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Author Topic: Space is what exactly?  (Read 7154 times)

Offline Hadrian

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Space is what exactly?
« on: 10/04/2006 19:51:35 »
How do define space and is it the same everywhere throughout the universe?

How much is there out there?


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another_someone

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Re: Space is what exactly?
« Reply #1 on: 13/04/2006 05:51:21 »
I tried to leave this question to someone like Ian, who no doubt would have given a far more detailed and precise answer to the current thinking on this question, but since this has not obtained any response to date, I shall try and feed it with at least some vague ideas.

Firstly, as I understand it, there are very different views of space from the perspective of general relativity (which just views it as some sort of elastic medium that is distorted by the matter within it, but that creates a different view of that distortion depending upon the observer); the quantum physicists (who views it as an energy field in which matter is merely a manifestation of that energy); and the more natural philosophical view of space as merely a field of mathematical co-ordinates.

These are simplistic clichés, and no doubt other's are better able to fill in most of the details.

One thing one must ask is whether one is talking four dimensional space-time.

Another question is, if you are dealing with space-time, then is do you deal with points in space-time, or with curves in space-time.  What I mean is that a single point in space-time can only exist in a single point in time, and as such, unless it forms part of a curve through space-time, it cannot persist over time.  Even something that may look like a singularity in space, must form part of a curve (by curve, I include straight lines) through space-time, otherwise it would only exist for an infinitesimally small period of time, and so is unlikely to be perceptible.

Ofcourse, I suppose one could speculate that one dimensional space-time entities, even though they may not directly be perceptible, might have an influence upon objects that are curves through time, and that this might have the effect of creating random fluctuations that have no perceptible cause, possibly explaining the randomness in quantum physics.



George
« Last Edit: 13/04/2006 06:56:18 by another_someone »
 

Offline Hadrian

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Re: Space is what exactly?
« Reply #2 on: 14/04/2006 12:42:04 »
Its fantastic stuff George this thing we call space. There seem so much of it and yet it also keeps eluding us like far off hill. No matter how near we seem to get there always another question just over the horizon. Thanks for the information I enjoyed thinking about.  

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Offline Soul Surfer

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Re: Space is what exactly?
« Reply #3 on: 17/04/2006 09:44:57 »
I held off on this one until we got a few replies on it because the truth is no-one is really quite sure what space is.  A serious cosmologist (Julian Barbour I think)once described time as the thing that stops everything happening at once.  To extend this idea, space is something that stops everything in the same place.  

A lot of the wierd aspects of quantum mechanics suggest that space and time may both in some way be "illusions" because entanglement suggests that quantum changes happen without regard to space and time as we know it and if we look back to the big bang all particles must in some way be entangled.  Space to us appears dark and quiet but in the quantum mechanical world it appears to be full of energy and potential that just happens to balance itself out in the form of the appearence and dissapearence of all sorts of particles and antiparticles that only exist within the boundaries of uncertainty.

As mentioned above Einstein realised that the properties of light and gravity led to the linking of space to time in a continuous classical sense but there is no consensus about how this can be reconciled with the quantum mechanical universe and this is currently a major area of research in fundamental physics.

It is interesting to note that the dimensions of Plancks constant (the fundamental unit of quantum mechanics)are those of angular momentum and it is the conservation angular momentum  that prevents planets and electrons from collapsing onto the stars and nucleii that attract them and ensure that we have space in our universe.

Mathematical physicists like Roger Penrose have noted this and suggested that space is a "Spin matrix" in which there are a lot of interconnected vortices  a bit like a sort of stringy foam in four (or more)  dimensions.  The best image I can think of is it's a bit like a "scotchbrite" pan scourer with all the strings whirling round their axes and continually connecting and reconnecting with each other  the scale on which this happens is way smaller than even the nucleaus of an atom in fact a lot smaller than the ratio if the size of the nucleus of an atom to us!

This then brings us to string theory in which some groups of mathematical physicists thinking about the structure of the currently "fundamental" particles (these are leptons ( electrons and neutrinos )  and quarks (the things that make up protons and neutrons etc) which appear to be point like at even the highest energies (smallest scales) and the way that they interect and can change into each other have suggested that they may be string like at the smallest scales and have created several different sets of complex mathematical theories that can possibly explain this by coming at the problem from slightly different directions.  recently some of these have been unified and lead to things called superstring theory and supersymmetry.

