How Neptune’s Triton Destroyed Nearly All Of Its Moons
The largest moon around our last planet didn’t originate with Neptune.
When it comes to the moons of our Solar System, there’s only one planet that doesn’t fit in with our expectations: Neptune. For every other planet, there are two main ways that they acquired their moons:
- either moons arose as the result of a giant impact, kicking up debris that either fell back onto the main world or coalesced into one or more satellites,
- or their moons are left over from the formation of the Solar System, forming from a circumplanetary disk around a gas giant world.
Earth and Mars likely got their moons from giant impacts, along with large Kuiper belt objects with moonslike Pluto, Haumea, Eris, and Makemake. In fact, it’s speculated that giant impacts are the number one way that terrestrial, rocky worlds get their moons.
But for the gas giant worlds, their moons mostly formed from a circumplanetary disk early on, complete with large moons that all orbit in the same plane and a ring system to go along with them. Jupiter, Saturn, and Uranus all fit this picture, but Neptune is an outlier. It’s one large moon, Triton, appears to be a captured Kuiper belt object, and obliterated almost the entire Neptunian system in the…
