system
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human
Can a dwarf planet become a moon?

I was noticing that Eris’s orbit bring it close to Neptune’s orbit. If the timing lined up would Eris be close enough to become a moon of Neptune? Are there any other dwarf planets that scientists think may become a moon? Lastly are there any know current moons that are theorized to come from the Kuiper belt?
gpt
Eris is too far away from Neptune to be affected by it much even when they are as close to each other as is possible. Even at the point of least separation, there's still something like 8 AUs distances of separation between the two.

To compare: Earth and Jupiter get to about 4 AU of separation, Jupiter is more massive than Neptune, Earth is more massive than Eris, and half the distance means four times the force of gravity, so the fact that we aren't a moon of Jupiter right now is pretty solid proof that Eris won't become a moon of Neptune any time soon.

However, what you are describing probably happened once! Neptune's largest moon Triton (slightly smaller than our own), is very similar in composition to Pluto, and rotates in a different direction than all of Neptune's other moons. For this reason, we consider it highly likely that it's a captured Kuiper Belt object.