James Webb and Hubble reveal Saturn’s atmosphere in new images

Joint observations reveal Saturn’s structure, storms and jet streams at different altitudes

The James Webb Space Telescope (JWST) and Hubble Space Telescope have combined their capabilities to produce new views of Saturn across different wavelengths. Together, these observations give scientists a more detailed understanding of atmospheric activity on the gas giant.

Operating at visible wavelengths, Hubble records variations in the colours of Saturn’s clouds and hazes. James Webb, meanwhile, detects infrared radiation to examine the atmosphere’s chemical composition and structure at multiple altitudes. The combined results enable Saturn’s atmosphere and its layers to be studied as a three-dimensional system.

James Webb and Hubble track Saturn’s weather systems

JWST images reveal a jet stream in northern latitudes, produced by atmospheric waves. They also show remnants of the 2011–2012 “Great Springtime Storm”, along with several storms in the southern hemisphere. These features develop under the cloud layer through the influence of powerful winds and waves.

Saturn’s well-known hexagonal storm at its north pole, first discovered by Voyager in 1981, is visible in the images as well. Its persistence over several decades highlights the stability of major atmospheric processes on the planet. However, the next opportunity for close, detailed observations of this feature will not come until the 2040s, when the north pole is once again illuminated.

Infrared images show Saturn’s poles and rings

Infrared observations indicate that Saturn’s poles have a grey-green tint, potentially linked to aerosols high in the atmosphere or auroral activity - the equivalent of Earth’s “Northern Lights”. Such phenomena arise when charged particles interact with the planet’s magnetic field.

Saturn’s rings, which are composed of water ice, stand out particularly brightly in infrared images. Both views show the Sun-facing side of the rings, while their shadows fall across the planet. Differences in ring structure, including spokes and features within the B ring, demonstrate the distinctive strengths of each telescope.

Saturn observations follow the approach to the 2025 equinox

The 2024 observations, taken 14 weeks apart, record Saturn’s transition from northern summer towards the 2025 equinox. In future, the telescopes will be able to investigate the planet’s southern hemisphere as it becomes more strongly illuminated.

Hubble’s OPAL (Outer Planet Atmospheres Legacy) programme has monitored changes in Saturn’s atmosphere for more than a decade, including storms and seasonal shifts. James Webb supplements this record with infrared measurements, broadening the scope for studying the atmosphere’s structure and dynamics.