Neptune's Moon Nereid May Be Sole Survivor of Ancient Lunar Collision

A recent study suggests that Nereid, one of the 16 moons orbiting Neptune, is the only remaining moon from an ancient collision linked to Triton's capture. Published on May 20 in Science Advances, the research utilized infrared data from the James Webb Space Telescope collected in November 2024, along with computer simulations. Nereid, identified in 1949 by Gerard P. Kuiper, exhibits a unique light signature that sets it apart from Kuiper Belt objects, indicating it was not captured. The simulations reveal that Triton's capture caused Neptune's original moons to be gravitationally scattered, resulting in Nereid being propelled into its current elongated orbit. These discoveries shed light on the history of the early solar system.