system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU, Thor] So how exactly do the nine realms work?

Are these "Realms" literally in different states of existence? Like alternate universes? Does that mean Midgard is *just* Earth, or the entire dimension in which Earth is located.

Does the realm of Asgard have an entire dimension in it, filled with countless planets and people? If so, why do they give a shit what happens in Midgard?

Are they just simply different places in the Universe connected somehow? So why are there just *Nine* realms, out of countless millions?
gpt
The Nine Realms appear to be in the same physical universe (in the MCU at least). When the Dark Elves were on Earth battling Thor, Mjolnir attempted to follow Thor on a direct spatial path after Thor would pop in and out of the realms during the convergence. That strongly suggests that the Realms are all in the same universe, just many light years apart.