Spacetime and Matter Energy:

[beecee]

A while ago I came across a Q+A list compiled by Sten Odenwald for the "GP-B: Testing Einstein's Universe" site. The Q+A was as follows.....

https://einstein.stanford.edu/content/relativity/a11332.html

Quote

 

Can space exist by itself without matter or energy around?

No. Experiments continue to show that there is no 'space' that stands apart from space-time itself...no arena in which matter, energy and gravity operate which is not affected by matter, energy and gravity. General relativity tells us that what we call space is just another feature of the gravitational field of the universe, so space and space-time can and do not exist apart from the matter and energy that creates the gravitational field. This is not speculation, but sound observation.

 

The highlighted part I found confusing to say the least and so I E-Mailed Sten Odenwald. He replied soon after by apologising and saying it should be "do not" without the "can and".

OK, since we now have that cleared up, I will comment on the answer. Simply put, it seems to make a lot of sense to me, particularly with the generally accepted notion that our first fundamentals originated after the Superforce started to decouple a short time after the BB as pressures and temperatures started to drop. Yes I realize that we have no real empirical observational evidence for this, but on the other hand it does seem rather logical to extrapolate to that epoch as to what supposedly happened, given the current knowledge we have on physics and cosmology.

Also I am inclined to accept that many Q+A sites are more inclined towards the general lay populace and can be regarded as "pop science". Again though the answer noting the correction seems OK to me. Do others agree?

 

[StringJunky]

Space is volume and volume is a function of things. 

[beecee]

1 minute ago, StringJunky said:

Space is volume and volume is a function of things. 

Do you see the answer that spacetime cannot exist without the matter/energy within it as valid? I can't see a problem.

[StringJunky]

5 minutes ago, beecee said:

Do you see the answer that spacetime cannot exist without the matter/energy within it as valid? I can't see a problem.

I'm not knowledgeable enough to be contrary but it fits in with what I understand.

[Strange]

8 hours ago, beecee said:

Do you see the answer that spacetime cannot exist without the matter/energy within it as valid? I can't see a problem.

He says that space and space-time cannot exist apart from matter and energy. To me this means something different from "can't exist without".

[scherado]

11 hours ago, beecee said:

General relativity tells us that what we call space is just another feature of the gravitational field of the universe, so space and space-time can and do not exist apart from the matter and energy that creates the gravitational field

I do believe that the above comports with my version: "Time is the handmaiden of Matter." In other words (mine) whatever it is we decide 'Time' to be, it is inextricably tied to Matter and there is no observational reason to posit inert Matter. I have been attempting to convey just these very things. I don't broach the subject of "space" as any Matter must occupy a position, possessing that area; "energy" is implied within Matter that is not inert.

Edited October 2, 2017 by scherado

[beecee]

1 hour ago, Strange said:

He says that space and space-time cannot exist apart from matter and energy. To me this means something different from "can't exist without".

OK, good point...Perhaps I may have misinterpreted slightly then?

Can you elaborate on what you see as the differences between the existing "apart from" and "can't exist without" ? And do you have a problem with it either way? 

52 minutes ago, scherado said:

I do believe that the above comports with my version: "Time is the handmaiden of Matter." In other words (mine) whatever it is we decide 'Time' to be, it is inextricably tied to Matter and there is no observational reason to posit inert Matter. I have been attempting to convey just these very things. I don't broach the subject of "space" as any Matter must occupy a position, possessing that area; "energy" is implied within Matter that is not inert.

Time is obviously linked to space. Most cosmologists believe what I already said....ie the first matter [first fundamental particles] arose when phase transitions and false vaccums  during the decoupling of the superforce. 

[Strange]

51 minutes ago, beecee said:

Can you elaborate on what you see as the differences between the existing "apart from" and "can't exist without" ? And do you have a problem with it either way? 

I interpreted it more as "independently of"; in other words, there isn't a larger (empty) space which the universe expands into, or a static space within which space-time curves. But I may well be wrong, and it is an interesting perspective either way.

On. related note, a member of another forum answered the question "what is mass" with the answer "the curvature of space-time". In other words, in the same way that gravity is not a separate thing "caused" by curvature of space-time, mass is not a separate thing that causes space-time curvature. I thought that was an interesting perspective, too.

[scherado]

2 hours ago, beecee said:

OK, good point...Perhaps I may have misinterpreted slightly then? [I'm glad you agree.]

Can you elaborate on what you see as the differences between the existing "apart from" and "can't exist without" ? And do you have a problem with it either way? 

