[AntonioLao]

Originally Posted by Profpat What about the void or oblivion?

I would say that they exist only for background dependence physical theories such as quantum mechanics and all superstring theories. General relativity is probably the only background independence theory that I know of.

[Profpat]

I know in theory there isn't suppose to be an " outside " of the universe, but conceptually I always thought outside was the void allowing the universe to expand. And once expanded into the void it becomes space.

Before I was born I think I was in oblivion and maybe that is where I'll go when I die.

[AntonioLao]

Originally Posted by Profpat in theory there isn't suppose to be an " outside " of the universe

On the contrary almost all theories presume that there is an outside and an inside giving the definition of density as mass per unit volume. But if spacetime structures are Hopf links then there is no outside or inside. On the other hand, where and when positive and negative Hopf links combined in even or odd numbers then and only then would energy and matter come into existence. Nevertheless, Hopf links are simply squares of energy.

[Profpat]

Well that's two things I learned today. Do physicists ever ponder if there is a void? I believe philosophers contemplate the void and oblivion.

[AntonioLao]

Originally Posted by Profpat physicists ever ponder if there is a void?

Yes, and that was before general relativity (GR). For those who understood GR they tried very hard to get away from a background dependence thought. For this reason, some believed that both quantum mechanics and quantum field theory are incomplete and must be revised into background independence theories.

[Profpat]

I had no idea that GR theory eliminated the void. I'm learning a lot today Antonio.

[AntonioLao]

Originally Posted by Profpat GR theory eliminated the void

Actually, GR explains the void as a dynamic spacetime continuum. And within this cosmic fabric can be found matter and energy. But my contention is that the different structures of this fabric that form matter and energy and the fabric itself is really squares of energy.

[Profpat]

Hi Antonio;

You being a math expert, can you tell me if you were to superpose 3 one dimensional strings ( or lines ) on top of each other, would you still have a one dimensional string or line?

[AntonioLao]

Originally Posted by Profpat can you tell me if you were to superpose

Unfortunately, the principle of superposition is not applicable for both intensive and extensive physical variables. For an example the extensive variable of temperature cannot be superposed.

[Profpat]

OK. What if I made a green line and on top of that I made a blue line such that now my line blue/green, Can that be done and would it still be a one dimensional line?