Where Does Space End? It Must End Somewhere!

[Strange]

It does and we now have prove. Dark matter is expanding our universe.

 

Dark matter is nothing to do with the expansion of the universe.

 

Thus meaning that the universe as a "wall" to say.

 

 

There is no "wall".

[Zjcross]

Some say that space is never ending. If so what does it expand into and what is that? Another dimension maybe? My theory is that space is a sphere with currents similar to those of the oceans and therefore, keep us in constant motion. Giving the pretense that we are moving farther away from the location of the Big Bang.

[Strange]

Some say that space is never ending. If so what does it expand into and what is that?

 

It doesn't expand into anything. Your mental model of space like a sphere is completely unrealistic. What happens is that the distance between points in space increases.

 

 

Giving the pretense that we are moving farther away from the location of the Big Bang.

 

What we observe is that everything is moving away from everything else (not from some central point). This makes sense because the "location of the big bang" is everywhere.

 

One way to visualise this is to wind the clock back. Over time galaxies would get closer and closer together. Ultimately everything would be in the same place. That "place" is where the big bang happened. As space expands, that place expands and everything is still in that place.

 

Also, the big bang didn't "happen"; it is still happening. It is a model of the evolution of the universe from an early hot, dense state.

[Endy0816]

I'm actually trying to make a visualizer for this. Superclusters plotted along the Time axis.

 

Not hard to make it so you can slide back and forth and see how the perspective of someone in one of those superclusters is impacted.

[Strange]

I'm actually trying to make a visualizer for this. Superclusters plotted along the Time axis.

 

Sounds cool.

[Thorham]

What I want to know is what space is physically?

[Mordred]

What I want to know is what space is physically?

Volume if you remove all standard model particles both real and virtual. You will simply have volume

Edited June 6, 2016 by Mordred

[Strange]

Space is what rulers measure.

[Thorham]

Volume if you remove all standard model particles both real and virtual. You will simply have volume

 

Volume is a quantity, not a 'stuff'. I asked what space is physically. Is it some sort of medium that consists of something, or absolute nothingness?

 

 

 

Space is what rulers measure.

 

LOL

Edited June 6, 2016 by Thorham

[Strange]

 

Volume is a quantity, not a 'stuff'. I asked what space is physically. Is it some sort of medium that consists of something, or absolute nothingness?

 

 

Space is a quantity. It is the distance between things. Typically defined with three orthogonal coordinates.

 

LOL

 

 

That wasn't a joke. Apart from being a reference to the common definition that "time is what clocks measure".

 

We have instruments that measure space (rulers) and instruments that measure time (clocks). They are just the dimensions of space-time.

And it is those measurements that increase when space "expands" (a dubious and apparently confusing metaphor).

[dimreepr]

Space is what rulers measure.

 

 

Space ends here, unless the Rulers decide otherwise...

[Airbrush]

Interstellar, or intergalactic, or intersupercluster space is probably not absolutely nothing. It is something that only seems like nothing.

[Thorham]

Space is a quantity. It is the distance between things. Typically defined with three orthogonal coordinates.

 

It's not that simple, because of space curvature. It seems to go a little farther than just the distance between things. It leads to the question whether space is something that physically gets curved by mass, or that it's just nothingness.

 

Note that I'm not questioning the current gravitational model here, because that undoubtedly works very well.

[Robittybob1]

 

It's not that simple, because of space curvature. It seems to go a little farther than just the distance between things. It leads to the question whether space is something that physically gets curved by mass, or that it's just nothingness.

 

Note that I'm not questioning the current gravitational model here, because that undoubtedly works very well.

Space time and space are different.

[Velocity_Boy]

Well according to many Cosmologists including Einstein, TIME is a constituent of Space. That is to say, a part of. And while different yes, only in the way that, say, the color blue is different that another color in the Spectrum but still a part of it.

 

They call this the Space/Time Continuum, or STC.

 

And its been proven that lights gets curved or altered by mass and the gravity that mass exudes. But space? Hmm...not so much I don't think.

 

I always liked to think of Time maybe being to Space what those colorful little swatches of lights on a soap bubble are to the bubble. That bubble being Space.

 

But you can question the Gravitational model all you want. Why not? we still don't know how it works! Or what the medium is for its force. Oh, we call them Gravitons but that is only a sort of place-holder of a word. We've no idea that a Graviton consists of. Much like the mass-carrying particle we called the Higgs Boson, before we discovered it a few years ago at the CERN LHC.

 

I think space CAN be infinite. It's just that our homo sapien minds are incapable of grasping the notion of infinity. We have no experience with it, anbd certainly noway of observing or testing it. We can only use picture models and metaphors. Analogies, so staggering is Infinity in its totality. Like we do with those vast cosmological distances. And numbers. As in the hundreds of billions of galaxies with hundreds of billions of stars in each one, likening them to all the total grains of sand on all the world's beaches.

