Triton likely formed in the outer solar system before Neptune captured it, largely destroying the planet’s original moon system. JWST observations published in July 2026 suggest today’s inner moons re
New research using the James Webb Space Telescope suggests that Neptune's current moon system was formed after the capture of Triton, which destroyed the planet's original moons. The findings indicate that inner moons were rebuilt from the debris of these destroyed bodies.
Why it matters
Understanding the formation of planetary systems provides critical insights into the history and evolution of our solar system.
Webb spectra suggest Neptune’s inner moons were rebuilt from destroyed icy interiors, while separate evidence casts eccentric Nereid as a possible original survivor.
Published September 6, 2026 · How we edit
Neptune has 16 known moons, yet it barely has a conventional moon system at all. Triton alone contains more than 99 per cent of the satellite system’s mass, travels backwards around the planet and leaves only a compact collection of small inner moons, faint rings and distant irregular companions.
That peculiar architecture has long pointed to an ancient catastrophe. Triton probably formed elsewhere in the outer Solar System and was captured by Neptune, entering on an orbit that destabilised the moons already there.
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