Where Does Space End? It Must End Somewhere!

[Realitycheck]

No shortcuts. It still takes many billions of miles to get back to where you started.

[DrRocket]

You mean something more like closed, ie.compact and without boundaries.

 

Spherical suggest you mean a space-time whose isometry group contains SO(3) as a subgroup.

 

 

It sounds to me as though he means a flat 3-torus. That is one posibility, though not technically globally isotropic.

[Realitycheck]

Well, maybe not. I finally got around to reading up on topology and that's kind of what I already believed in, sort of, I think.

[pantheory]

Wow, this is a long, old thread but a very good question. Where does space end? I think it comes down to the definition of space and there is no consensus concerning a definition. I agree with those Big Bang theorists who assert that both time and space were created from the beginning of the universe, and there is no such thing as before that. In the same way the meaning of space could be defined as the volume that matter occupies concerning its volume, or two dimensional space could be defined as the distances between matter. This I think explains the question. Space extends as far as matter extends. As Decarte proposed, space is an extension of matter.

 

Beyond this meaning I believe philosophy begins. Such a question would be: what would be the meaning of space outside the bounds of all matter and field, or similarly what would be the meaning of time if nothing existed that could change?

[Marqq]

There's no way at all for space to end. The only evidence suggesting such is that what we can see appears to have an edge, beyond which nothing can be seen. If you consider the equivalent systems in scale (atoms, solar systems, galaxies..), you'll see clearly that such systems are all VERY far apart... Of all that we can perceive, what we're calling our 'universe' is really just the next step up; let's call it our 'galactic cluster'. It's a large expanse in which matter became initialized, but certainly not all there is to existence. Our big bang is just one of many sensible occurrences that induce the creation of matter. The only reason we can see nothing beyond that 'wall' is the distance, along with the state of the surrounding galactic clusters. I must point out here that I'm only a lay theorist, but guess what I've got: A Theory!

 

Earlier in this thread, there was debate over the divisibility of quarks; to this I ask: remember that stuff about all matter (etc.) being energy waves?; How is a wave expressed, if not on smaller particles?... I'd suggest that all particles exist on some base particle, I call it the 'Tween'. I won't go into depth here, but I believe these 'tweens' are essentially the fabric of the universe, onto which everything we know is embossed, given a specific number of tweens to make it up, a system of frequencies, and as a function of the first, a range of possible energy levels (likely non-quantifiable). Essentially, there IS (in my opinion) an a-tom (uncuttable) particle, I just think it's a couple levels below the quark, and it's the ultimate, from which all things are made. The reason I call this the 'Tween' is that it would be what exists between all other particles, as well, filling in the void/vacuum. I believe that any true vacuum would be the greatest imbalance ever to exist in nature, and from the energy of even the smallest volume of one to be the cause of what's called a 'big bang'. Furthermore, I believe the only way to form even such a miniscule true vacuum, is for the vast fabric of tweens to be pulled in 4 directions (toward the corners of a tetrahedron) by other collapsing(or even growing) galactic clusters (or the popular term, universes--but this goes against the meaning of the word).

 

OK, a couple notes on tweens:

1. They can overlap, thus filling in all space between their centers while themselves being round (presumably).

2. They're the cause of gravity. Latent energy from the disruption of their area (caused by the big bang, matter existing, and other such offenses) brings together tweens into what could be called 'graviton particles', though I think science has named them differently. Such particles are known to phase into and out of perceived existence, and repel one another due to equivalent frequency very strongly. When in proximity of normal matter, or tween constructs of higher energy levels, they appear to cease to exist, having had their energy (including movement energy) absorbed by the higher-threshold system, and ebb through and around space as normal tweens thereafter, until becoming energized again. Since these 'gravitons' are so easily absorbed by massive objects, and so repelled by one another, they form a never-ending flow towards massive objects, the end result of which is what we call gravity. (Does that follow? I think it does... Please feel free to point out any logical flaws there.)

 

I've given a great deal of though to these theories, especially the existence of Tweens, so if you have any irrefutable corrections or counterarguments, please post them! I'm new here, but I bookmarked it, so I'll be checking back!

[Airbrush]

Welcome aboard Marqq. Your "tweens" sound like strings and your theory sounds a little like string theory. How does your theory differ from string theory?

[michel123456]

Interesting how the Democritus spirit still lives on.

 

Interesting also that we are ready to consider an infinitely large Universe, but we are totally incapable to accept an infinitely small.

We all search in the very small in order to find a presumed "elementary building block". Presumed because we get vertigo under the idea there could be no such a thing, and that infinite could extend in the small dimension as well.

[Marqq]

Welcome aboard Marqq. Your "tweens" sound like strings and your theory sounds a little like string theory. How does your theory differ from string theory?

 

Well, to start with, it's a lot less complicated. I realize that also means my idea is much less developed, but I believe that even upon development, it would end up far less complicated (and thus, in my opinion, more likely). I don't see any need for more than 3 dimensions (as is apparently required by the frightening mathematics involved with string theory), and I can't bring myself to accept that anything actually exists in 1, 2 or 4+ dimensions.

