3 ms·

If two forms of matter coexist in the same space but they do not interact in any way including inertia, are they separate universes?

anticensor 6y ago
It seems to.
subroutine 6y ago
I don't see how you could define separate universes as sharing the same space. The universe is the space, no?
- ganzuul 6y ago
  I'm not sure! I have thought about it a lot though. On one hand yes, it feels like it should be the same. On the other hand, it is not parsimonious to create another space when there is plenty of room left in this one. Should we define another universe as something which never has and never will interact with our universe? If so, anything we can observe of seemingly another universe is in actuality part of our universe. The topic seems like it could use a consensus about what the words it uses should mean and not mean.
  - subroutine 6y ago
    > If so, anything we can observe of seemingly another universe is in actuality part of our universe. Yes, this is how I would interpret the definition of THE UNIVERSE. My personal interpretation of "another universe" would be something like- a multidimensional vacuum populated with matter/energy that currently exists from our inertial frame of reference, and there is nothing linking our own sparsely populated vacuum to this other universe. i.e. if you can observe it, then it's not a different universe. As Penrose states, this is merely an earlier version of the same universe, which existed before the Big Bang. Here is a different prediction, a timelapse, of the fate of our universe (as told by Brian Cox), which assumes the universe will continue expanding... https://youtu.be/uD4izuDMUQA?t=10 https://youtu.be/uD4izuDMUQA?t=10
david-gpu 6y ago
> If two forms of matter coexist in the same space but they do not interact in any way including inertia How would you even know that matter is there? This looks like a non-falsifiable statement [0]. [0] https://en.wikipedia.org/wiki/Falsifiability https://en.wikipedia.org/wiki/Falsifiability
- ganzuul 6y ago
  That is part of the definition I suggested. If we knew it was there, then it would be part of our universe. It's a one-way valve on knowledge but I still think it is useful to define it. There is plenty of work to be done on the definitions. Should we like to, we could have a more rigorous natural language regarding observables by defining a boundary for where the physical universe begins and ends. Shrödinger's wave function does not appear to be part of the physical universe but yet we have an odd kind of observation of it in the form of experimental verification of theory. The space of theoretical physics then becomes part of the greater universe. I think Penrose's ideas warrant more precisely defined language.
czardoz 6y ago
I guess that depends on how you define "space"

anticensor 6y ago

It seems to.

subroutine 6y ago

I don't see how you could define separate universes as sharing the same space. The universe is the space, no?

ganzuul 6y ago
I'm not sure! I have thought about it a lot though. On one hand yes, it feels like it should be the same. On the other hand, it is not parsimonious to create another space when there is plenty of room left in this one. Should we define another universe as something which never has and never will interact with our universe? If so, anything we can observe of seemingly another universe is in actuality part of our universe. The topic seems like it could use a consensus about what the words it uses should mean and not mean.
- subroutine 6y ago
  > If so, anything we can observe of seemingly another universe is in actuality part of our universe. Yes, this is how I would interpret the definition of THE UNIVERSE. My personal interpretation of "another universe" would be something like- a multidimensional vacuum populated with matter/energy that currently exists from our inertial frame of reference, and there is nothing linking our own sparsely populated vacuum to this other universe. i.e. if you can observe it, then it's not a different universe. As Penrose states, this is merely an earlier version of the same universe, which existed before the Big Bang. Here is a different prediction, a timelapse, of the fate of our universe (as told by Brian Cox), which assumes the universe will continue expanding... https://youtu.be/uD4izuDMUQA?t=10 https://youtu.be/uD4izuDMUQA?t=10

david-gpu 6y ago

> If two forms of matter coexist in the same space but they do not interact in any way including inertia How would you even know that matter is there? This looks like a non-falsifiable statement [0]. [0] https://en.wikipedia.org/wiki/Falsifiability https://en.wikipedia.org/wiki/Falsifiability

ganzuul 6y ago
That is part of the definition I suggested. If we knew it was there, then it would be part of our universe. It's a one-way valve on knowledge but I still think it is useful to define it. There is plenty of work to be done on the definitions. Should we like to, we could have a more rigorous natural language regarding observables by defining a boundary for where the physical universe begins and ends. Shrödinger's wave function does not appear to be part of the physical universe but yet we have an odd kind of observation of it in the form of experimental verification of theory. The space of theoretical physics then becomes part of the greater universe. I think Penrose's ideas warrant more precisely defined language.

czardoz 6y ago

I guess that depends on how you define "space"