The James Webb Telescope (JWT) has returned spectacular new imagery of planet Neptune. Most striking in Webb’s new image is the crisp view of the planet’s rings – some of which have not been detected since NASA’s Voyager 2 became the first spacecraft to observe Neptune during its flyby in 1989.
Key points
- In addition to several bright, narrow rings, the Webb image clearly shows Neptune’s fainter dust bands.
- Webb’s Near-Infrared Camera (NIRCam) images objects in the near-infrared range from 0.6 to 5 microns, so Neptune does not appear blue to Webb.
- In fact, the methane gas so strongly absorbs red and infrared light that the planet is quite dark at these near-infrared wavelengths, except where high-altitude clouds are present.
- Webb also captured seven of Neptune’s 14 known moons, the most significant of which is Triton. It appears star-like in the Webb imagery.
- That’s because Neptune is darkened in the telescope’s view by methane absorption at infrared wavelengths.
- Triton, on the other hand, reflects an average of 70% of the sunlight that strikes its icy surface. It’s very bright.
About Neptune
- Neptune was discovered in 1846.
- Neptune is the outermost planet in our Solar System, beyond Uranus and Saturn, but inside the dwarf planet Pluto.
- It circles the Sun at a distance of roughly 4.5 billion km, and takes 164.8 years to complete one revolution.
- Located 30 times farther from the Sun than Earth, Neptune orbits in the remote, dark region of the outer solar system.
- This planet is characterized as an ice giant due to the chemical make-up of its interior. Compared to the gas giants, Jupiter and Saturn, Neptune is much richer in elements heavier than hydrogen and helium.
- The ice giant Neptune was the first planet located through mathematical calculations. Using predictions made by Urbain Le Verrier, Johann Galle discovered the planet in 1846. The planet is named after the Roman god of the sea, as suggested by Le Verrier.
- Neptune has at least five main rings and four prominent ring arcs that we know of so far.
- Starting near the planet and moving outward, the main rings are named Galle, Leverrier, Lassell, Arago, and Adams. The rings are thought to be relatively young and short-lived.
- Neptune’s ring system also has peculiar clumps of dust called arcs. Four prominent arcs named Liberté (Liberty), Egalité (Equality), Fraternité (Fraternity), and Courage are in the outermost ring, Adams.