 

Or how to show the vast emptiness of an atom, we picture the nucleus as a football sitting at the 50 yard line, and the distance of the attendant electrons are flying around at light-speed outside of the stadium, and are the sizes or grains of sand if the nucleus is the football.

 

I digest. Er, digress.

 

My personal take is Space IS finite, and this current Big Bang of a mere (!) 13.8 BYA is only the latest in a series of BB's and BC's, (big crunches.) Part of an infinite cycle. (damn..there's that word infinite again!) LOL.

[Mordred]

 

It's not that simple, because of space curvature. It seems to go a little farther than just the distance between things. It leads to the question whether space is something that physically gets curved by mass, or that it's just nothingness.

 

Note that I'm not questioning the current gravitational model here, because that undoubtedly works very well.

The curvature is the the measure of influence due to mass. It doesn't act upon space itself as that's just a geometric volume. The influence acts upon the standard model particles that reside in space.

 

A common and practical way to express or model this curvature is to assume a field of test particles residing in every point in space. The strength of influence upon those test particles has a curved relation the further you get from a source of mass.

 

Mathematically we express this as a curved geometry change. The density of test particles increases as you approach mass. Each coordinate being represented by a test particle.

 

Now this still works for geodesic relations as the mass density follows the same relation. However this mass density isn't space itself but the standard model particles.

 

A way to learn this is the principle of least action which involves Langrene densities.

 

At no time did GR states that spacetime has substance. That would entail an eather which has been proven wrong. The main tests involve Eather dragging.

 

The above relates to how fields are described. For example a gravitational field is a field like of test particles.

https://en.m.wikipedia.org/wiki/Test_particle

Edited June 7, 2016 by Mordred

[Strange]

 

It's not that simple, because of space curvature. It seems to go a little farther than just the distance between things. It leads to the question whether space is something that physically gets curved by mass, or that it's just nothingness.

 

 

The distance between things can become curved in the presence of mass (or energy). This means, rather like measuring distances on Earth, the distance (or time) between events can depend on the path you take through spacetime (e.g. how fast you go).

 

It is the geometry that changes, rather than any physical "stuff".

[Thorham]

Thanks for explaining

 

At no time did GR states that spacetime has substance. That would entail an eather which has been proven wrong. The main tests involve Eather dragging.

 

They sure make it seem as though it does in documentaries. They really need to stop doing that.

That clears that question up, then.

[Strange]

Thanks for explaining

 

 

They sure make it seem as though it does in documentaries. They really need to stop doing that.

 

That clears that question up, then.

 

It is rather annoying that popular science documentaries never say that they are giving a simplified analogy, rather than the "real science". People then take the illustrations and metaphors as being what the science really says and end up confused.

 

I suppose it is better than no science communication. But I do think they could do better.

[Airbrush]

My personal take is Space IS finite, and this current Big Bang of a mere (!) 13.8 BYA is only the latest in a series of BB's and BC's, (big crunches.) Part of an infinite cycle. (damn..there's that word infinite again!) LOL.

Your "personal take" is very similar to mine, and I've never heard anyone discuss it. "Space-time" seems to me to have originated at the big bang. Before the big bang was something similar to space-time, but time did not exist yet. Before the big bang we had "space", after the big bang we have "space-time".

 

I also have issues with the word "infinite". It seems like a hurdle for the big bang to occur at all, and for the big bang to result in an infinite universe is a second hurdle. It still seems to me that the big bang, or our universe, is just another finite structure above galaxy superclusters. The multiverse would be the set of all big bangs extending out to infinity. But then maybe the multiverse is only the next higher finite structure, beyond which is unknowable.

Edited June 7, 2016 by Airbrush

[Strange]

I also have issues with the word "infinite". It seems like a hurdle for the big bang to occur at all, and for the big bang to result in an infinite universe is a second hurdle.

 

The big bang was not an event. It is a model that describes the (continuing) evolution of the universe from an early hot dense state.

 

 

The multiverse would be the set of all big bangs extending out to infinity.

 

There are a number of variants of the big bang model that include this sort of idea (eternal inflation, for example).

[Strange]

This is a good, non-mathematical, article explaining why the "expanding space" analogy is not very meaningful and why space doesn't need to be "made of something":

http://arxiv.org/abs/1605.08634

[Thorham]

The notion that everything must end somewhere is very human. When looking at the universe, one much look beyond such notions.

 

Seems to me that space is infinite and existence is eternal.

[Mordred]

One might think that considering the vastness of our universe. However we haven't discounted the possibility of a finite universe.

[Thorham]

One might think that considering the vastness of our universe.

Not really.