[MrJones (OP)]

Been thinking about this lately, as i read another thread about the absolute vacuum, inside the known universe - where they came to the conclusion that there weren't really a possible way to get total vacuum.

But as the universe is expanding, the total outer galaxies must be travelling into nothing. I mean like a place where atoms, and all other kinds of particles, time and matter hasn't reached yet, that it could be possible for absolute vacuum to exist? This is just a theory i guess, haven't read or heard about it. But the fact that the universe is constantly expanding there must be outer galaxies, the front galaxies of the expansion or where ever the light has traveled to there must be a place where it hasn't reached yet - Do you think it could be possible for total vacuum to exist there?

[evan_au]

One popular theory of the expansion of the universe is that the galaxies are carried along by the expansion of space between the galaxies.
In this theory, there is no space "outside" the space where the galaxies reside, so there is no vacuum into which the galaxies are expanding.

This theory cannot be confirmed by direct observation, since it is thought that there are parts of space which are forever unobservable by us; they are moving away from us faster than the speed of light.

[Bill S]

Hi Mr J, welcome.

As a non-scientist I struggle with the idea of “outside the Universe”, and with the concept of “nothing”.

On another forum I was recently assured by a scientist that “nothing” now has such a specific meaning in science that we should use the term “absolute nothing” when we mean nothing at all.  Thus, Lawrence Krauss was able to say: “By nothing, I do not mean nothing….”

If there is absolute nothing outside the Universe, that does raise some serious problems.  However, in order to answer your question about an absolute vacuum, I suspect it would be necessary to find a consensus among scientists as to whether an absolute vacuum is something, nothing or absolute nothing.  I wish you luck with that.

[flr]

But as the universe is expanding, the total outer galaxies must be travelling into nothing.

They cannot travel into nothing because nothing is absence all at that exits.
Note that any real object that would go into nothing must simply dissapear into nothingness but the conservation of energy prevents it.

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If you attempt to conceive an 'interface' consisting of what you would call 'outer galaxies' and 'nothing' that that 'nothing'  is not nothing but rather 'something' that is part of universe but still not populated with galaxies. In  such case we may be imagining a universe made of matter clumped together and some empty space outside this clamp of matter. The expansion of space would then be a population of the empty space with galaxies. But that is incorrect and raises other questions. For example:  why our universe will be so heterogeneous that some part of space populated with matter and other regions are not populated?
Note: empty space is something and it is not  absolute nothing.
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If our life would be confined to the surface of a sphere, we will never find an 'edge'. If that sphere expands like a balloon when push air in it, then the distance between points on the sphere increases without any need for 'outer' objects to travel into 'nothing'.
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Thus, Lawrence Krauss was able to say: “By nothing, I do not mean nothing….”

Then why isn't he using 2 different words since he apparently suggest to have in mind 2 district concepts?
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If there is absolute nothing outside the Universe, that does raise some serious problems.

absolute nothing = not a thing exists.
If there is not a thing outside our universe, then all that exists is our Universe - which makes sense; why would that be a 'serious problem'?.
 

[MrJones (OP)]

Thanks for the reply's, makes alot more sense now.. :-)