Saturn's band-shaped clouds and haze, revealing subtle color changes. Meanwhile, Webb's infrared observations detected clouds and chemicals at a variety of depths, from deep cloud layers to the thinner upper atmosphere. Through this, scientists can effectively 'cut' and analyze Saturn's atmosphere at various altitudes, like peeling an onion.

The story of Saturn as told by Webb and Hubble

One of the key features captured in these observations is a long-lived jet stream known as a 'ribbon wave'. This air current meanders across the mid-latitudes of the Northern Hemisphere and is influenced by atmospheric waves that are not detectable with the naked eye.

Below it, remnants of the 'Great Springtime Storm' that occurred between 2010 and 2012 remain in the form of small dots. Web images also show several other storms scattered across Saturn's southern hemisphere. These features are formed by powerful winds and waves beneath the visible cloud layer, making Saturn a natural laboratory for studying hydrodynamics under extreme conditions.

The last high-resolution image of the hexagonal jet stream discovered in 1981.

Some of the sharp edges of the iconic hexagonal jet stream at Saturn's north pole, discovered by NASA's Voyager spacecraft in 1981, are faintly visible in both images. Lasting for decades, this phenomenon remains one of the solar system's most interesting weather patterns and shows how stable certain large-scale atmospheric processes on the giant planet are.

Scientists believe this observation will be the last opportunity to see the famous hexagon in high resolution until the 2040s. As the North Pole enters winter, it will be immersed in darkness for the next 15 years.

Secrets of Saturn's polar regions revealed by infrared light

Webb's infrared observations showed that Saturn's polar regions have a distinct gray-green color and emit light with a wavelength of 4.3 microns. This feature may be due to the high-altitude aerosol layer in Saturn's atmosphere scattering light differently at that latitude. Another possibility is auroral activity, where charged molecules interacting with the planet's magnetic field can cause glowing emissions near the poles.

NASA's Hubble and Webb have already explored Saturn's aurora and have also provided insight into Jupiter's spectacular aurora. In addition, we confirmed the aurora on Uranus, which was first captured by Hubble in 2011, and achieved the first detection of the aurora on Neptune through the web.

Saturn's rings shining with ice

Saturn's rings shine very brightly in Webb's infrared image. This is because it is composed of highly reflective water ice. Both images show the sun-facing side of the ring, with the Hubble image showing a shadow on the planet's surface beneath the ring.

Subtle ring features, such as spoke and B ring (the ring's thick central region) structure, also appear different between the two telescopes. The outermost ring, the F Ring, appears thin and sharp in the Web image, but only faintly glows in the Hubble image.

The Hubble image was taken in August 2024 as part of the 'OPAL (Exoplanet Atmosphere Legacy)' monitoring program that has been ongoing for more than 10 years. Web images were taken several months later during the director's discretion. The two observations complement previous observations by NASA's Cassini orbiter, which studied the Saturn system from 1997 to 2017.