Up to now I have tried hard to be impartial and as simple as possible but beyond this point I must declare an interest.  I feel that people are getting bogged down in detail and we are in need of some new simple ideas and approaches that may help them towards a solution.  I have been thinking about this and found an angle that I think is being forgotten.

The quantum mechanics of the hydrogen atom can be understood in simple classical terms if you recognise that matter has a wavelength associated with its momentum (that can be measured using simple classical experiments like electron diffraction) and consider that the electron matter waves are resonant in ther orbits around the atoms.

I feel that postulating the existence of a "stable" zero state black hole and considering how these might interact gravitationally in the same way as the classical/quantum hydrogen atom described above might give some insight.  Also considering the classical collpse of a rotating black hole inside its event horizon might also lead to some good ideas  (see "the view from a ring singularity" on these pages for more details of this)

The big problem with all of this is that the scales and energy levels expected for the quanutm gravity that will describe the crreation and destruction of space itself are so great is that they are way beyond any experiments that we are likely to be able to do and any proof must come from rather remore inferences.



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another_someone

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Re: Space is what exactly?
« Reply #4 on: 17/04/2006 15:42:08 »
Another question that is being hinted at, although not explicitly stated, is what is the relationship between space and matter.

Ian, much of the latter part of your post is as much about the nature of matter as it is about the nature of space.

The question is, is space an environment in which matter exists, or is matter merely an attribute of space, or space an attribute of matter?

Newtonian physics clearly separates the notion of time, space, and matter.

Your, totally reasonable, assertion that “space is something that stops everything in the same place” could be regarded as saying that space need not be anything but an attribute of matter (i.e. if all space is is a way of distinguishing bits of matter, rather like the attributes of spin and charge might distinguish between two types of matter, then in the absence of matter, there can be no separation, and so no space).  This would be consistent with the quantum “illusion” of space-time.

Incidentally, one question that has come to my mind a few times recently is whether a lot of the anomalies of “spooky action at a distance” could not be overcome if we disregarded the requirement that cause and effect can only move forward in time.  The other three dimensions of space-time are symmetric, yet we assume that time is not so.  Is this a consequence of the nature of time, or a consequence only of the limitation of our view of time (i.e. we cannot directly see into the future, so we assume – for very practical reasons – that the future cannot effect the past)?

I will try and give a crude analogy.

Suppose you place together three cylindrical rods balanced as a tripod, so that if any one rod is removed, the other two will fall down.  Clearly, the force transmitted between the rods at their tips is being transmitted all the way down the rods, and has an effect along the full length of the rod.

If a man is unable to see the rods in their totality, but can only take slices through the rods (rather like CAT scans take one 2 dimensional image after another, and then build them back up to a full 3 dimensional image).  If he is only able to take those slices starting at the bottom, and moving up the rods.  In each slice, he will see an elliptical (almost circular) cross section of each rod, and these ellipses will appear to be moving closer together with each slice, until they reach a point where they meat each other and then disappear.

Because he cannot see the effect each ellipse has on the other until he reaches the last slice, he can merely assume that they have no effect upon each other until they apparently collide and disappear, thus the only causal link he can perceive is an apparently linear motion, a collision, and a mutual annihilation.

The reverse of this, if the man were taking his measure from the top rather than the bottom, would have the apparent results that are similar to “spooky action at a distance”.



George
 

Offline Soul Surfer

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Re: Space is what exactly?
« Reply #5 on: 18/04/2006 10:16:46 »
There is some very interesting and thought provoking stuff there.

All the experts seem to say that the space and time we are aware of originated with the big bang and the big bang is not like an explosion expanding into pre existing space.  Similarly the currently observed expansion of our universe is not things flying apart after an explosion but the space between things getting bigger.  this allows the possibility of faster than light expansion between areas without braking the normal rules of relativity which seem to be very sensible.

I tend to agree with you that space, time and matter are inextricably linked.