 

The strings in string theory are said to be lines which, as far as I know, have no thickness, and occupy space only through exceptionally indescribable modes of vibration. These strings apparently have their own spacial dimensions, bending left and right forward and back, combining and dividing, all while only being singular universal building blocks. Even my VERY limited understanding of it seems overly complicated and fantastical to me. I wonder how a string, as described, can bend without joints? A singular point, however, needs not bend or stretch, and forms the most basic of building blocks (and, once again, the most likely). Such singular points are the centers of my tweens. Existing as fields of indeterminate size, tweens are (to me) the obvious immutable building blocks of existence. If strings exist, I'd posit that they're actually the borders where tween edges overlap...that would give them reason to bend, loop, join and divide; it would also explain their lack of thickness--they're just the intersection of planes.

 

In essence, the difference in theories is only a disagreement of building blocks. I haven't developed the idea enough for any more comparison, but I only understand very little about string theory... Tween theory was originally only my way of alternately explaining the two-slit experiment...I mean really, a single electron going left, right, down the middle and nowhere all at once? Nah...it's just diffused due to speed, its energy and frequency spread over an area until reconstituted by an imbalance...

[Ophiolite]

Marqq, you seem to have based your ideas on incredulity at alternative explanations. Do you think that is wise?

[pantheory]

Margg,

 

"Well, to start with, it's a lot less complicated. I realize that also means my idea is much less developed, but I believe that even upon development, it would end up far less complicated (and thus, in my opinion, more likely). I don't see any need for more than 3 dimensions (as is apparently required by the frightening mathematics involved with string theory), and I can't bring myself to accept that anything actually exists in 1, 2 or 4+ dimensions.

 

The strings in string theory are said to be lines which, as far as I know, have no thickness, and occupy space only through exceptionally indescribable modes of vibration. These strings apparently have their own spacial dimensions, bending left and right forward and back, combining and dividing, all while only being singular universal building blocks. Even my VERY limited understanding of it seems overly complicated and fantastical to me. I wonder how a string, as described, can bend without joints?......."

 

(your quote above)

 

My own theory concerning the structure of matter is similar to yours. String-like strands of elementary particles (in my case) in 3 dimensions which form loops and spin as fermions. Nothing complicated also, except the math and even that is much less complicated than the 11 or more dimensions of conventional string theory. The width dimension of zero for conventional string theory is also meaningless I think. The math of string theory requires that the width of zero is used but actually the width could theoretically be many times smaller than a plank length which is pretty small. This would enable the use of zero in the calcs. Use any search engine on my screen name pantheory and you will see my theories.

 

As to how far space extends, I believe would be easy for most people to understand the answer once a "better explanation" of space is explained. To explain this definition and understanding of space, is that space only extends to the extent that matter exists, within the same confines, and not beyond. If one defines space to include volumes outside the confines of matter in the universe (considering there is only one universe), what would be the value or meaning of such a definition that was unrelated to matter? seemingly None! It would be a meaningless volume and concept outside the confines of matter and field, just like a definition or description of time that would include time separate from the physical existence of matter and field. An example of such a sterile definition of time might include intervals during which nothing at all could change or happen except for hypothetical time changes within the interval. The key words that I think should define time is accordingly "an interval of change" in physical reality and the key words that define space is "an interval of extension," within a physical reality. Such a space or time interval requires at least two reference points. Both time and space also require a standard for comparison to enable a numerically value to them. Such length standards for distances which we presently use are the meter, the light year, cubic parsecs, etc. (for space), and for time the second, the year, etc. Although we use the phrases of "a point in time" or "a point in space," a single point cannot explain either word. Both time and space accordingly require matter at two or more observable or theorized points at their extremities to give meanings to all facets of concerning explanations of an interval including a numerical value, or a useful identification concerning what particular interval you are referring to.

 

For the same reasons time or space as a continuum in all possible directions which would be too broad of a definition of "present reality" since it would include infinity vectors (in one or more directions), which are non-intervals which accordingly could confuse understandings of space or time. These vectors might only point the direction toward possible future extensions of space or the probable single vector extension of time.

Edited June 18, 2011 by pantheory

[csmyth3025]

...As to how far space extends, I believe is easy for most people to understand the true answer once it is explained to them. To explain the correct definition, I believe, is that space exists to the extent that matter exists, within the same confines, and not beyond. If one defines space to include volumes outside the confines of the matter of the universe (considering there is only one universe), what would be the value or meaning of such a definition that was unrelated to matter, None! ...

Let me pose your rhetorical question in somewhat different terms. I would be very interested in hearing opinions other than my own.

 

The current observable universe has a (comoving distance) radius of approximately 46 billion light years. Additionally, the farthest (comoving) distance we will ever be able to detect is:

 

...This future visibility limit is calculated to be at a comoving distance of 19 billion parsecs (62 billion light years), which implies the number of galaxies that we can ever theoretically observe in the infinite future (leaving aside the issue that some may be impossible to observe in practice due to redshift...

