The James Webb Space Telescope (JWST) took phenomenal images of Jupiter and recently provided a unique view of mars, next? Well, he just revealed a spectacular capture of the most distant planet in our solar system. The stunning image shows the rings, some of Neptune’s moons, and is the most detailed view of Neptune in over 30 years.
The amazing thing about this image is the beauty of the rings. NASA’s Voyager 2 is the only spacecraft to have visited Neptune up close, making a close pass in 1989 as it left the solar system. Some of Neptune’s rings had gone undetected since Voyager 2 passed. More than three decades later, JWST wows us with this spectacular image that not only shows the rings, but clearly shows Neptune’s faint dust lanes.
Webb’s Near Infrared Camera (NIRCam) also captured seven of Neptune’s 14 known moons. A very bright point of light stands out in this portrait of the icy planet, showing the characteristic diffraction spikes seen in many Webb images, but it is not a star. Rather, it is Neptune’s large and unusual moon, Triton. View and download the image at best quality here.
Unlike Hubble’s visible-light images, NIRCam produces images of objects in the near-infrared range between 0.6 and 5 microns, so Neptune does not appear blue to Webb’s instruments.
Neptune’s blue color in Hubble images is the result of the absorption of red light by the planets’ methane-rich atmosphere, combined with the same process of Rayleigh scattering that turns Earth’s skies blue. Methane absorbs red and infrared light so strongly that the planet is quite dark at those wavelengths Webb sees, except where there are clouds at high altitudes. These methane ice clouds are distinguished by bright streaks and patches, reflecting sunlight before it is absorbed by methane gas.
“It’s been three decades since we’ve seen these faint, dusty rings, and this is the first time we’ve seen them in infrared,” said in a press release Heidi Hammel, Neptune systems expert and interdisciplinary scientist on the Webb Telescope team. Webb’s extremely stable and accurate image quality can detect these very faint rings so close to Neptune.
NASA collaborators explain that, more subtly, a thin line of brightness circling the planet’s equator could be a visual cue for the global atmospheric circulation that powers Neptune’s winds and storms. The atmosphere sinks and heats up at the equator, and therefore shines brighter in the infrared wavelengths than the cooler surrounding gases.
“Neptune’s 164-year orbit means its north pole, at the top of this image, is out of sight of astronomers, but the Webb images suggest an intriguing glow in this area. A previously known vortex at the south pole is evident in Webb’s view, but for the first time Webb revealed a continuous band of high latitude clouds surrounding him.”
More than 30 times further from the Sun than Earth, Neptune is the only planet in our solar system not visible to the naked eye and the first to be predicted by mathematics before its discovery in 1846. This icy giant fascinates astronomers since its discovery in 1846.
Neptune orbits in the far, dark region of the outer solar system, so from its surface the Sun should appear small and dim. To give you an idea of how far away, light at noon on Neptune is similar to faint twilight on Earth (the light just before sunrise or sunset).
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