Fundamental particle theorists seem to require a greater number of "dimensions" to describe our universe although they are undecided as to how many they need.  The recent rediscovery of heim theory which only requires a couple more is interesting.  I feel that like occam's razor one should not increase the number of dimensions unnecessarily.

My electronics and physics research background has taken me deep into communication theory this is not just about radio aand TV but explores fundamentally things that can and cannot be known given any system of physical laws one may choose to generate.  Some cosmologists are seeing that this could offer important insights into our universe.

Let me take the case of analysing an absolutly unknown "signal" for information.  this signal will consist of a set of "measurements" or observations. These are frequently in a time sequence but don't always have to be. One initially assumes that each measurement is totally independant of the other and represents an independant dimension of the total set.  The analysis tools then look for correlations between the measurements so that the information can be expressed using the smallest number of independant values to minimise the dimensionality of the data.  This then leads to finding the information contained within the signal.

I tend to feel that the only sensible solution to the multiverse is a set of universes that are born live and die just the way everething else in our universe is born, lives and dies in a continuous recycling process and the sooner we accept this the better we will be.  That is why I am interested in the potential entropy reversing properties of the collapse of rotating black holes and wish that more and better minds than mine would take it more seriously.  OK if someone comes up with a better idea I am happy to hear it.

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another_someone

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Re: Space is what exactly?
« Reply #6 on: 18/04/2006 18:13:29 »
quote:
Originally posted by Soul Surfer
I tend to feel that the only sensible solution to the multiverse is a set of universes that are born live and die just the way everething else in our universe is born, lives and dies in a continuous recycling process and the sooner we accept this the better we will be.



If our universe did have a birth (and I am not sure that the big bang has been conclusively demonstrated, although it is the preferred theory), then it does make more sense to assume it will die.

At very least, if one believes that everything has a cause (which may or may not be the case, but a breach of causality would seem to be unscientific), then it follows that anything that is created must consume some resource of some kind.  It then follows that, unless there is an infinite supply of the said resource, that either there must be a finite number of creation events, or at some time the resources consumed must be returned to the pool of available resource to allow further creation events in the future.  The only way one can imagine the return of those resources would be the destruction of that which was created.

There are a number of assumptions in the above, but I don't think the assumptions are unreasonable.





George
 

Offline Hadrian

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Re: Space is what exactly?
« Reply #7 on: 19/04/2006 15:02:55 »
If something is occupying space dose it displace it or incorporate it.



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another_someone

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Re: Space is what exactly?
« Reply #8 on: 20/04/2006 01:07:11 »
quote:
Originally posted by Hadrian
If something is occupying space dose it displace it or incorporate it.



If space and matter one one and the same, then it does neither.



George
 

Offline ukmicky

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Re: Space is what exactly?
« Reply #9 on: 20/04/2006 01:12:16 »
quote:
Originally posted by another_someone

quote:
Originally posted by Hadrian
If something is occupying space dose it displace it or incorporate it.



If space and matter one one and the same, then it does neither.



George


but how can space and matter be one and the same , matter bends space but space dosent bend matter:)

Michael
 

another_someone

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Re: Space is what exactly?
« Reply #10 on: 20/04/2006 01:27:23 »
quote:
Originally posted by ukmicky
but how can space and matter be one and the same , matter bends space but space dosent bend matter:)

Michael



But what does it mean to say that space is bent? :)

(and, no, I am not trying to link up with the thread on homosexuality :))



George
« Last Edit: 20/04/2006 01:29:48 by another_someone »
 

Offline ukmicky

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Re: Space is what exactly?
« Reply #11 on: 20/04/2006 02:13:16 »
quote:
Originally posted by Hadrian

If something is occupying space dose it displace it or incorporate it.



What you do speaks so loudly that I cannot hear what you say.



Could space be made from tiny particles which are so so small that they can sit in between the particle's which make up matter allowing space to be incorporated in to matter. Just like how an amount of salt can be poured into  a glass of water without increasing the level of water as the salt molecules are small enough to fill the gaps between the water molecules.