(ref. http://en.wikipedia....rvable_universe )

 

If light - and by implication, any sort of information, signal, or effect - beyond a comoving distance of 62 billion light years can never reach us, does it make any difference at all to our observations what lies beyond?

 

If one defines space to include volumes outside the confines of that which we will ever be able to observe and beyond the effects of which we will ever be able to detect, what would be the value or meaning of such a definition that's unrelated to any knowledge we can possibly have?

 

Chris

[pantheory]

csmyth3025,

 

I made a few addendums to my last post which you were not able to read since your posting was made before my amendments. I do not think my changes would have effected your response, only that you can now look at my comments concerning an infinity of space which was the primary change and addendum.

 

Chris, I generally agree with your comments but think that definitions of words are very important, not only for discussions of concepts involving those words like this thread for instance, but to have more clear mental images of reality in general from at least one perspective. One related question that arises I think is this: Is reality relatively simple or is it mind boggling? If one always accepts the idea that reality is mind boggling then I think they will not be be able to ask the proper internal questions that might enable a better understanding of reality, which for most people I believe is an ongoing task.

 

(your quote)

 

"...If one defines space to include volumes outside the confines of that which we will ever be able to observe and beyond the effects of which we will ever be able to detect, what would be the value or meaning of such a definition that's unrelated to any knowledge we can possibly have?"

 

I'm not suggesting that a definition of space should include or exclude theoretical volumes of space outside of what will ever be observable, I'm proposing the exclusion of what some propose as an infinite volume, from definitions of space. I'm discussing a definition of space that might answer the primary question of this thread, where does space end. Your question in quotes I think is a valid one but it seems to me like you are saying something like: what difference does it make how the universe started or any other question in cosmology that we could never know? We have evidence of things through observation and our nature as humans is to try to figure it all out so that we can better understand reality. A great number of intelligent people don't care about things that we could never know. What difference does it make exactly how old the universe is or how far it extends, as in your example. My contention and hope is that if one has the understands concerning the definitions of the words space and time as I have explained them, then I think their understandings of reality in general will improve. In this case without new discoveries in the cosmos, I think that by better definitions alone, understandings of reality can improve. Of course it is always better to make clear your meanings concerning words that one is using in conversation that could be ambiguous. Such words need to be clarified for meaningful conversation anyway -- and "where does space end" is after all the question/ subject of this thread

 

Most realize that there is no mainstream consensus concerning an answer to this question "where does space end," so this is my take concerning what I think is a preferable answer.

Edited June 18, 2011 by pantheory

[Marqq]

Marqq, you seem to have based your ideas on incredulity at alternative explanations. Do you think that is wise?

Well, yeah.

Without skepticism ([acr=also known as]a.k.a.[/acr] incredulity), we might still believe that the earth is the back of a giant turtle swimming through the sea, or other such silly notions. Humans have a long and sordid history of using pure fancy to explain how the world works. We all have some schema comprised of our observances (with a good dose of imagination) forming our basic understanding of reality. Many such explanations are obvious fantasy to us (turtle-shell earth, astrology, weather deities, god is a flying spaghetti-monster, etc.). The underlying fallacy in each of these theories is simply their overcomplexity; they are giant leaps which are assumed and explained retroactively from said leap, to link eventually to whatever is being explained.

 

A, then what B?

C, thus if A, B.

 

My ideas are not like this model at all. I start with my most basic model of reality: [acr=reality]R[/acr] = [acr=substance]s⁺[/acr] && [acr=non-substance (vacuum)]s^-[/acr]. Increasing amounts of substance in an area create exponentially increasing levels of outward pressure (the tendency to expand volume), but can never truly reach infinity unless the entire universe were contained in a finite area (or any amount of substance were forced to occupy a one-dimensional point or [acr=this may be the origin of string theory now that I think about it]two-dimensional line/string[/acr]). An infinite vacuum, on the other hand, could exist, theoretically. If such an infinite vacuum did exist, it's power would be infinite, drawing the entire universe into its one-dimensional volume instantaneously. Luckily, such an instance would require infinite power to create, so vacuum can only exist as a near-zero (but not zero) percentage of substance. From this framework, I constructed my tween theory. From my skepticism, I found my own answer. And I have no reservations about the possibility that my theory can't be experimentally proven, because I built it up logically from what cannot be denied. It's a sound argument, as far as I can tell, but feel free to put it to the test or to find a simpler alternative .

 

 

My own theory concerning the structure of matter is similar to yours. String-like strands of elementary particles (in my case) in 3 dimensions which form loops and spin (...) much less complicated than the 11 or more dimensions of conventional string theory. (...) The math of string theory requires that the width of zero is used but actually the width could theoretically be many times smaller than a plank length (...) would enable the use of zero in the calcs. (...)

