Neptune's Moon Nereid May Be Original Companion, Study Reveals
Scientists have discovered that Neptune's moon Nereid may be one of the planet's original moons, surviving a cosmic collision that scattered other moons. Using NASA's Webb Space Telescope, a team led by the California Institute of Technology found that Nereid's composition is inconsistent with objects from the Kuiper Belt, suggesting it has always been part of Neptune's system. Nereid's eccentric orbit, which takes nearly a year to complete, supports the theory that it was pushed outward by the capture of Neptune's largest moon, Triton. This discovery challenges previous assumptions that Nereid was a captured object from the solar system's outskirts. 
