Properties of space

[lesliedellow]

The "space" that we live in doesn't do any expansion tricks which causes the distances to be greater between various objects on a constant basis.

I'm not particularly interested in your philosophical problems with General Relativity.

The "space" that you're talking about is *nothing like* the "space" that we experience on Earth.

The space I am talking is Euclidean and has three dimensions.

 

[Michael]

I'm not particularly interested in your philosophical problems with General Relativity.

Space expansion is *optional* in GR, and therefore my philosophical problem isn't with GR, it's with your *assumed* cause/effect claim with respect to photon redshift.

The space I am talking is Euclidean and has three dimensions.

Ok.

 

[Resha Caner]

The perpendicular axes provide a frame work to describe how particles through space, but it isn't an actual property of space.

Yes, that's essentially what I've been trying to say.

 

[Resha Caner]

No. It's definitely not neither on some scales and definitely neither on others. It's a question of whether if something is for all practical purposes indistuinguishable from something else, whether it is that. This is a subtle question. If you have two objects that to all measurement processes known are the same color, are they the same color? At what point do we split hairs? The Planck length?

Presently we think we live "in" (not the best word but it'll do) something that described approximately (very very very very well) by Riemannian geometry on very very big scales. We know that isn't the entire picture, because it simply can't be thanks to quantum mechanics...

We also live "in" something that approximates very very very very very well to a Euclidean geometry metric. On certain scales, indistinguishable from Euclidean...it's all a question of scale and whether deviation is detectable...

Hmm. Though it seems you started off disagreeing with me, by the end you were saying much the same as me. Given that Riemannian space works in one scenario and Euclidean space in another, I don't see how we can say either describes a property of space. So, the answer is: neither.

That says nothing of how effective those models are. They can be very effective at problem solving. But that wasn't the question. The question was: What are the properties of space?

 

[Michael]

The perpendicular axes provide a frame work to describe how particles through space, but it isn't an actual property of space.

 

[Resha Caner]

We are talking about the space we live in.

OK, so our conceptual constructs are just that - conceptual constructs.

None of which alters the fact that there are three spatial dimensions.

For the spatial concepts you're willing to accept. Why are you rejecting a 4 DOF description that can touch every point in space just as your description can?

And since we're talking about real space, have you ever seen it? Heard it? Felt it? Tasted it? How are you perceiving this thing you're calling space?

I am saying that the dimensionality of a vector space is DEFINED as being the number of linearly independent vectors it can play host to.

Sure. I never questioned how you're defining space. But aren't definitions human constructs? How do you make the link that this definition is a property of (real) space?

 

[Radagast]

The curious thing about space is that it seems to have certain definite properties of its own. For example, it is three dimentional. If it is just nothing, why can't you erect as many mutually perpendicular axes as you like?

Space isn't "nothing," it has structure. In particular it's inherently 3-dimensional. That's why, for example, radiation intensity drops off as the square of the distance.

 

[Justatruthseeker]

The curious thing about space is that it seems to have certain definite properties of its own. For example, it is three dimentional. If it is just nothing, why can't you erect as many mutually perpendicular axes as you like?

3 dimensions are merely measurements to objects, or of objects "within" space, not a measurement of space itself. You can not measure space, merely the distance between objects that exist within that space, or to a specific location in that space.

They are X, Y and Z coordinates, You could add more, but why add complexity to a coordinate system that can locate any point with 3 numbers?

 

[Justatruthseeker]

Hmm. Though it seems you started off disagreeing with me, by the end you were saying much the same as me. Given that Riemannian space works in one scenario and Euclidean space in another, I don't see how we can say either describes a property of space. So, the answer is: neither.

That says nothing of how effective those models are. They can be very effective at problem solving. But that wasn't the question. The question was: What are the properties of space?

According to E, they are the properties of an aether that can not be endowed with physical movement, despite that everyone wants to do just that.

Einstein: "Ether and Relativity"

Sort of like a - voltage field - i.e. vacuum energy, Higg's field, etc, etc. A voltage field can cause movement, but itself does not move.