 

As to how far space extends, (...) space only extends to the extent that matter exists, within the same confines, and not beyond. If one defines space to include volumes outside the confines of matter in the universe (...), what would be the value or meaning of such a definition that was unrelated to matter? (...)

Thank you for explaining that strings could have width greater than zero. I'm still not sure what to make of the rest of string theory, though. I'll certainly read more into it as well as pan theory.

 

 

I would certainly define space (or the universe) as all volume within and beyond the matter we've thus far perceived. By definition, our universe includes 'all that is', or everything rolled into one. Even if no matter exists outside our visible world, it would have an infinite volume, like the space between matter within our world. It DOES exist, even only as vacuum. Further, would not that volume of pure vacuum pull violently at the edges of what we can see? Would it not spread the farthest reaches of our world drastically into the void? A tangible fabric to reality must exist, even beyond our small volume of perception, filling in the space between. and on that fabric, there must exist other clusters where matter has been forced into existence. In any case, whatever is beyond our perceptible space, it would invariably have some effect on what is perceptible.

 

(...)

If light - and by implication, any sort of information, signal, or effect - beyond a comoving distance of 62 billion light years can never reach us, does it make any difference at all to our observations what lies beyond?

 

If one defines space to include volumes outside the confines of that which we will ever be able to observe and beyond the effects of which we will ever be able to detect, what would be the value or meaning of such a definition that's unrelated to any knowledge we can possibly have?

 

Chris

I hate to overuse ad absurdum, but imagine a time when it was believed that the earth had an edge, beyond which any travel would end in a very long fall... Knowing what exists beyond what we think we can travel, or what we think can affect us has definite value. In the case of this discussion, such theory could eventually lead to a means of broaching the apparent impossibility. Knowing what exists (or doesn't) out there could give vital clues to what exists in here. In the style of Pascal's wager, I argue: Learn everything! Learning something you'll never use has little disadvantage. Ignoring knowledge, and later finding a need for it, is disastrous.

[csmyth3025]

csmyth3025,

 

csmyth3025, on 17 June 2011 - 04:01 PM, said:

...If one defines space to include volumes outside the confines of that which we will ever be able to observe and beyond the effects of which we will ever be able to detect, what would be the value or meaning of such a definition that's unrelated to any knowledge we can possibly have?

 

Chris, I generally agree with your comments but think that definitions of words are very important...

 

...I'm not suggesting that a definition of space should include or exclude theoretical volumes of space outside of what will ever be observable, I'm proposing the exclusion of what some propose as an infinite volume, from definitions of space. I'm discussing a definition of space that might answer the primary question of this thread, where does space end. Your question in quotes I think is a valid one but it seems to me like you are saying something like: what difference does it make how the universe started or any other question in cosmology that we could never know? We have evidence of things through observation and our nature as humans is to try to figure it all out so that we can better understand reality...

 

...so this is my take concerning what I think is a preferable answer.

The sentences in your original post #635 that caught my eye were quoted by me as follows:

 

pantheory, on 17 June 2011 - 02:46 PM, said:

...As to how far space extends, I believe is easy for most people to understand the true answer once it is explained to them. To explain the correct definition, I believe, is that space exists to the extent that matter exists, within the same confines, and not beyond. If one defines space to include volumes outside the confines of the matter of the universe (considering there is only one universe), what would be the value or meaning of such a definition that was unrelated to matter, None! ...

 

In the first two sentences you used phrases like "..true answer..." and "...correct definition..." Now you're saying that "...this is my take concerning what I think is a preferable answer..."

 

I would have to agree with your current reply "...that definitions of words are very important..."

 

In your third sentence you characterized a universe (or "...volume of space...") that contains no matter as having no value or meaning. Now you're saying "...I'm not suggesting that a definition of space should include or exclude theoretical volumes of space outside of what will ever be observable, I'm proposing the exclusion of what some propose as an infinite volume, from definitions of space...." This current statement conflicts with your former dismissal of a space devoid of matter - a so-called de Sitter space:

 

In the language of general relativity, de Sitter space is the maximally symmetric, vacuum solution of Einstein's field equations with a positive (repulsive) cosmological constant Λ (corresponding to a positive vacuum energy density and negative pressure). When n = 4 (3 space dimensions plus time), it is a cosmological model for the physical universe...

(ref. http://en.wikipedia....De_Sitter_space )

 

NOTE: A vacuum solution is a solution of a field equation in which the sources of the field are taken to be identically zero. That is, such field equations are written without matter interaction (i.e.- set to zero).

(ref. http://en.wikipedia.org/wiki/Vacuum_solution )

 

Your current statement also conflicts with itself in that the first part of it says "...I'm not suggesting that a definition of space should include or exclude theoretical volumes of space outside of what will ever be observable..." and the second part of it says "...I'm proposing the exclusion of what some propose as an infinite volume..."

 

Aside from your statement being self-contradictory, your proposal to exclude an infinite universe has no observational or theoretical basis. The universe may be finite or it may be infinite. Either one of these conditions is permitted in the currently accepted Lambda-CDM standard cosmological model.

