What is space?

[stephen h]

tell what space is within the confines of the universe. discuss all aspects of space and how to identify space.

 

[Ibix]

That is a very broad question. What have you read so far? Why didn't the answer satisfy you?

 

[stephen h]

defining space will give us an idea of how large the universe is and how it might expand.

 

[PeterDonis]

defining space will give us an idea of how large the universe is and how it might expand.

We already have a detailed model of this in cosmology. Have you looked at it?

 

[stephen h]

That is a very broad question. What have you read so far? Why didn't the answer satisfy you?

in wikipedia what i have read describes space mostly in terms of matter plus cosmic radiation without mention of how they interact to form space or the universe.

 

[stephen h]

We already have a detailed model of this in cosmology. Have you looked at it?

yes and most references that is have seen are very general. the reference to cosmic radiation could be most revealing. the vast extent of the radiations (all types) far exceeds the imagination and is totally unmentioned and undescribed.

 

[PeterDonis]

in wikipedia

What page? Please give a specific link.

most references

What references? Be specific.

Have you read any actual textbooks or peer-reviewed papers on cosmology and our best current model of the universe?

Have you read any textbooks or papers on General Relativity, which is the theory we use to build our best current model of the universe?

 

[jbriggs444]

yes and most references that is have seen are very general. the reference to cosmic radiation could be most revealing. the vast extent of the radiations (all types) far exceeds the imagination and is totally unmentioned and undescribed.

If a phenomenon exceeds the imagination then perhaps it is time to adopt a mathematical description and reason logically from that. This is vastly preferable to reasoning from dreams and puffery.

 

[PeterDonis]

Have you read any actual textbooks or peer-reviewed papers on cosmology and our best current model of the universe?

Have you read any textbooks or papers on General Relativity, which is the theory we use to build our best current model of the universe?

@stephen h note that you marked this thread as "Graduate". If your answer to either of the questions I asked above is "no" (and I suspect your answer to both of them is "no"), then you don't have the background knowledge for a graduate level discussion of this topic. In any case, we need to have an idea of what, if any, background knowledge you do have.

 

[Ibix]

in wikipedia what i have read describes space mostly in terms of matter plus cosmic radiation without mention of how they interact to form space or the universe.

I think you are probably misunderstanding what you have read.

In relativity, space and time aren't completely distinct things - together they are a four dimensional thing we call spacetime. One dimension behaves differently from the other three, and that is the dimension we call time. You can (imagine) slicing spacetime into a stack of three dimensional "sheets", and each of those sheets is what we would call "space at one instant". There is, however, quite considerable flexibility in exactly how you choose to do this, just as there are many ways to slice a block of cheese into a stack of slices.

So far I've been talking generally. However, in the specific case of the spacetimes studied in cosmology, they are modelled as being filled everywhere with uniform density matter and radiation and datk energy. That choice of description naturally picks out a definition of space and time, and this is the bit I think you were trying to paraphrase. But the point is not that matter and radiation creates spaces, it's that it (in these models) gives you a natural choice of how to slice spacetime into a stack of space-at-an-instant slices.

 

[berkeman]

@stephen h note that you marked this thread as "Graduate". If your answer to either of the questions I asked above is "no" (and I suspect your answer to both of them is "no"), then you don't have the background knowledge for a graduate level discussion of this topic. In any case, we need to have an idea of what, if any, background knowledge you do have.

Since the OP has not responded to this, we have changed the level of the thread discussion to "High School".

 

[Drakkith]

in wikipedia what i have read describes space mostly in terms of matter plus cosmic radiation without mention of how they interact to form space or the universe.

Matter and radiation don't make up 'space', they exist within it.

A simple definition of universe is, per wikipedia: all of space and time and their contents. Matter and radiation make up the universe in the same way that marbles in a jar make up a jar of marbles.

 

[symbolipoint]

Space is a location expressible in three dimensions of length , width, depth.

note: Nearly all of us know that, and have known that since very early childhood but not everyone at all times know to express it in such a manner.

 

[berkeman]

@stephen h -- we definitely want to help you in your learning. Please start a new thread with links to your reading about your question. Asking such a broad question at a basic level is not usually going to work out well here. Find some links that talk about your question and use them to provide a better thread start. Thanks.