Actually I don't think the ring is spinning at all in its construction phase. It's not even in "space" yet. There's too much acting on the ring that would, in theory, slow the rotation of the ring down. Plus, if it was spinning, you would see the ark slowly "rotating" above you and you probably would have noticed it a little in the cutscene where it was being raised. Unless it is spinning SO slow that you don't notice it, but you can still see Halo rotate in the first game...

Actually, with that said, I'm wondering how the "gravity" of the ring is even happening. Is it real gravity, or is it due to the centripetal force? If you stay on Halo due to the centripetal force, then you wouldn't be on it because of the way the ring is pulling into you? But then you have true gravity of the ring which is caused by its mass. Although it is thin, it is not small, so idk. But you still have real gravity from The Ark, so...

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