If another universe isn't causally related to ours..

[Art_Vandelay]

Then in a sense, is it as good as non-existent?

 

There are two factors here. The first being that another universe, totally seperate from ours, will have no relation to our passage of time. So you can't really say that it occurs before, or after, or concurrently to our universe, since what we know as time only began with this universe. Is this correct?

 

The other is the concept of 'nothing', as described by Lawrence Krauss. That is, the idea that 'nothing' doesn't actually exist. We mere mortals cannot comprehend 'nothing', and there is nowhere in the observable universe that consists of 'nothing'. I would take that a step further and say that there is no such thing as non-existence. At least in a literal sense.

 

I kind of lost my train of thought while I was trying to word this.. Do you guys understand what I'm getting at?

[ajb]

If this other universe cannot in any way be detected, we do not have any influence on it nor it on our Universe, then in what sense does this other universe exist?

[michel123456]

If this other universe cannot in any way be detected, we do not have any influence on it nor it on our Universe, then in what sense does this other universe exist?

It depends whether you are talking about the Universe or the Observable Universe. I suppose if something is missing from the O.U., it can belong the the U., which means it is causaly connected but not detectable.

Edited November 18, 2012 by michel123456

[Art_Vandelay]

I think those are two different beasts. A universe that is causally related to ours has to have something more in common than one that isn't. i.e the arrow of time. Which presents another problem. If our arrow of time is exclusive to our universe and resultant of the big bang that created our universe, how can a different universe share it? Unless our big bang begat more than just one universe. In which case there is a categorical difference between one of our 'cousin' universes, and a universe that began with a different big bang in a different part of the meta-universe.

[Daniel Foreman]

How you look at the universe and other universes is key here and largely based on assumptions we can not prove.

 

If you assume that space in universal, and that every universe is a "bubble" of matter floating around in it, then you can most certainly go visit other universes in the same way you might travel between galaxies. And if such is true then one universe can most certainly affect another. If one collided with another, they might merge or destroy one another, or simply pass right through each other depending on how the whole mechanism works.

 

If you assume that space is not universal but merely a framework for a single universe to exist in, then you can consider something like string theory which basically has matter existing in the same area bit vibrating at different rates, only one kind of vibration can interact with another vibration at the same rate.

 

One might suppose that reality is nothing more than an on off state, and that it only exists in brief moments like a film, and between those moments other universes are given the chance to exist. Think of a Sin wave, at the peak of the wave our universe exists, but anything other than that peak state seeds our universe not exist. Well if you have a lot of other sin waves working at different rates and peaks, then there's no reason all these alternative universes can't exist within the space space as our own. To visit them all one would have to do is adjust their own frequency so to speak.

 

Another school of thought might be that other frameworks other than space exist. Our X Y and Z existence may be completely unique, and may not exist in any other universe in which case I fear any other universe would be impossible to visit.

 

Ultimately such questions are pointless. We can guess at how our universe started, and how it came to be in the first place. But at the end of the day until we have some kind of observable data anything is simple guess work. We have to work out how our own universe works first before starting to work out how anyone elses might!

[JohnStu]

Yes I understand.

 

In my view, the idea of true nothingness is comprehendable for this simple fact being true nothingness would not be comprehended.