 

[Justatruthseeker]

Space isn't "nothing," it has structure. In particular it's inherently 3-dimensional. That's why, for example, radiation intensity drops off as the square of the distance.

No, radiation intensity drops off as the square of the distance because the distance between particles becomes larger, allowing less photons to strike the same surface area. No magical bending, expanding, accelerating nothing need be invoked.

 

[lesliedellow]

Space expansion is *optional* in GR, and therefore my philosophical problem isn't with GR, it's with your *assumed* cause/effect claim with respect to photon redshift.

Ok.

Space has to be expanding or contracting. The knife edge condition where it is static is not on the menu. The slightest burp, and it would fall off the knife edge.

 

[lesliedellow]

That's why, for example, radiation intensity drops off as the square of the distance.

You might want to point that out to Resha Caner, and justatruthseeker. Still, the really interesting question is, what is this thing, which isn't just nothing, "made of?" To put it that way is problematic, but it illustrates the problem.

 

[Michael]

Space has to be expanding or contracting. The knife edge condition where it is static is not on the menu. The slightest burp, and it would fall off the knife edge.

That's ultimately a statement on faith on your part because "space" doesn't *have* to do anything, and it *doesn't* do any such thing here on Earth. GR would imply that spacetime (as in object movement) as a whole may "have" to expand or contract without a non zero constant, but "space" doesn't have to do anything. You're confusing object movement with "space expansion" in terms of what GR actually suggests.

 

[Strathos]

I thought it was four dimensional

 

[lesliedellow]

That's ultimately a statement on faith on your part .

That is a statement of fact, which follows from the mathematics of GR. Unless you want to follow in the foot steps of your colleague, who never seems able to decide whether he accepts Einstein's theory or not.

 

[lesliedellow]

I thought it was four dimensional

Spacetime might be four dimensional. Space is three dimensional.

 

[Justatruthseeker]

That is a statement of fact, which follows from the mathematics of GR. Unless you want to follow in the foot steps of your colleague, who never seems able to decide whether he accepts Einstein's theory or not.

Where does GR apply except in describing the orbits of solids, liquids and gasses? Name one other place - without adding 95% ad-hoc Fairie Dust even though you claim the laws of physics are the same everywhere.

You just wont face up to the facts that 99% of the universe is plasma (charged matter), not solids, liquids and gasses (neutral matter - balanced electromagnetically), to which GR describes just fine. Which is why you require that 95% ad-hoc Fairie Dust, because you continue to treat plasma like solids, liquids and gasses - in your conceptual models - an impossibility in any laboratory experiment ever done.

GR is an excellent theory, for describing how neutral matter behaves - 1% of the universe - solar systems. But that choice of coordinates in your pseudo-tensor, makes it irrelevant everywhere else.

Pseudotensor - Wikipedia, the free encyclopedia

It's simply your refusal to accept that GR only describes the behavior of solids, liquids and gasses - not plasma. And hence it fails outside the solar system in a universe of 99% plasma. But rest assured, it would hold in any other solar system as well, of that I have no doubts. Stop trying to apply the behavior of solids, liquids and gasses to a state of matter that behaves nothing like them, 95% different.

 

[lesliedellow]

You just wont face up to the facts that 99% of the universe is plasma (charged matter), not solids, liquids and gasses (neutral matter - balanced electromagnetically), to which GR describes just fine. Which is why you require that 95% ad-hoc Fairie Dust, because you continue to treat plasma like solids, liquids and gasses - in your conceptual models - an impossibility in any laboratory experiment ever done.

Please go away. I didn't start this thread just so you could hijack it with yet more of your idiotic EU nonsense.

 

[Radagast]

No, radiation intensity drops off as the square of the distance because the distance between particles becomes larger, allowing less photons to strike the same surface area.

Yes, but why as the square, and not linear or cubic? Because space is three-dimensional. As the picture you linked to illustrates, in fact.

 

[Radagast]

Still, the really interesting question is, what is this thing, which isn't just nothing, "made of?"

Another way of putting it, is: how is it that the Universe has (spatially) the mathematical structure of a (locally Euclidean) manifold with three dimensions?

If you answer: because it has the spacetime structure of relativity, then how does that work?