What is Space? (continued)

[ccwebb]

I originally asked this question about a year ago in the Classical Science section. (You can read it here). Since then, I have come across new (to me) information that I would like to get clarification on.

Pantheory's post was the last of the original thread:

By far the the simplest definition of space is that it is the volume the matter encumpases, or as you said: the distance between matter.

But this is not the present theoretical consensus model of space (unfortunately ) Although space is known to have energy within it, as in zero-point-energy, and hypothetical particles within it like dark matter, or theoretical particles like the Higg's and virtual particles, etc. But if present theory is valid then space, absent matter and energy, also can bend and warp like general relativity proposes, expand like the Big Bang model proposes, and accelerate its expansion like the dark energy hypothesis proposes, then space would need to have very complicated characteristics quite different from a volume of "nothingness."

I came across this article from Nasa that talked about "Einstein was right again".

 

http://science.nasa.gov/science-news/science-at-nasa/2011/04may_epic/

 

The results were announced about the Gravity Probe B (GP-B) mission proved that the spacetime around the earth is distorted, according to General Relativity. What is being distorted? Every example of space is given as a trampoline like example where mass puts a dimple into it. A spinning massive object drag space with it. Ok... then what is Space? How can it be bent or warped if it is simply the distance between matter?

[Strange]

 

What is being distorted?

 

Geometry. In other words, the way you measure the distance between points.

 

It is slightly subtler than that (you need to read up on GR and space-time curvature) but it is better than describing space as a trampoline, which is a truly terrible analogy.

 

[hoola]

I have heard this analogy that the planets warp or "dimples down" the space-time continuim. But there is no single "down" and there has to be at least a near infinite sets of "downs" at each point of the planet's surface, affecting space. This would lead to an even distortion of space, in the case of a non-rotating body, and with what I have heard of as "frame-dragging" if the body is rotating, with a gradient of max frame dragging at the equator, and a minimum at the poles. But, what is being distorted or "dragged" by the body? It seems to me that space is composed of the particle/antiparticle pairs and they are what is being distorted and/or dragged around. I see that gravity is information, the particles are information, and so they affect one another in the sense of changing their respective parameters, according to the relative strengths of the gravity force involved and to the degree that they can fundamentally react to one another. To me, it seems that the effects on space by gravity is due to mathematical changes of a given region, which are seen as a "distortion" in the case of the non-rotating body and "frame-dragged and distorted" in the case of a rotating body.....I agree that a single trampoline isn't a good analogy, unless you consider each point of a body having it's own trampoline intersecting it's surface at a right angle to the center or gravity, and those points creating a smooth surface surrounding the entire body....and that those points each describe the attendant distortion of space at that particular point in question... Then the analogy seems to make sense to me...edd.

[Coyote]

I have issues with describing spacetime as simply "geometry". One of my favourites analogies of the Universe is the raisin cake model, in which galaxies are the raisins that are moved apart as the cake grows. But, the raisins are moving apart because the cake (which is a substance) is growing. That's how I always pictured spacetime, as some "substance" carrying the galaxies apart. Otherwise, why are the galaxies moving apart?

[36grit]

A place for original thought to mature.

 

Just kidding but, not really.

If the electromagnetic scale is infinite in both directions then I'd speculate that; At some point it becomes so small that it appears non-relavant to our perspective of the universe but, that does not mean that it doesn't posses it's varying densities.

 

To suck everything out of a bottle is to dialate the surface a deeper grain.

[Cosmobrain]

 

Geometry. In other words, the way you measure the distance between points.

 

It is slightly subtler than that (you need to read up on GR and space-time curvature) but it is better than describing space as a trampoline, which is a truly terrible analogy.

 

this may be my favoriteimage ever