Ok this part may not make sense its just that your question got me thinking, WHICH IS  DEADLY :)

If mass displaces space then you also have to ask the question if displaced space can occupy the same space which is already occupied by space,do you follow :) and if the displaced space can't occupy space which is already occupied by space what happens to the displaced space. Does it gather around the item displacing it in compressed waves of space. but then even a compressed wave made from gathered space would occupy space which is already occupied by space. so maybe the gathered compressed spacial wave then breaks through into another dimension as it has no where in our dimensions to go and this other dimension is occupied by gravity which then bleeds out into our dimension pulling things towards it.

AS YOU CAN PROBABLY TELL I'M NOT A SCIENTIST ,BUT I AM NAKED:D:D



Michael
« Last Edit: 20/04/2006 02:26:51 by ukmicky »
 

another_someone

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Re: Space is what exactly?
« Reply #12 on: 20/04/2006 02:41:50 »
quote:
Originally posted by ukmicky
Could space be made from tiny particles which are so so small that they can sit in between the particle's which make up matter allowing space to be incorporated in to matter. Just like how an amount of salt can be poured into  a glass of water without increasing the level of water as the salt molecules are small enough to fill the gaps between the water molecules.



Sorry, now I am confused.

You seem to be saying that space is made up of particles that sit in the space between mass – but it does not explain what the space between the mass is, except that it contains tiny particles?



George
 

Offline ukmicky

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Re: Space is what exactly?
« Reply #13 on: 20/04/2006 02:47:01 »
Don't know I'm just asking if space could be made out of tiny particles allowing it to flow through and reside within matter, which would mean that matter would not displace it as ask by hadrian:) because if matter does displace space then somehow you would have to decipher and understand what i wrote further on and answer it:D

Michael
« Last Edit: 20/04/2006 02:53:13 by ukmicky »
 

another_someone

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Re: Space is what exactly?
« Reply #14 on: 20/04/2006 03:08:35 »
quote:
Originally posted by ukmicky

Don't know I'm just asking if space could be made out of tiny particles allowing it to flow through and reside within matter, which would mean that matter would not displace it as ask by hadrian:) because if matter does displace space then somehow you would have to decipher and understand what i wrote further on and answer it:D

Michael



Apart from the lack of answer about what is between the particles, and what is between the mass, it also still assumes that they are distinctly different things.

Let me give you an example where two things can exist that are one and the same, neither displacing the other because they are both the same.

Think of supercooled water.  Spontaneously, you could have a crystal of ice growing within that water.  The ice does not displace the water, because they are the same thing, just in a different state.

Ofcourse, there is the other possibility that was discussed, that space does not exist at all, but is merely an illusion.

We have said that space (and time) is a measure (and may be no more than a measure) that simply prohibits two things from occupying the same position at the same time.  In that, one may compare it the the Pauli exclusion principle for the state of Fermions.  If one were to say that two electrons cannot occupy the same energy state, would one ask what fills the gap between those energy states?

PS. Not being a scientist is no excuse, I'm not a scientist either (but I'm not naked right now either) :)



George
« Last Edit: 20/04/2006 03:12:16 by another_someone »
 

Offline ukmicky

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Re: Space is what exactly?
« Reply #15 on: 20/04/2006 03:54:36 »
quote:

Think of supercooled water.  Spontaneously, you could have a crystal of ice growing within that water.  The ice does not displace the water, because they are the same thing, just in a different state.

i could be wrong here but for one form of matter to be in two state's like in your water and ice example wouldn't one of the state's have to contain more energy than the other and because they were coexisting together  wouldn't there then  be a transference of energy from one to the other eventually causing the two states to become  one

Michael
« Last Edit: 20/04/2006 04:07:15 by ukmicky »
 

another_someone

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Re: Space is what exactly?
« Reply #16 on: 20/04/2006 04:02:14 »
quote:
Originally posted by ukmicky

quote:

Think of supercooled water.  Spontaneously, you could have a crystal of ice growing within that water.  The ice does not displace the water, because they are the same thing, just in a different state.

i could be wrong here but for one form of matter to be in two state's wouldn't  one of the state's have to contain more energy than the other and because they were coexisting together  wouldn't there then  be a transference of energy from one to the other eventually causing the two states to become  one




In the most general sense, all that energy is is a measure of the degree of preference that a system has for one state over another; so in that sense, in order that a system should be able to change from one state to another, there must be some form of energy difference between the states.

