Thanks to the James Webb Space Telescope, people on Earth are gaining a completely fresh perspective on the rings of Neptune. Neptune and its gossamer diadems of dust appear to have an ethereal glow in an infrared photograph that was released on September 21. This image was taken against the backdrop of the darkness of space. The last close-up of the rings, which was shot more than three decades ago, cannot compare to the breathtaking photograph that was just recently taken of them.
It is quite difficult to observe Neptune’s rings from Earth because, in contrast to the brilliant bands that encircle Saturn, Neptune’s rings are very dim and dark in visible light. The last time anyone saw Neptune’s rings was in 1989, when NASA’s Voyager 2 probe shot a handful hazy photographs from almost 1 million kilometers afar after flying past the planet (SN: 8/7/17). The rings are depicted as narrow, concentric arcs in those photographs, which were captured in visible light.
Neptune’s rings disappeared once more as Voyager 2 resumed its journey into interplanetary space and did not reappear until July. At that time, the James Webb Space Telescope, also known as JWST, was approximately 4.4 billion kilometers distant from the planet when it aimed its acute infrared look toward the planet (SN: 7/11/22).
The planet Neptune itself looks to be predominantly shadowed in the latest photograph. Because of the presence of methane gas in the atmosphere of the planet, a significant amount of its infrared radiation is absorbed. The areas where high-altitude methane ice clouds reflect sunlight are indicated by a few brilliant spots.
And then there are the rings, which are never easy to find. Stefanie Milam, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and one of the JWST’s project scientists, says that the rings contain a lot of ice and dust, both of which are highly reflective in infrared light. “The rings have lots of ice and dust in them,” she says. The enormous size of the telescope’s mirror contributes to the instrument’s very crisp images. According to Milam, “JWST was built to look at the first stars and galaxies across the universe,” which enables humans to view fine features that were previously inaccessible to them.
In upcoming JWST observations, the planet Neptune will be examined using a variety of scientific instruments. According to Milam, this should reveal fresh information regarding the composition and dynamics of the rings, as well as regarding the development of Neptune’s clouds and storms. “Stay tuned for additional details.”