Neptune's moon Nereid might be the only satellite surviving from the planet's original system, researchers report in a new study.
This goes against the previous theory, which has long suggested that Nereid is actually an object captured from the Kuiper Belt, the ring of icy bodies beyond Neptune's orbit. In the early history of the outer solar system, it was chaos. Neptune's gravity is thought to have captured its largest moon, Triton, from the vast disk of the Kuiper Belt, which is home to countless small bodies, including a number of dwarf planets. This capture wreaked havoc on the Neptune system and, until now, it's been thought that the planet's third-largest moon, Nereid, was also an object captured from the Kuiper Belt. But a new paper begs to differ.
