One of Neptune's 16 moons is not like the others, James Webb telescope finds -- and it could be key to fully understandin

One of Neptune's 16 moons is not like the others, James Webb telescope finds — and it could be key to fully understanding the solar system


Neptune has a complicated life story, and its moon Nereid might be the only one left standing from the planet’s multibillion-year history.

By Elizabeth Howell
published 12 hours ago



Nereid (inset) may be the only moon of Neptune (background) that was around when the planet first formed, a new JWST study hints. (This composite image is not to scale).
(Image credit: NASA/JPL)


One of Neptune's largest moons has stuck around the neighborhood much longer than scientists previously thought — in fact, it may be the sole survivor of the planet's earliest days.

Nereid, Neptune's third-largest moon, is probably the only moon left over from when the ice giant formed early in the solar system's 4.5 billion-year history, a new analysis of James Webb Space Telescope (JWST) data suggests.

The results, published Wednesday (May 20) in the journal Science Advances, contradict the previous story about Nereid's history told in the decades since its 1949 discovery: that Neptune "captured" the 220-mile-wide (350 kilometers ) moon from an icy well of bodies in the outer solar system known as the Kuiper Belt.

JWST's observations were key to this realization, said first study author Matthew Belyakov, a graduate student in planetary science at Caltech. "What JWST did for Nereid is it confirmed that it had a lot of water ice, and gave us the overall shape of the spectrum [of light]," Belyakov told Live Science in a phone call.

More:
https://www.livescience.com/space/neptune/one-of-neptunes-16-moons-is-not-like-the-others-james-webb-telescope-finds-and-it-could-be-key-to-fully-understanding-the-solar-system