[Tornado220 (OP)]

I have driven my daughter mad with this question so maybe we could find an answer for the following question...  If the universe as we know it is expanding ?  what exactly is it expanding into?  what is the other side of 7.5 billion light years distance ??

[Kryptid]

As far as we can tell, it's not expanding into anything, it's simply expanding. It is technically possible that the Universe is expanding into a higher-dimensional "hyperspace", but it's not a necessary requirement. Just think of it as the amount of space in the Universe increasing over time.

[geordief]

This may be semantics but what about  "It is expanding into itself" ?

Does that  formulation of words make it easy to get one's head around the process  ? (as well as being,hopefully "correct"  )

[jeffreyH]

No one knows. We will probably never know. We can put forward hypotheses but cannot validate them through any kind of experiment. If particles exist that travel faster than light it may conceivably be possible to 'see' further than our observable limit. Until then there is no answer.

[timey]

Fact of the matter is that there is no validation that the universe is expanding.  Hypotheses have been put forward but to date no experiment has been devised to validate expansion.  If dark matter and dark energy were to be discovered this would validate the theory that describes expansion, because without dark matter and dark energy the theory that describes expansion is invalid.  So until dark matter and dark energy are discovered the question should really be "is the universe expanding" rather than 'what is the universe expanding into'...

[geordief]

Fact of the matter is that there is no validation that the universe is expanding.  Hypotheses have been put forward but to date no experiment has been devised to validate expansion.  If dark matter and dark energy were to be discovered this would validate the theory that describes expansion, because without dark matter and dark energy the theory that describes expansion is invalid.  So until dark matter and dark energy are discovered the question should really be "is the universe expanding" rather than 'what is the universe expanding into'...

Local expansion is verified by the fact that galaxies are all receding from one another (isn't it?) .Are you saying that global  expansion has not been verified?

Is the hypothesized global expansion a different beast to the  "local "expansion?

I seem to remember there used to be a steady state theory (Hoyle?) Is that theory definitively binned for all time  in a similar way to geocentrism ?

[timey]

Local expansion is verified by the fact that galaxies are all receding from one another (isn't it?)

No it isn't.  There is no experimental verification that galaxies are all receding from one another.  There is only Hubble's interpretation of the red shift/distance correlation that gives form to an interpretation of general relativity, an interpretation that requires that dark matter and dark energy be found to verify the hypotheses.

General relativity has other possible interpretations, one of which involves adding the cosmological constant for a steady state universe, the other of which involves not adding the cosmological constant for a universe that is contracting.
It is generally accepted in the world of physics that the steady state universe requires a balance that is improbable in the face of observation.
Hark that both of the other alternatives will follow the mathematics of general relativity, therefore all experiment that confirms general relativity will apply for an expanding universe and a contracting universe equally.

Because the recently (by comparison) realized theory of accelerated expansion requires an explanation, Einstein's cosmological constant that he added to general relativity to describe a steady state, and retracted in light of Hubble's red shift/distance correlation, has again become significant with regards to a value for dark energy.  A dark energy that is required mathematically to describe accelerated expansion.  A dark energy that remains, despite a lot of money being spent, nowhere to be found either in physical reality or by explanation of mechanics via theory.
The only avenue that has not been fully explored by experiment or via theory is that of a contracting universe, where a contracting universe would not require dark energy or dark matter, but would require re-interpretation of Hubble's interpretation of the red shift/distance correlation.

In any case, it is Hubble's interpretation of the red shift/distance correlation that has not been experimentally verified, and cannot be experimentally verified.  Therefore an expanding universe is not verified, nor unverified, and is just a hypotheses until dark matter and dark energy are experimentally verified to verify the expanding universe interpretation of general relativity as the principle theory.

[puppypower]

I have driven my daughter mad with this question so maybe we could find an answer for the following question...  If the universe as we know it is expanding ?  what exactly is it expanding into?  what is the other side of 7.5 billion light years distance ??

One of the conceptual problems with the expansion of the universe theory, is we infer the expansion through the red shift of the energy that the matter of the universe, once released. However, we can't directly measure the matter to make sure it is doing the same thing as the energy. We infer the motion of the matter from the energy signal but we do not measure the matter directly to double check this assumption.

The analogy is, a skunk sprays to avoid a predator and then runs away. Shortly thereafter, the smell from the skunk reaches us and continues to expand beyond us to the next group of people at the park. This expansion of the stink does not necessarily mean the skunk is heading toward us, since the odor, once released, acts independently of the skunk. We can measure the light; odor of the universe, but not the matter; skunk, since the matter; skunk, becomes detached after it releases the energy.

The light coming from galaxies a billion years ago, only tells us what the galaxy did 1 billion years ago. Like the skunk, it tells us nothing of what the matter of the galaxy is doing, today. Since the two are detached, today, the galaxy can be doing the opposite or the same. We can't conclusively infer from the detached energy.

What we do know is the most distant light has the most red shift. This means the matter of the universe, when it gave off that light; expanded the fastest, at the beginning; big bang. As we look at light closer in time to the present, the red shift of the detached energy decreases, and becomes a blue shift relative to the closest galaxy clusters. This describes an expansion, where the matter initially goes boom, but has the brakes on, from the beginning. The detached light does not have the same brakes.

Currently the assumptions behind the expansion attaches the matter to the energy, in real time. If that was true than an expanding universe would make sense.  It comes down to conceptual modeling assumptions.