 

Observationally, the latest data shows that the universe is "flat" within about 2%:

 

The WMAP has confirmed that the universe is flat with only a 2% margin of error. Within the Friedmann-Lemaître-Robertson-Walker (FLRW) model, the presently most popular shape of the Universe found to fit observational data according to cosmologists is the infinite flat model, while other FLRW models that fit the data include the Poincaré dodecahedral space and the Picard horn.

(ref. http://en.wikipedia....of_the_Universe )

 

On a side note, you probably already know that it's generally considered bad forum manners to change words in an existing post that change the meaning of the sentences in which they're contained. If you edit a previous post to correct spelling or math errors (or to add material) it should be noted in the edited post. This will help to avoid confusing those who are just starting to read the last few posts and the replies to those posts.

 

Chris

 

Edited to add NOTE about vacuum solutions

Edited June 18, 2011 by csmyth3025

[Ophiolite]

Well, yeah.

Without skepticism ([acr=also known as]a.k.a.[/acr] incredulity), we might still believe that the earth is the back of a giant turtle swimming through the sea, or other such silly notions.

Nevertheless, your incredulity, as expressed several times, is of the kind "I can't believe that's true", for no other reason than "I can't believe that's true". That approach might, by luck, lead you to a correct answer, but it would be by a flawed, illogical methodology.

 

The underlying fallacy in each of these theories is simply their overcomplexity;

This obsession with simplicity seems a natural extension of incredulity at complex explanations. There is no known 'universal law' that states the universe need be simple (or complex). You have made an arbritary choice in favour of simple. That's not scientific.

 

My ideas are not like this model at all.............From this framework, I constructed my tween theory. ,,,,,,,,,, And I have no reservations about the possibility that my theory can't be experimentally proven, because I built it up logically from what cannot be denied.

1. Please stop calling it a theory when it is at best a speculation.

2. Since you have developed this 'theory' please post the mathematics describing it. Since it is a simple 'theory' I am optimistic that my maths will be good enough to make sense of it.

 

 

Ignoring knowledge, and later finding a need for it, is disastrous.

Sage advice. At this point I am not sure you have followed it.

[pantheory]

csmyth3025,

"People before me believed that if all the matter in the universe were removed, only space and time would exist. My theory proves that space and time would disappear along with matter" Einstein.

Chris, all of my statements above are related to the above quote by Einstein. Since there is no consensus in cosmology today concerning one definition of space, my opinion accordingly is that space ends where both matter and field end and its definition should not include the possibility of infinite space if neither matter nor field (ZPF) are believed to be infinite in quantity. The idea is that space without matter or field within it, would be meaningless or you might call it undefined -- such as a quantity divided by zero.

 

Our last postings crossed paths during my amendment, adding and changing a few sentences. Sorry about that

Edited June 18, 2011 by pantheory

[MigL]

Marqq and pantheory, you guys do realise that a theory is developed as a model of reality such that things can be explaned and predicted.

 

In the case of string theory, I realise the math is horrendous, but its there for a reason. String theory attempts to unite the fundamental forces of the universe. GR and the 4 dimensions of space/time are sufficient for gravity. Five dimensions sre sufficient for gravity and electomagnetism ( see Kaluza-Klein and Planck size rolled up dimensions ). To explain the weak and strong nuclear forces, another five, six or possibly up to 21 more dimensions are needed, all rolled up at Planck lengths. It would seem to me that to explain the chirality or handedness of the weak force we need an odd number of spatial dimensions so 10 and 26 total ( including time ) seem to work but eleven doesn't. However, current strng theory is pushing towards 11 dimensions, so I'm probably wrong.

 

So... just saying your theory is simpler doesn't cut it. What is your theory trying to accomplish ? It certainly doesn't seem to be trying to unite forces. As to making valid predictions please tell us what predictions, if any, your 'theory' might make so that it may be tested. If it doesn't make any, its on even more precarious footing than string theory which also doesn't make any predictions , but it at least manages fundamental force unification.

[csmyth3025]

csmyth3025,

 

Quote"People before me believed that if all the matter in the universe were removed, only space and time would exist. My theory proves that space and time would disappear along with matter" Einstein.

 

Chris, all of my statements above are related to the above quote by Einstein. Since there is no consensus in cosmology today concerning one definition of space, my opinion accordingly is that space ends where both matter and field end and its definition should not include the possibility of infinite space if neither matter nor field (ZPF) are believed to be infinite in quantity. The idea is that space without matter or field within it, would be meaningless or you might call it undefined -- such as a quantity divided by zero.

 

Our last postings crossed paths during my amendment, adding and changing a few sentences. Sorry about that

 

Do you have a reference for that quote?

 

On the subject of this thread: "Where does the Universe end? It must end somewhere!", the title itself states an assumption based on "common sense". Common sense doesn't include training in mathematics, logical deduction and experimental research, though. Science is very rigorous about these.

 

The quote you attributed to Einstein seems to make common sense, but Einstein, as a scientist, also developed the Special Theory of Relativity in 1905. In this theory he proposed that an object's mass would increase and it's dimension along the axis of travel would shorten and its clock would slow down as it's speed relative to a "stationary" observer approached the speed of light. All of these notions seemed contrary to "common sense" at the time, but Einstein backed up his proposals with rigorous mathematics and sound logical deductions based on known science. His theory was able to explain known experimental observation (the null result of the Michelson-Morley experiment) in a mathematically precise way.

 

To those who haven't studied physics and mathematics there are a lot of science concepts that don't seem to "make sense" or are "too complex to understand". This doesn't make them wrong.

 

Most self-proposed alternative theories are based on "common sense" analogies that describe light as "...being like this..." or gravity as "...being like that..." They don't meet the tests of mathematical rigor and predictive ability that real scientific theories must in order to be accepted.

 

Those in this forum who have extensive knowledge about the scientific process and the scientific theories we discuss here will always guage the value of proposed theories against the rigor they know has already been demanded of existing theories like Special and General Relativity and the Lambda-CDM standard cosmological model. They want to see mathematical formulas and observational evidence, not analogies.

 

Chris

[pantheory]

csmyth3025,

 

To those who haven't studied physics and mathematics there are a lot of science concepts that don't seem to "make sense" or are "too complex to understand". This doesn't make them wrong.

 

I agree totally, and can even say that many who even know the present interpretations still think some of it does not make logical sense, like myself for instance. I am well educated on such matters. The examples you gave I believe I understand the logic, the why's and reasoning, but some interpretations that I am aware of I think seem illogical and I believe are just wrong -- but maybe that's just me. Mathematics has its own logic like Quantum Mechanics, for instance, but that does not necessarily mean that all the verbal interpretations/ explanations of Quantum Theory (QT) are correct, does it? As theories go the verbiage of QT seems like the least logical of all well known theories today, yet few doubt (including me) that the mathematics of QM is the best thing going to predict behaviors or interactions concerning particles in the quantum world.

 

Because a theory is not logical does not mean that it should be dismissed in some way, only that the explanations of it should be looked at using a more critical approach, in my opinion.

 

 

Do you have a reference for that quote?

 

My references:

http://www.sciencefo...430#entry612430 the O.P.

 

http://en.wikipedia....i/Hole_argument

 

Einstein's resolution, last quote.

Edited June 19, 2011 by pantheory

[pantheory]

Marqq and pantheory, you guys do realise that a theory is developed as a model of reality such that things can be explaned and predicted.

 

In the case of string theory, I realise the math is horrendous, but its there for a reason. String theory attempts to unite the fundamental forces of the universe. GR and the 4 dimensions of space/time are sufficient for gravity. Five dimensions are sufficient for gravity and electomagnetism ( see Kaluza-Klein and Planck size rolled up dimensions ). To explain the weak and strong nuclear forces, another five, six or possibly up to 21 more dimensions are needed, all rolled up at Planck lengths. It would seem to me that to explain the chirality or handedness of the weak force we need an odd number of spatial dimensions so 10 and 26 total ( including time ) seem to work but eleven doesn't. However, current string theory is pushing towards 11 dimensions, so I'm probably wrong.

 

So... just saying your theory is simpler doesn't cut it. What is your theory trying to accomplish ? It certainly doesn't seem to be trying to unite forces. As to making valid predictions please tell us what predictions, if any, your 'theory' might make so that it may be tested. If it doesn't make any, its on even more precarious footing than string theory which also doesn't make any predictions , but it at least manages fundamental force unification.

My opinion is that strings are the right configuration concerning the foundations of matter, but extra dimensions are not needed and nothing needs to be unified, again -- in my opinion. The reason is that my own model does not adhere to the primal, a priori idea of fundamental forces. Einstein proposed, for instance, that gravity was not a force but instead was caused by the warping of space. Even though I do not adhere to the warped-space idea (one reason is that space appears to be flat) but I do believe that gravity is not a force as Einstein proposed. But in the same way I also believe that none of the other "fundamental pulling forces" are really forces either, but instead can be explained by mechanical mechanisms via string theory. Therefore accordingly reality would be simpler and no forces would need unification since there would be generally nothing fundamental to unify.

 

This section being the science forum, I realize that the model that I just mentioned or any version of string theory in general, would be contrary to the standard model of particle physics. Although I think there may be some evidence and much logic and predictions which might support this "simple universe, theory of everything" model, the elaboration of the details probably belongs in the Speculation Forum. I will start such a thread there if anyone would be interested. Marqq are you there ? or others ?

