The problem with discussing other universes is that you can never know anything about them. You are free to postulate your own ideas as to what such a place might be like, and no-one can ever gainsay you.
The whole point is that if you have even the slightest knowledge of "another" universe, then it immediately becomes part of your / this universe.
There is absolutely no reason to suppose that another universe would have concepts such as mass, time, gravity ... or anything we are familiar with.
Any knowledge you have is inside your brain and therefore part of you, part of this planet, part of this universe.