Neptune’s Original Moon Nereid Survives Cosmic Collision

Neptune’s distant moon, Nereid, may be a remnant of the planet’s original moons that survived a violent cosmic event. Scientists have observed Neptune’s moons with the Webb Space Telescope, revealing new insights. Sixteen known moons orbit Neptune, the eighth and farthest planet in our solar system. Triton, the largest moon, disrupted the original moons billions of years ago, sending them on paths that led to collisions.

The research team, led by the California Institute of Technology, used this advanced telescope to study Nereid. According to their findings, Nereid likely avoided such collisions, maintaining a unique elliptical orbit around Neptune. “We have limited knowledge of Nereid compared to its size,” said study author Matthew Belyakov of Caltech.

Nereid was discovered by Dutch astronomer Gerard Kuiper in the 1950s. This moon carries the name of sea nymphs from Greek mythology. Nereid’s orbit is highly unusual, taking nearly an Earth year to complete one loop around Neptune. This orbit ranges from less than 1 million miles (1.4 million kilometers) to 6 million miles (9.6 million kilometers) from Neptune.

The research challenges previous assumptions that Nereid migrated from the Kuiper Belt, a distant region of icy bodies. Using the Webb telescope, scientists found that Nereid contains too much ice to fit this theory, suggesting it has been part of Neptune’s system from the start.

Previous missions, such as Voyager 2, provided early glimpses of Neptune in 1989, but recent observations offer clearer insights. The latest findings were published in the journal Science Advances. The study’s findings indicate that Nereid’s orbit aligns with the idea that it formed near Neptune and was later pushed outward due to Triton’s influence.

Belyakov and his team propose that Neptune’s inner moons might have formed from the debris of the original moons, which were destroyed by Triton’s intervention. In contrast, other giant planets have more moons, with Saturn leading at 292.

To fully understand Neptune’s moons, experts believe that a spacecraft mission is necessary, though none are scheduled. The Associated Press notes that the Health and Science Department receives aid from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation.