Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: carpaticus on 03/09/2009 12:47:54
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I'd like to know if anybody out there has a clear idea about what space really is:
1. Is it something created by the original Big Bang energy and expanding with it?
2. Is it something infinite already existing before the Big Bang and in which matter/energy evolves?
3. Is it something made of some particular quanta still undiscovered?
Is there any theory about my 3rd point? IMO descovering space quanta will automatically lead to the unification of relativity and quantum theory.
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where is the proof that space expands?
(i'm not talking about the expansion of the universe which could be the expansion of matter/energy in an already existing space, presumably bigger than the universe itself)!
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It needs to be space that expands so that it can drag light along with it as it expands. Otherwise there is the problem that the universe is larger than it could possibly become within the speed of light constraints.
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yeah but if we assume that space is infinite and preexisting the big bang, that does not contradict the experimental evidence: what we see is the light horizon of the universe, but not of space itself.
the big bang could have occured in a preexisting and infinite space and light can travel thru it as well as matter expands within it.
is there any evidence that space was created by the big-bang?
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I know of no evidence that space was created at all. We can take away every thing we know about from space, and we still have space. It still has the properties of magnetic permeability and electric permittivity.
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What is space?
That is a very good question.
Despite the fact that it clearly exists, it doesn't appear to be made out of anything: it doesn't seem to be a form of energy or matter, at least in any form we know about.
In its most abstract sense we can describe space as that which allows things to occupy different locations, whether it be a single thing that changes its location, or several things occupying several locations. As such then, it permits change and complexity, for if nothing can change then the universe would be static, and without complexity the universe would consist of just a single item.
Another abstract description would be to liken it to a measuring scale or an axis. However, when we use a scale or an axis to measure or locate something it is the 'something' we are measuring or locating that is the important thing, not the measure or axis that we use to do so. For example, if someone asked you for a three metre length of string you might use a tape-measure to measure off three metres of string from a ball and give it to them but it would not be adequate for you to simply mark out a length of three metres in the thin air in front of them.
The shape of space, and time too, because you really need to think of both as a single space-time concept, appears to be intimately linked to gravity. We generally think of gravity as a force, from Newton's description of it, but in relativity it is interpreted as a distortion of space-time. In both descriptions though, it is due to the presence of matter, so if we go back to our bit of string it turns out that the tape-measure we used to measure off the length of string is actually affected by the presence of the string we were measuring. Space-time then, is a bit like a tape-measure that has been made out of rubber.
Perhaps then, we shouldn't view space-time and matter as different things but instead treat space-time as a property of matter, and even energy, as mass and energy may be converted. This makes sense in terms of permitting change for if something is to change its location it needs somewhere else to go to. Thus, just the mere existence of an 'item' or 'object' of matter or energy results in a region of space-time around that item/object.
Furthermore, if the amount of change is limited to a finite amount, such as its rate of spatial movement being limited to the speed of light, the size of the region of space around the object need only be finite in extent, as it would only need to be big enough to allow the maximum amount of change.
Now, if we assume that objects can only interact when they share the same region of space-time i.e. they exist in a common 'universe' environment, then finite sized regions of space-time around multiple objects would result in distantly located objects being isolated from each other and unable to interact whilst closely located objects, with intersecting regions of space-time, would be able to do so. Conversely, if an object's region of space-time were infinite in extent it would seem that all objects would share a common 'universe' environment and thus be able to interact, even if distant from each other, and unless one posits some sort of probability gradient along the radius of the infinite region, with equal probability to local objects.
Heh [;D] funnily enough, in the above model, quantum entanglement suggests action at a distance i.e. infinite radius, but with no probability gradient, as there's no probability, afaik, that the distant entangled particle won't resolve when the first does. That is, afaik, the resolution of the distant quantum entangled particle is guaranteed when the first is resolved.
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I wish that we really knew what it is.
I do not think that it is fundamental and pre-existing but is a fundamental property of our universe and coupled with time as a totally relative thing. that is space exists because it takes time to cross it and time exists because space defines how we see what happens but there is no fundamental size of space.
Quantum theory with its entanglement and tunneling properties show that simultaneously with being very large it is also very small. All modern theories of everything include the existence of more dimensions than the four that we currently experience.
Dark matter and energy also probably has something to do with it I tend to visualise there being "particles" of space which themselves have energy and occasionally interact to create more particles of space.
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The question could be asked: Is space "Nothingness"? Quite simply, the answer is No. Space/Time changes shape when exposed to the presence of Gravity. If then, it can change shape, it is composed of something. What that something consists of, at this juncture is not completely understood..................Ethos
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All modern theories of everything include the existence of more dimensions than the four that we currently experience.
Maybe you should qualify that a bit. There are several theories of everything (http://photontheory.com/pte.html) that do not require ideas more complex than those that were around at the turn of the 20th century.
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The question could be asked: Is space "Nothingness"? Quite simply, the answer is No. Space/Time changes shape when exposed to the presence of Gravity.
I think this is an assumption we make to accommodate GR. The assumption is generally accepted by the scientific community, but that doesn't make it the reality.
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thanx LeeE for trying to make it clearer! nice explanation
of course it's one of the toughest things to explain and the mystery goes on, as we still haven't found any gravitational wave that could probably make things clearer!
but yeah, as stated earlier by another poster, the fact that space-time is deformed by mass (thus creating the gravitational effect) it would be more sensible probably to say that it is made of something!
and possibly the extreme compression of this space-time (for whatever reason) could have generate the original burst of energy of the Big-Bang that materialised (slightly) later into matter as we know it!
and the so-called "dark energy zones" in space could be zones with lower densities of "space particles" that have an accelerating effect on galaxies already going far-away from each other
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we still haven't found any gravitational wave that could probably make things clearer!
To digress a little, although no coherent gravitational waves have been detected receivers are plagued with noise much as Karl Guthe Jansky's horn antenna picked up the CMBR
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The question could be asked: Is space "Nothingness"? Quite simply, the answer is No. Space/Time changes shape when exposed to the presence of Gravity.
I think this is an assumption we make to accommodate GR. The assumption is generally accepted by the scientific community, but that doesn't make it the reality.
Very true my friend. So let's preform a thought experiment. If space/time is really nothingness, then what could explain the curvature of light around a local gravitational source? Could the electromagnetic effect of the matter cause this? Or, are we only seeing an illusion of sorts? I have always been left a little unfulfilled with the GR explanation myself anyway. My gut tells me that space/time is only an empty volume where change can take place but GR explains it as a mysterious something we, as yet, can't define. I would truly love for another explanation, with proof, to come forth.
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I suspect that space is really just nothingness. We can think of it as space-time but that does not fill any need in the way I think of space and time. As far as light passing close to a massive object, the light is attracted by gravity. The slight bend due to gravity produces positive feed-back that bends the light more in the same direction. Observation shows that the amount of bending caused by the feedback is equal to that caused by gravity.
I don't view gravity as warped space-time. Warped space-time does not work in a universe where the final irreducible constituent of all physical reality is the electromagnetic field. In that kind of universe gravity has the same source as quantum phenomena. It comes from the saturation property of photons. (http://photontheory.com/TheEvidence.html) Robert Kemp explains this property. (http://photontheory.com/Kemp/Kemp.html) However, he does not ascribe gravity or quantum phenomena to it.