Time is obviously linked to space. Most cosmologists believe what I already said....ie the first matter [first fundamental particles] arose when phase transitions and false vaccums  during the decoupling of the superforce. 

Time is obviously linked to Matter no matter what cosmologists believe, until they give persuasive evidence or persuasive arguments. I will wait for either or both. Thank you.

[beecee]

8 hours ago, scherado said:

Time is obviously linked to Matter no matter what cosmologists believe, until they give persuasive evidence or persuasive arguments. I will wait for either or both. Thank you.

 An empty claim at best. In actual fact they have given both evidence and persuasive arguments, despite you ignoring same, and you nor anyone else will invalidate that on a science forum open to any Tom, Dick or Harry.

10 hours ago, Strange said:

I interpreted it more as "independently of"; in other words, there isn't a larger (empty) space which the universe expands into, or a static space within which space-time curves. But I may well be wrong, and it is an interesting perspective either way.

On. related note, a member of another forum answered the question "what is mass" with the answer "the curvature of space-time". In other words, in the same way that gravity is not a separate thing "caused" by curvature of space-time, mass is not a separate thing that causes space-time curvature. I thought that was an interesting perspective, too.

Interesting...I actually interpreted it as per matter arising from the false vacuums and phase transitions resulting from the decoupling of the superforce which as I understand it was inherent to spacetime. In other words, no spacetime, no superforce, no matter.

With the mass question you raised, I would have replied it is a measure of the amount of matter in a particular volume, and gravity simply as a property of the geometry of spacetime. 

[Strange]

There are zero-energy solutions to the Einstein field equations that describe space-time with no matter present -and one can see how space evolves over time in such models. Which seems to invalidate the claim that "time is obviously linked to matter".

[beecee]

10 minutes ago, Strange said:

There are zero-energy solutions to the Einstein field equations that describe space-time with no matter present -and one can see how space evolves over time in such models. Which seems to invalidate the claim that "time is obviously linked to matter".

Just as a thought experiment, if I could remove the singularity/mass from a BH, would the BH still remain a BH, that is, would it maintain its shape. What I'm thinking is that as there is in effect only one direction within a BH, (critically curved spacetime) how can any signal actually get back outwards towards the EH, telling it that the mass/singularity has gone? 

     Or could this after more thought be answered by the fact that spacetime is not curtailed by the absolute universal speed limit?  Does this invalidate Odenwald's answer re spacetime and matter?

Edited October 2, 2017 by beecee

[Strange]

1 minute ago, beecee said:

Just as a thought experiment, if I could remove the singularity/mass from a BH, would the BH still remain a BH, that is, would it maintain its shape. What I'm thinking is that as there is in effect only one direction within a BH, (critically curved spacetime) how can any signal actually get back outwards towards the EH, telling it that the mass/singularity has gone? 

There is the concept of a black hole which only exists because of the energy in the gravitational field - no "extra" mass. 

But, in your example, although it is non-physical I think an answer could be that removing the mass would change the space-time curvature that stops information escaping such that the information about the changed mass can escape.

[beecee]

2 minutes ago, Strange said:

There is the concept of a black hole which only exists because of the energy in the gravitational field - no "extra" mass. 

But, in your example, although it is non-physical I think an answer could be that removing the mass would change the space-time curvature that stops information escaping such that the information about the changed mass can escape.

Or perhaps as per my edited addition...."Or could this after more thought be answered by the fact that spacetime is not curtailed by the absolute universal speed limit?  Does this invalidate Odenwald's answer re spacetime and matter"?

[Strange]

14 minutes ago, beecee said:

Or could this after more thought be answered by the fact that spacetime is not curtailed by the absolute universal speed limit?

I don't think so; after all, gravitational waves travel at the speed of light.

15 minutes ago, beecee said:

Does this invalidate Odenwald's answer re spacetime and matter?

Don't think so. You remove the matter and the space-time curvature disappears (at light speed).

[beecee]

2 minutes ago, Strange said:

I don't think so; after all, gravitational waves travel at the speed of light.

Bingo! Of course!!

[scherado]

9 hours ago, scherado said:

Time is obviously linked to Matter no matter what cosmologists believe, until they give persuasive evidence or persuasive arguments.

 

50 minutes ago, beecee said:

In actual fact they have given both evidence and persuasive arguments

Do you claim that "they"--let's require only one--cosmologist, a cosmologist has given, shown, asserted, provided--any one of those--persuasive evidence that time exists in the absence of Matter? For that is precisely what I am denying is relevant never mind whether it is possible. If there's no matter, then there's no time; but isn't it preposterous to posit a scenario without matter? Yes it is. Yet, there are knuckleheads who will do just that.

