If there was a creature so large that our universe was microscopic to it. Would it’s version of light travel at a speed relative to it’s size? Or does the speed of light make such things an impossibility.
How it perceives the speed of light or the actual speed of light?
Nope, c is a constant. Even with a gigantic thing the size of a galaxy (universe is bigger but how can something exist that’s bigger than the universe?) the limitation on the speed of light is independent of the size.
Light would be useless to something that size I would think because it would be too slow.
Huh??
I am trying to comprehend your question. I think you are asking about the cosmological “scale factor”?
The speed of light you can always just set equal to 1. Now, if the universe has a de Sitter shape, for example, then it has a scale factor that exponentially increases in time. That means that non-accelerated objects will grow increasingly faster apart, eventually faster than the speed of light, and what you would obverse is an event horizon beyond which you can never see or learn any information.
The creature described in the OP could not exist in our universe. Its own universe would necessarily have different laws of physics that would allow it to exist (and thus a different speed of light).
That’s the point. You’re postulating a living creature that could not communicate internally, because light is a constant and it would take billions of light years for any message controlling it to get to its end. It would be a huge bunch of totally separated kingdoms at best, not a gigantic individual.
Some thought experiments illume physics; others are just outside them.
I think DPRK essentially has a right. In and of itself the speed of light doesn’t pose a insurmountable challenge, you just have to have the creature live on a time scale slow enough to be commensurate with its size. The thing that kills it is dark energy. The creature’s time scale will be so slow and its size so large that it will expand into oblivion before it realizes it exists.
Yes I can imagine him taking a step that takes over a trillion years to complete
I recall reading a speculation on this very subject. The basic observation is that the free energy of the universe will never be exactly 0 and that computation requires some free energy, but there is no minimum, although the less there is, the slower it will have to be. The speculation imagined that giganitic but exteremely slow organisms could exist even as the universe approaches its entropy death. As for dark matter, maybe it all decays in 10^{125} years which is what the speculation was about.
For similar reasons one could imagine extremely small, extremely fast organisms in the first 10^{-100} seconds after the big bang to whom our universe represents their entropy death.
Exactly we would have no hope of ever observing the super large or even detecting it for that matter. The small would probably be equally unobservable.