Thread: Space

I'm trying to wrap my head around space. Based on the articles that I've read, at the moment before the bang, space didn't exist. Then, during the big bang, space was born inside and expanded and continues to do so today.

Albert Einstein's take on this matter was that if you remove matter and energy from the universe, you remove space as well.

I couldn't find anything on what happens to space if the universe ends up in a "big crunch". If and when that happens, will space retract?

'events' are what exist.
past events influence future events.
space is just a property of interacting events.

even 'empty' space is completely filled with events.

where there are no events there is nothing, not even space.

The Big Crunch is no longer considered a likely scenario. The acceleration of the universe isn't slowing, and is in fact increasing. What exactly would happen would depend on what kind of assumptions you made that would cause the Big Crunch to happen in the first place.

Originally Posted by granpa

'events' are what exist.
past events influence future events.
space is just a property of interacting events.

even 'empty' space is completely filled with events.

where there are no events there is nothing, not even space.

If you accept general relativity this is a meaningless tautology. Spacetime points are, by definition "events".

If you do not accept GR it is gibberish.

events dont have to interact in space-like ways.
they can interact in other ways too.
look at entanglement

It seems to me that space must be infinite and yet at the same time it seems to me that space must not be infinite. The question is either what would limit space so that it is not infinite or how could infinite space extend forever in all directions? The possiblity of space extending forever in all directions seems non existant while at the same time the possiblity of a limit to its size is even less so. Perhaps it is just the limits of my mind that does not allow me to see how an infinite amount of room can physically exist or how it can not.

Originally Posted by granpa

events dont have to interact in space-like ways.

To do so would violate causality.

Do you have any idea what you have actually said ?

Originally Posted by granpa

they can interact in other ways too.
look at entanglement

huh ?

The collapse of the wave function for entangled particles actually is a relationship between twp points with a spacelike separation. That was the whole point of the EPR thought experiment, since confirmed by a real experiment..


It is pretty clear that you have no idea what you are talking about.

it doesnt violate causality.
But it does require that there be a universal 'now'.
relativity dosnt say that there cant be a universal now.
relativity just says that there is no experiment by which we can detect it.

Moreover if space is fundamental then why exactly 3 dimensions?
Why not 1000 or 1,000,000 dimensions?
Why not 10^1000 dimensions?

If there is no experiment that can detect it, even indirectly, then for all intents and purposes, it doesn't exist to science.

Originally Posted by granpa

it doesnt violate causality.
But it does require that there be a universal 'now'.
relativity dosnt say that there cant be a universal now.
relativity just says that there is no experiment by which we can detect it.

Moreover if space is fundamental then why exactly 3 dimensions?
Why not 1000 or 1,000,000 dimensions?
Why not 10^1000 dimensions?

This is somewhere between ridiculous and just plain gibberish.

Originally Posted by granpa

it doesnt violate causality.
But it does require that there be a universal 'now'.
relativity dosnt say that there cant be a universal now.
relativity just says that there is no experiment by which we can detect it.

Moreover if space is fundamental then why exactly 3 dimensions?
Why not 1000 or 1,000,000 dimensions?
Why not 10^1000 dimensions?

This is somewhere between ridiculous and just plain gibberish.

Originally Posted by granpa

it doesnt violate causality.
But it does require that there be a universal 'now'.

It seems you think that quantum entanglement requires that there is a universal 'now' (or absolute simultaneity). I can understand how you might have come to this conclusion, based on the popular descriptions of quantum entanglement.

But, what would you say if I told you that, rather than requiring anything as seemingly intuitive as a universal 'now', it has been shown experimentally, and repeatedly, that the influence of quantum entanglement works backwards through time?

You should research into "The Delayed Choice Quantum Eraser" experiment.