Saturn might be the planet in our Solar System best known for its spectacular rings, but the icy giant Uranus also has a system of 13 nested rings. Eleven of those rings—nine main rings and two fainter dusty rings—are clearly visible in the latest spectacular image from NASA's Webb Space Telescope. Future images should reveal the remaining two faint outer rings discovered with the Hubble Space Telescope in 2007.
"Uranus has never looked better. Really," NASA tweeted. "Only Voyager 2 and Keck (with adaptive optics) have imaged the planet's faintest rings before, and never as clearly as Webb’s first glimpse at this ice giant, which also highlights bright atmospheric features."
As we've reported previously, the Webb Telescope launched in December 2021 and, after a suspenseful sunshield and mirror deployment over several months, began capturing stunning images. First, there was the deep field image of the Universe, released last July. This was followed by images of exoplanet atmospheres, the Southern Ring Nebula, a cluster of interacting galaxies called Stephan's Quintet, and the Carina Nebula, a star-forming region about 7,600-light-years away. These images reportedly brought astronomers to tears.
Last August, we received gorgeous images of Jupiter, including the auroras at both poles that result from Jupiter's powerful magnetic field, as well as its thin rings and two of the gas giant's small moons. This was followed a month later by a mosaic image showing a panorama of star formation stretching across a staggering 340 light-years in the Tarantula Nebula—so named because of its long, dusty filaments. We also were treated to spectacular images of Neptune and its rings, which have not been directly observed since Voyager 2 flew by the planet in 1989.
In October, the Webb Telescope gifted us a spectacular new image of the Pillars of Creation—arguably the most famous image taken by Webb's predecessor, the Hubble Space Telescope, in 1995. And the very next month, the telescope gave astronomers fresh clues about the formation of a new star, with a stunning image of an hourglass-shaped dark cloud surrounding a protostar, an object known as L1527.
Uranus is the only planet in our Solar System that is tilted slightly on its side as it orbits. That unique tilt gives rise to more extreme seasons: 42 years of sunlight and 42 years of darkness over the course of its 84-year orbit around the Sun, per NASA. This image also captures a subtle brightening at the center of the planet's northern polar cap facing the Sun, as well as a couple of bright clouds that are likely the result of storm activity. The data collected by the Webb telescope should help solve the mystery of why this polar cap appears in the direct sunlight of summer but vanishes in the fall.
These enhanced polar features have not previously been seen by other powerful telescopes like Hubble or the Keck Observatory. But the Webb's primary imager, the Near-Infrared Camera (NIRCam), is well-suited to capture images of very faint objects. NIRCam's coronagraphs block any light coming from brighter objects in the vicinity, similar to how shielding one's eyes from bright sunlight helps us focus on the scene in front of us. So NIRCam boasts greater sensitivity and the ability to "see" longer wavelengths.
Listing image by NASA/ESA/CSA/STScI