Decades of observations have revealed the true nature of this mysterious world. Astronomers have been able to detect Neptune’s chemical makeup and observe a massive planet-sized storm in its atmosphere.
Data from the Voyager 2 flyby also confirmed the presence of a faint ring system and a group of dust lanes called arcs, which are thought to be sculpted and sustained by the gravitational influence of the nearby moon Galatea.
Now, a new image from the powerful James Webb Space Telescope gives us the best view of Neptune’s rings since Voyager 2 visited the distant world 30 years ago.
The new images were taken using Webb’s near-infrared camera (NIRCam). In the infrared part of the spectrum, Neptune’s rings reveal themselves as a set of well-defined rings surrounding the ghostly planet, punctuated by swarms of diffuse dust lanes.
Seven of Neptune’s moons can also be seen dotting the image, including the brightly glowing form of Tritan that dominates the upper part of the vista. Neptune’s largest natural satellite orbits its host planet in the opposite direction to the ice giant’s other moons, a so-called retrograde orbit.
Scientists believe that Tritan was once a roaming asteroid that traversed the Kuiper Belt, a distant icy debris field surrounding our star. However, at some point in ancient times, the rover was caught by its powerful gravity because it was too close to Neptune.
Today, Triton is enveloped in a layer of frozen nitrogen, which allows it to reflect about 70 percent of the sunlight that hits its surface. Because of this, it is able to outshine the mighty Neptune, even though it is smaller than Earth’s moon.
Neptune’s apparent dimness in the new image has also been attributed to its atmospheric composition. Methane, which is present in its upper atmosphere, is very good at absorbing red and infrared light from the sun and reflecting other wavelengths. That’s why the planet appears blue in visible-light images captured by the Hubble Space Telescope.
However, these same infrared absorption properties make much of Neptune’s surface relatively dim in the new JWST portrait. That said, bright high-altitude cloud bands and a prominent storm can be seen meandering across the alien world’s surface.
A brighter band of faint infrared light is also visible near the equator, marking areas where atmospheric ice clouds fall to the surface and heat up.
JWST will turn its attention to Neptune again later this year. Be sure to check out IGN’s science page for all the biggest and weirdest developments in space exploration.
Anthony Wood is a freelance science writer at IGN