system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] Do the Nine Realms exist within the same plane of existence?

I've always been under the impression that the Nine Realms exist within different dimensions/planes (or at least not within the same physical space) and are only accessible to each other via the Bifrost or Asgardian magic/science.

However:

* Thor and the Asgardian refugees flee Asgard after Surtur destroys it
* Thanos finds their ship and destroys it
* The Guardians rescue Thor
* Thor, Rocket and Groot fly to Nidavellir
* They then use the Bifrost to get to Midgard

This suggests that at least Nidavellir and Asgard exist within the same space. Do we see anyone else going from one Realm to another via more conventional means, like regular space travel or the hexagonal jumpgates?

Is the Bifrost just a super-powerful teleporter, or does it bridge different dimensions/planes of existence?

Assuming an immortal was flying it, could the Milano fly to each of the Nine Realms without using magic?

EDIT: Just realized that, as far as we know, Peter Quill was born on Earth and has never travelled via Bifrost or other Asgardian magic, meaning Earth also exists within the same physical space as Asgard and Nidavellir as well.
gpt
In the MCU, yes, they all exist in our universe

The bifrost easily connects them,letting thee Asgadians rule 9 planets as easily as ruling 9 countries. With 9 planets of resources and a fraction of thee expenditure needed to rulee them, that's how they become such a powerful force.