 

But yes you are correct, conventional String Theory is an attempt to create a General Unified theory/ model unifying the so-called fundamental forces. But on the other hand if I am right, no new math (other than a Minkowsky type string theory explaining elementary particles) would be needed concerning unification of forces because there would be no fundamental forces to unify and the universe would be a far simpler place. On a separate matter I think both QM and GR need to be modified (or replaced) to better understand reality and as a result realize why these models were not compatible. I think the key is related to the "hidden variables" idea supported by Einstein and related papers today that relate to hidden variables such as dark matter, Higg's particles, gravitons, quantum foam, ZPF anomalies, etc. etc. But of course more evidential support will probably be needed to have such proposals more seriously considered.

Edited June 19, 2011 by pantheory

[csmyth3025]

csmyth3025,

 

"People before me believed that if all the matter in the universe were removed, only space and time would exist. My theory proves that space and time would disappear along with matter" Einstein.

 

Chris, all of my statements above are related to the above quote by Einstein. Since there is no consensus in cosmology today concerning one definition of space, my opinion accordingly is that space ends where both matter and field end and its definition should not include the possibility of infinite space if neither matter nor field (ZPF) are believed to be infinite in quantity. The idea is that space without matter or field within it, would be meaningless or you might call it undefined -- such as a quantity divided by zero....

The quote you attribute to Einstein does, indeed seem to be a central part of his cosmological viewpoint.

 

I have a copy of the fifteenth edition of Einstein's book "Relativity The Special and the General Theory" (1952, Methuen & Co.) which includes a Note to the Fifteenth Edition authored by Einstein in which he says:

 

In this edition I have added, as a fifth appendix, a presentation of my views on the problems of space in general and on the gradual modification of our ideas on space resulting from the influece of the relativistic viewpoint. I wished to show that space-time is not necessarily something to which one can ascribe a separate existance, independently of the actual objects of physical reality. Physical objects are not in space, but these objects are spatially extended. In this way the concept 'empty space' loses its meaning.

 

In the fifth appendix, however, he clearly states:

 

Thus Descartes was not so far from the truth when he believed he must exclude the existence of an empty space. The notion indeed appears absurd, as long as physical reality is seen exclusively in ponderable bodies. It requires the idea of the field as the representative of reality, in combination with the general principle of relativity, to show the true kernel of Descartes's idea; there exists no space 'empty of field'.

(page 190)

 

In the fifth appendix Einstein goes into some detail describing the notion of a field and, particularly, a pure gravitational field.

 

We know from the Einstein Field Equations that the stress-energy tensor is the source of the gravitational field:

 

The stress–energy tensor (sometimes stress–energy–momentum tensor) is a tensor quantity in physics that describes the density and flux of energy and momentum in spacetime, generalizing the stress tensor of Newtonian physics. It is an attribute of matter, radiation, and non-gravitational force fields. The stress-energy tensor is the source of the gravitational field in the Einstein field equations of general relativity, just as mass is the source of such a field in Newtonian gravity.

(ref. http://en.wikipedia....s-energy_tensor )

 

Eistein has sent mixed signals on the question of the role matter plays in space-time. At one time he's said that space-time can't exist without matter and (in 1952, at least) he's also said that "there exists no space empty of field".

 

As I mentioned in my earlier post, there are "vacuum" solutions the the EFE that do not require the presence of matter (the de Sitter universe being one).

 

We can apply the cosmological principle, however, and since there is matter in our observable universe there is no reason to suspect that the rest of the universe is any different. It's important to note that the presence or absence of matter has no bearing on whether the universe is finite or infinite.

 

Chris

[pantheory]

csmyth3025,<br><br>Very relevant info and I think good Einstein quotes. Thanks for the edification Chris.<br><br>

Einstein has sent mixed signals on the question of the role matter plays  in space-time. At one time he's said that space-time can't exist without  <b>matter</b> and (in 1952, at least) he's also said that "there exists no space <b>empty of field</b>"

.<br>I don't perceive these quotes as necessarily conflicting since it is commonly believed today that the field (the ZPF) can and does exist in the absence of matter, but that matter does not exist in the absence of field, and accordingly space does not exist in the absence of both, which relates to the question of this thread.<br><br>

....It's important to note that the presence or absence of matter has no bearing on whether the universe is finite or infinite.

<br>I think the question of whether the universe is finite or infinite is primarily based upon the definitions of the words "space" and "infinite" concerning a flat space/ universe. If space that is devoid of matter and field is believed to have existence rather than simply being non-existent, then the universe would be infinite by definition unless bounded by a "warped" geometry of space.   And conversely the universe must necessarily be finite if space does not exist outside the confines of matter and field, when starting from a finite beginning entity such as the BB model.   In theoretical physics (as far as I know ) something finite like a beginning entity, could not become something infinite through evolution excepting by a change in the geometry of space, or if totally empty vectors or infinite voids are considered distances or space respectively, by definition<br><br>regards,  Forrest Edited June 20, 2011 by pantheory

[csmyth3025]

csmyth3025,

 

Very relevant info and I think good Einstein quotes...

 

...I don't perceive these quotes as necessarily conflicting since it is commonly believed today that the field (the ZPF) can and does exist in the absence of matter, but that matter does not exist in the absence of field, and accordingly space does not exist in the absence of both, which relates to the question of this thread...