It does not necessarily follow that because one state is preferred to the other, then all of it will change from one state to the other.

Take the example of the supercooled water again.

If the supercooled water is in an isolated system, where no heat is allowed to enter or leave the system; then as some of the water condenses into ice, so it was create heat, and in doing so it will warm up the surrounding water, and thus come to a point of equilibrium, where no more water can condense into ice, but none of the existing ice can convert back to water because that would be an endothermic process for which there was insufficient heat within the system.



George
« Last Edit: 20/04/2006 05:57:06 by another_someone »
 

Offline Soul Surfer

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Re: Space is what exactly?
« Reply #17 on: 20/04/2006 13:43:35 »
since I was a kid I have always tended to think that space is the fundamental thing and it would turn out that matter is just bits of screwed up space.  The way that nuclear reactions aloow one set of particles interacting to transmute into another set of particles tend to indicate that that they are all the same at the deepest level.

Think of cellular automata like the "life" computer programme or the stuff talked about by Stephen wolfram in "a new kind of science" particles and waves are just special distortions and transmutations of the elements that make up space.

Recenr loop quantum gravity ideas (see this week's new scientist)  are very similar.

There they suggest that space is a bit like a multidimensional fabric built up out of little loops of space all interconnected and even go on to suggest that as a black hole contracts towards a singularity all these loops get streightened out and then re-emerge as another dimension and end the singularity  (now where have I heard something like that before ! ;-)

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Offline Sandwalker

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Re: Space is what exactly?
« Reply #18 on: 27/04/2006 20:06:19 »
Perhaps matter is just screwed up multi-dimensional spacetime.

Perhaps the universe is a singularity, its maybe perception that gives it dimensions, change and time.

What we see is not reality, it is what we perceive as reality, its an abstraction in our heads.

For example colour is a vibration in the em spectrum the colour can be said to be an mental abstraction of the em vibration.

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Offline Hadrian

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Re: Space is what exactly?
« Reply #19 on: 27/04/2006 20:19:45 »


Is everything that is not space is in space?

 



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Offline steveoifer

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Space is what exactly?
« Reply #20 on: 13/02/2011 18:46:30 »

Space exists, because we make it exist.

Without a viewer, does anything truly exist?

If God created everything and if we create that which we perceive, then our projected God is actually us!

 

Offline yor_on

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Re: Space is what exactly?
« Reply #21 on: 16/02/2011 05:23:19 »

Suppose you place together three cylindrical rods balanced as a tripod, so that if any one rod is removed, the other two will fall down.  Clearly, the force transmitted between the rods at their tips is being transmitted all the way down the rods, and has an effect along the full length of the rod.

If a man is unable to see the rods in their totality, but can only take slices through the rods (rather like CAT scans take one 2 dimensional image after another, and then build them back up to a full 3 dimensional image).  If he is only able to take those slices starting at the bottom, and moving up the rods.  In each slice, he will see an elliptical (almost circular) cross section of each rod, and these ellipses will appear to be moving closer together with each slice, until they reach a point where they meat each other and then disappear.

Because he cannot see the effect each ellipse has on the other until he reaches the last slice, he can merely assume that they have no effect upon each other until they apparently collide and disappear, thus the only causal link he can perceive is an apparently linear motion, a collision, and a mutual annihilation.

The reverse of this, if the man were taking his measure from the top rather than the bottom, would have the apparent results that are similar to “spooky action at a distance”.



What sweet thinking.

We see relations and create statements, building a causality chain where each part hopefully leads to another, but where we only can use what we know. That's how it seems to me too, but what would that make time? If we use the analogy of 'spooky action', beginning at the top of the tripod going down, and then acknowledge that a different test done simultaneously present you with the opposite, going up? If we assume that time present us with a reversibility, as it seems, we should be able to confirm this idea in a experiment. What I'm not that keen on myself is those 'hidden dimensions'. Not because they're impossible in themselves, but they seem so impossible to confirm and experiment with? But that analogy was really nice.
 

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Re: Space is what exactly?
« Reply #21 on: 16/02/2011 05:23:19 »

 

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