[Strange]

1 minute ago, scherado said:

Do you claim that "they"--let's require only one--cosmologist, a cosmologist has given, shown, asserted, provided--any one of those--persuasive evidence that time exists in the absence of Matter? For that is precisely what I am denying is relevant never mind whether it is possible. If there's no matter, then there's no time; but isn't it preposterous to posit a scenario without matter? Yes it is. Yet, there are knuckleheads who will do just that.

https://en.wikipedia.org/wiki/Vacuum_solution_(general_relativity)

There is a significant list of "knucklehead" physicists there.

[beecee]

2 minutes ago, scherado said:

 

Do you claim that "they"--let's require only one--cosmologist, a cosmologist has given, shown, asserted, provided--any one of those--persuasive evidence that time exists in the absence of Matter? For that is precisely what I am denying is relevant never mind whether it is possible. If there's no matter, then there's no time; but isn't it preposterous to posit a scenario without matter? Yes it is. Yet, there are knuckleheads who will do just that.

 You have it arse up. Matter emerged from spacetime at a distinct time from t=0, as I have mentioned and as logically described based on current knowledge. And I see that Strange has again invalidated your erroneous claim. 

[scherado]

1 hour ago, beecee said:

 You have it arse up. Matter emerged from spacetime at a distinct time from t=0, as I have mentioned and as logically described based on current knowledge. And I see that Strange has again invalidated your erroneous claim. 

Who? What's the reason you didn't quote the putative invalidation? Point to the "invalidation", please, if you can't quote it. Thanks.

[Mordred]

2 hours ago, scherado said:

 

Do you claim that "they"--let's require only one--cosmologist, a cosmologist has given, shown, asserted, provided--any one of those--persuasive evidence that time exists in the absence of Matter? For that is precisely what I am denying is relevant never mind whether it is possible. If there's no matter, then there's no time; but isn't it preposterous to posit a scenario without matter? Yes it is. Yet, there are knuckleheads who will do just that.

You know Schelero perhaps your time will be better used, by learning basic physics.

Basic physics 101.

Time is the rate of change of events or duration.

So in order to have matter, their must FIRST be time for matter to form in the first place.

How can anyone think otherwise is 100 percent beyond me, unless they don't know how to think.

Quite frankly time must exist for a universe to form in the first place, let alone matter.

Not that time is some mysterious pixie dust that requires existence. It is simply a property that emerges with rate of change. 

Edited October 2, 2017 by Mordred

[beecee]

1 hour ago, scherado said:

Who? What's the reason you didn't quote the putative invalidation? Point to the "invalidation", please, if you can't quote it. Thanks.

Apologies, I was not aware of your reading/comprehension difficulties.

https://en.wikipedia.org/wiki/Vacuum_solution_(general_relativity)

Quote

 

In general relativity, a vacuum solution is a Lorentzian manifoldwhose Einstein tensor vanishes identically. According to the Einstein field equation, this means that the stress–energy tensor also vanishes identically, so that no matter or non-gravitational fields are present.

More generally, a vacuum region in a Lorentzian manifold is a region in which the Einstein tensor vanishes.

 

yes, as I said, you have it arse up.

[MigL]

At the risk of putting myself outside the universe again ( sorry Mordred )...
A hot early universe, even though absent of matter, still has the property of energy.
Energy gravitates, IE gives rise to curvature of any pre-existing geometry, and further, gravity, because of self-coupling, gives rise to further curvature.
The geometry is, of course, the co-ordinate system of three spatial and the time dimension.

And no, BeeCee you cannot remove the singularity from a BH. The Event Horizon is a property of the singularity, and you cannot have a naked singularity 

[beecee]

33 minutes ago, MigL said:

And no, BeeCee you cannot remove the singularity from a BH. The Event Horizon is a property of the singularity, and you cannot have a naked singularity 

Hmmm, is this worth a dozen(?) issues of Playboy magazine.  I was thinking more along the lines of what is left and the possible scenario I explained. or as per http://scienceworld.wolfram.com/physics/EternalBlackHole.html

Quote

 

Eternal Black Hole

				A massless black hole which is a stable topological structure held together by the nonlinearity of its gravitational field.

 

 

[Roger Dynamic Motion]

 

Spacetime and Matter Energy:

 

ask yourself  do you exist ? and do you take space with your body ?

Time Energy & Matter are indivisible !!