 

I'm afraid I don't follow your logic: If "There exists no space empty of field" and there are fields which do not require matter in order to exist, why does the existence of space require both a field and matter?

 

This question focuses on the narrow question of whether the laws of physics as we know them allow for such a unverse. There is, of course, the other purely philosophical question of what a universe without matter (and, presumably, without observers) means.

 

Chris

 

And conversely the universe must necessarily be finite if space does not exist outside the confines of matter and field, when starting from a finite beginning entity such as the BB model. In theoretical physics (as far as I know ) something finite like a beginning entity, could not become something infinite...

Forrest

(bold added by me for emphasis)

 

As far as I know, the big bang theory postulates that the universe started in a very hot and dense state and evolved from there. The theory postulates no initial conditions for the "beginning entity".

 

People generally assume that this beginning entity must have occupied a finite amount of space and contained a finite amount of energy. That's just how they visualize the big bang and how the media usually depicts the so-called "big bang singularity".

 

The big bang theory places no such restriction on the beginning entity. It could just as easily have been infinite. The inflationary epoch would have quickly expanded the "rest" of the universe beyond our cosmic horizon.

 

Chris

[pantheory]

csmyth3025,

 

(my quote)

 

....I don't perceive these quotes as necessarily conflicting since it is commonly believed today that the field (the ZPF) can and does exist in the absence of matter, but that matter does not exist in the absence of field, and accordingly space does not exist in the absence of both, which relates to the question of this thread...

(your quote)

I'm afraid I don't follow your logic: If "There exists no space empty of field" and there are fields which do not require matter in order to exist, why does the existence of space require both a field and matter?

You are correct. Space accordingly does not require matter. The logic is that space requires something that has existence within its boundaries (between two or more points all of which must include at least field within its entire domain) to enable any meaning of its own existence. Space must accordingly contain field within it and may or may not also include matter within the same distance/ volume/ boundaries along with the field, for such a volume or distance to accordingly be considered space based upon my own model and I believe Einstein's according to his quotes. Accordingly hypothetical void-volumes that some might call space would be solely imaginary, non-existent, science-fiction volumes and distances.

 

As far as I know, the big bang theory postulates that the universe started in a very hot and dense state and evolved from there. The theory postulates no initial conditions for the "beginning entity".

 

People generally assume that this beginning entity must have occupied a finite amount of space and contained a finite amount of energy. That's just how they visualize the big bang and how the media usually depicts the so-called "big bang singularity".

 

The big bang theory places no such restriction on the beginning entity. It could just as easily have been infinite. The inflationary epoch would have quickly expanded the "rest" of the universe beyond our cosmic horizon.

As to the question of a beginning infinite entity, again the word infinite must be precisely defined. Most assert that theoretically a beginning BB entity that might have been infinitely small would have been at the same time infinite in density, whatever that or its implications might mean. No theorist, that I am aware of, consider that such an entity could have also been infinite in its extension or infinite concerning any other meaning of the word infinite. As far as I know all BB theorists believe that the beginning entity was, or soon became, of finite dimension, extension and potential. I know of no BB papers asserting otherwise. From a dimensionally finite beginning BB entity of limited potential, only a finite universe could ever result unless the concept of totally vacant space is given some hypothetical meaning such as "potential space" for instance which might be perceived as having infinite extension possibilities concerning the many infinite-expansion versions. Even in these models the universe would always be finite concerning its extension or any thing else, at any present or future time.

Edited June 20, 2011 by pantheory

[BJC]

csmyth3025, pantheory

 

If you please, could either of you clarify some of your terms?

 

matter, field: You seem to use matter in the conventional "particle" sense and refer to a "field" as separate entity. In GR and in QM matter has a field formulation so i am unsure as to how, or even why, you are separating matter and field. I would think we only need particle type matter to measure time and space but this technological constraint should have no bearing on the extent of space.

 

At one point in the topic there was a reference to "how Einstein" viewed matter, (his direct quote)

The Foundations of the General Theory of Relativity (1916), Chapter 14:

...

We make a distinction hereafter between "gravitational field" and "matter" in this way, that we denote everything but the gravitational field as "matter." Our use of the word therefore includes not only matter in the ordinary sense, but the electromagnetic field as well.

 

There is also the point that space-time is defined as the structure or geometry of the Gravitational field so would not space-time exist wherever a gravitational field exists? In particular the gravitational field defined by the de Sitter vacuum energy field (or cosmological constant) solution.

 

If "Inflation" is considered the expansion of vacuum energy field is considered ~1,000 times the size of our universe and our universe is contained within one of many vacuum energy bubbles. (our universe is appx. the observable universe) - so wouldn't space be at least 4 orders of magnitude larger than our universe.

 

................. speculation ................

And finally if "inflation" the initial field is proposed as a high potential vacuum energy field (a constant static field sometimes referred to as quantum foam) then this field could be described as a de Sitter field with a constant or zero time. If so, this would mean space is and always was.