James Webb Telescope Captures Detailed Image of Uranus’ Rings

The James Webb Space Telescope has taken a stunning image of Uranus that showcases 11 of the planet’s 13 rings.

Made of rocks and dust that don’t reflect much sunlight, Uranus’ rings are not easy for most telescopes to pick up. Not only did Webb manage to capture them, but its shot is the clearest yet of the planet’s two fainter dusty rings. Until now, these ethereal rings had only been photographed by NASA’s Voyager 2 spacecraft, which flew near Uranus in 1986, and the Keck Observatory in Hawaii, per a statement from NASA.

“How amazing it is to see Uranus in the kind of detail that has only previously been possible by Voyager 2 actually visiting it,” Michael Merrifield, an astronomer at the University of Nottingham in England, tells New Scientist’s Alex Wilkins.

Scientists think that Webb will one day capture the planet’s remaining two faint outer rings not shown in this first image. The telescope is currently taking follow-up pictures of the planet.

Uranus, the seventh planet from the sun, does not have a solid surface. Its atmosphere is primarily hydrogen and helium with some methane, which absorbs sunlight’s red wavelengths and gives Uranus its blue-green appearance. The giant planet is about four times wider than Earth and consists of a small, rocky core surrounded by a hot, dense fluid of materials that includes water, methane and ammonia, per NASA.

As the distant planet orbits the sun once every 84 years, it completes its journey at a unique angle. Imagine the planets move along a flat surface as they orbit. Mercury rotates around an axis perpendicular to the imaginary surface, while most other planets rotate on an axis that’s slightly tilted—Earth’s tilt is 23.4 degrees. Uranus, on the other hand, is essentially tipped on its side, rotating at an angle of 98 degrees. As a result, one of its poles is bathed in continuous sunlight for long seasons, while the other faces the darkness of deep space.

When Voyager 2 flew by, it saw Uranus’ south pole basking in a summer sun, and the northern pole, captured by Webb, was on the planet’s dark side. In the new image, Uranus’ right side is covered by a white spot called a polar cap, which seemingly appears in the summer and disappears in the fall. Scientists hope Webb can help them determine why this happens, per NASA’s statement.

The image also contains two clouds likely connected to storm activity—one on the upper left side of the polar cap, and one on the far left of the planet.

With continued observation from Webb, scientists may be able to learn more about Uranus’ storms and environment. “Unlike Voyager’s flyby, we will be able to monitor its appearance over time to see what effect its strange tipped-over rotation might have on its weather patterns,” Merrifield tells New Scientist.

Webb orbits the sun from a point one million miles from Earth, but it’s just in our backyard compared to some of its far-off targets—the high-tech telescope has observed exoplanets, dying stars and distant galaxies that are changing ideas about the early universe. The new image of Uranus, snapped during a 12-minute exposure on February 6, was taken when Earth was 1.83 billion miles from the ringed planet, per Gizmodo’s Isaac Schultz.

The space telescope is the result of a collaboration between NASA, the European Space Agency and the Canadian Space Agency. It captured the new image with its Near-Infrared Camera (NIRCam), which can detect faint, far-away objects by blocking light from nearby, brighter objects with a coronagraph, per Ars Technica’s Jennifer Ouellette.

A wider view of the image shows the six brightest of Uranus’ 27 moons with other galaxies looming in the distance.

Will Sullivan | | READ MORE

Will Sullivan is a science writer based in Washington, D.C. His work has appeared in Inside Science and NOVA Next.