Another analogous example is our sun is about 4.6 billion years old. It has been giving off energy and light for that long. Some of that light is billions of light years away from the sun in all directions. But the matter of the sun has not moved that far in any direction. The matter can never move in all direction billions of light years apart, like its detached energy, and still have sufficient mass density to maintain fusion. There are two separate things going on, once connected at point in time, but then detached the rest of the time.

[Tim the Plumber]

I might be able to provide the layman's best explaination on this. It might be wrong in a high level physics sense but then human language does not stretch to their stuff well.

If you play world of warcraft or some other such game and they add a new teritory to it it has expanded but since it has no external dimensions it is silly to think of it expanding into anything. Just does not make sense as a question.

The idea, as far as I am understanding it, plumber so..., is that if you were to mark a point in space, actualy attach something to the fabric of space (not at all possible but..) and the same at some other point 1m away and came back a couple of days later it would measure more than 1m. The space it's self is stretching.

It's like the game W of W-C is slowly making all the positions of the stuff in there be further and further appart. It used to take 10 minutes to get from A to B but now it takes 15.

Hope that works for you and your daughter.

[PmbPhy]

I have driven my daughter mad with this question so maybe we could find an answer for the following question...  If the universe as we know it is expanding ?  what exactly is it expanding into?  what is the other side of 7.5 billion light years distance ??

An expanding universe means that there is more and more space being created. As such its meaningless to speak of the universe as expanding into something. The question arises because our direct experience of nature with our senses tells us that if something is expanding then its expanding into space. But an expanding universe means that its space itself which is increasing, i.e. making more room.

[geordief]

I have driven my daughter mad with this question so maybe we could find an answer for the following question...  If the universe as we know it is expanding ?  what exactly is it expanding into?  what is the other side of 7.5 billion light years distance ??

An expanding universe means that there is more and more space being created. As such its meaningless to speak of the universe as expanding into something. The question arises because our direct experience of nature with our senses tells us that if something is expanding then its expanding into space. But an expanding universe means that its space itself which is increasing, i.e. making more room.

Can we usefully call it "internal space"?

Can we say there is no motion involved (and no kinetic energy)? After all this expansion never results in bodies colliding  where they would otherwise not have,does it?

[PmbPhy]

I have driven my daughter mad with this question so maybe we could find an answer for the following question...  If the universe as we know it is expanding ?  what exactly is it expanding into?  what is the other side of 7.5 billion light years distance ??

An expanding universe means that there is more and more space being created. As such its meaningless to speak of the universe as expanding into something. The question arises because our direct experience of nature with our senses tells us that if something is expanding then its expanding into space. But an expanding universe means that its space itself which is increasing, i.e. making more room.

Can we usefully call it "internal space"?

Can we say there is no motion involved (and no kinetic energy)? After all this expansion never results in bodies colliding  where they would otherwise not have,does it?

There is motion in the sense that if two bodies are at rest relative to each other the distance between them will increase with time just as two points on a rubber sheet will get further away from each other if the sheet is stretched.

[PmbPhy]

If the universe is expanding, what is it expanding into?

Universe is in equilibrium to Nothing Force maintaining balance. Now as we are explosions universe is expanding and not getting shattered due to time forms us and we are formed from electron by friction in space. I don’t say finite or non-finite universe. It is so electron moved in space by Nothing holding it due to friction even inside the electron Nothing is forming time we are in-time so see Universe expanding (even if we see electron it is same what we see as galaxies)through the telescope we know so could see electrons. Our instruments are based on time mirror too could be used as is past in time still universe shows expanding means has no destination so losing equilibrium is only possible if it doesn’t expand then only we could stay. Here title is expanding universe.

Welcome to the forum. First I'd like to ask why you responded to a thread in which nobody has posted in so long? Next I'd like to ask you to clarify what you posted above.

This being a science forum we make all attempts to adhere to the scientific method. In this case we respond by answering the question posed using currently accepted physics. If you have other ideas of how the universe works and wish to express them then this is not the right subforum for it. However we do have a subforum here entitled New Theories in which you are allowed to express and discuss your new ideas. Perhaps English is not your primary language and that's why I can't understand what you wrote. But statements such as

I read your response above. Unfortunately I can't make any sense out of it. I know that its not currently accepted physics. Its not even related to it. For example, the following sentences make no sense

Now as we are explosions universe is expanding and not getting shattered due to time forms us and we are formed from electron by friction in space.

Our instruments are based on time mirror too could be used as is past in time still universe shows expanding means has no destination so losing equilibrium is only possible if it doesn’t expand then only we could stay.

Would you care to elaborate for us please?

[PmbPhy]

Iamabout - Those are not based on currently accepted physics. The argument "I say .." does not constitute either a logical argument or a proper science argument.  As such you must post anything else on your "I say..."/belief/theory in the new theories section.

As far as The first thread I got suitable for my understanding I posted on it. goes I recommend that you first ask yourself what you hope to accomplish. This forum is for people to ask questions in the hope that others will answer them with currently accepted theories in physics (note: please don't confuse theory with speculation or belief. They don't mean the same thing). That means that in this forum we either ask a question or we post an answer to the best of our understanding of mainstream physics. If you have your own theory to post then I suggest that you post it in the New Theories section.

[paulggriffiths]

My words of wisdom are "...Space.Surrounds.Solid...".

The Big Bang may be an exploding star, PG

Enjoy!