derek w Posted March 14, 2013 Posted March 14, 2013 Is the universe expanding,because it is collapsing from 4 dimensions to only 3 dimensions?
ACG52 Posted March 15, 2013 Posted March 15, 2013 Is the universe expanding,because it is collapsing from 4 dimensions to only 3 dimensions? The universe is expanding because there is more space being created between everything.
derek w Posted March 15, 2013 Author Posted March 15, 2013 If you start with 4 dimensions (x,y,z,t),where (x,y,z) axis are infinitely small and (t) axis is infinitely large,then you have a 4 dimensional string. if the (x,y,z) axis then expands,the (t) axis must be collapsing. e.g:- if a 3 dimensional object like a ball of plasticine collapses and spreads out over a 2 dimensional surface,1 axis is shrinking(collapsing),while the other 2 axis are expanding.
pwagen Posted March 15, 2013 Posted March 15, 2013 e.g:- if a 3 dimensional object like a ball of plasticine collapses and spreads out over a 2 dimensional surface,1 axis is shrinking(collapsing),while the other 2 axis are expanding. But if you blow up the balloon, every axis is expanding. Why can't that analogy be applied to the universe?
derek w Posted March 15, 2013 Author Posted March 15, 2013 But if you blow up the balloon, every axis is expanding. Why can't that analogy be applied to the universe? The 2 dimensional surface of the the balloon is expanding,because the thickness of the rubber is shrinking(a collapsing axis). If you want a 3 dimensional expansion some other axis must be shrinking(collapsing).
elfmotat Posted March 15, 2013 Posted March 15, 2013 The 2 dimensional surface of the the balloon is expanding,because the thickness of the rubber is shrinking(a collapsing axis). If you want a 3 dimensional expansion some other axis must be shrinking(collapsing). Space isn't "made" of anything. It's not a rubber sheet that decreases in thickness when stretched. You're taking the analogy far too seriously. I'll give you a little technical insight: say the universe is flat and one-dimensional. Now we label each point in the universe with a coordinate x. How do we find the distance between two points x1 and x2? We need to use something called a "metric." It tells us the distance between two infinitely close points. If space isn't expanding then the metric is very simple: [math]ds=dx[/math] where ds is an infinitely small distance and dx is an infinitely small change in the x-coordinate. If we want to find the distance between two points x1 and x2 we just take an integral: [math]s=\int_{x_1}^{x_2}dx=x_2-x_1[/math] Now let's say that the distance between two points isn't always the same, but actually depends on a function of time (i.e. space can be expanding or contracting): [math]ds=f(t)dx[/math] Now the distance between two points is: [math]s=\int_{x_1}^{x_2}f(t)dx=f(t)\left [ x_2 -x_1 \right ][/math] If we let [math]f(t)=kt[/math] for some constant k, then space will expand at a constant rate. If we let [math]f(t)=kt^2[/math], space is expanding with an accelerating rate. [math]f(t)=\frac{k}{t}[/math] would describe a contracting space. The function f(t) which describes our physical universe is determined by the Friedmann Equations (which come from the Einstein Field Equations).
John Cuthber Posted March 16, 2013 Posted March 16, 2013 In order to shrink over any finite period of time from 4 dimensions to three, at some point it would need to have three and a a half dimensions. Is that a meaningful concept? If not, how could the "shrinking" happen?
derek w Posted March 16, 2013 Author Posted March 16, 2013 In order to shrink over any finite period of time from 4 dimensions to three, at some point it would need to have three and a a half dimensions. Is that a meaningful concept? If not, how could the "shrinking" happen? Not if you started with a 4 dimensional string,where (x,y,z) is infinitely small and (t) is infinitely large. (t) can shrink forever and never reach (t=0),therefore (x,y,z) can expand forever. Plus you could have an infinite number of 4 dimensional strings. I am not sure what you mean by at some point it would need to have three and a half dimensions.there would always be 4 dimensions.
John Cuthber Posted March 16, 2013 Posted March 16, 2013 (edited) Well, since you said "Is the universe expanding,because it is collapsing from 4 dimensions to only 3 dimensions?" I assumed that you mean that it was making some sort of transition from 4 dimensions to three. That's clearly inconsistent with the assertion that "There would always be 4 dimensions." Which do you mean? Do you mean it ends up with three dimensions (in which case it must go through a stage of having 3.5) or do you mean it continues to have 4 dimensions in which case your initial post makes no sense because there is no such collapse? Strictly , the requirement for 3.5 (or even pi) dimensions only occurs if the transition is gradual, but since you said "is collapsing" you imply an on-going process which we are currently in the middle of. Edited March 16, 2013 by John Cuthber
Delta1212 Posted March 16, 2013 Posted March 16, 2013 Well, since you said "Is the universe expanding,because it is collapsing from 4 dimensions to only 3 dimensions?" I assumed that you mean that it was making some sort of transition from 4 dimensions to three. That's clearly inconsistent with the assertion that "There would always be 4 dimensions." Which do you mean? Do you mean it ends up with three dimensions (in which case it must go through a stage of having 3.5) or do you mean it continues to have 4 dimensions in which case your initial post makes no sense because there is no such collapse? Strictly , the requirement for 3.5 (or even pi) dimensions only occurs if the transition is gradual, but since you said "is collapsing" you imply an on-going process which we are currently in the middle of. I'm not supporting the idea that we're collapsing from 4 to 3 dimensions, but this argument doesn't necessarily hold. Let's say I have some ice that is melting. Eventually, I will have no ice because it will have melted. Does that mean I ever had half-ice? At some point I must have had an ice cube that was half the size of what I originally started with, but that ice would still be entirely ice. Similarly, a dimension might, hypothetically, shrink until it popped out of existence, but that doesn't mean you'd ever have half a dimension, just a dimension that was smaller than before.
John Cuthber Posted March 16, 2013 Posted March 16, 2013 Did you read this bit of what I said? Strictly , the requirement for 3.5 (or even pi) dimensions only occurs if the transition is gradual, but since you said "is collapsing" you imply an on-going process which we are currently in the middle of. That's what I meant. This "shrink until it popped out of existence" is the issue. What about when you were half way through the pop? If it's a sudden change then there isn't a half way stage but his wording tells us that the change is gradual. For any particular bit of the ice, the change is sudden. that's a different issue.
Delta1212 Posted March 17, 2013 Posted March 17, 2013 Did you read this bit of what I said? Strictly , the requirement for 3.5 (or even pi) dimensions only occurs if the transition is gradual, but since you said "is collapsing" you imply an on-going process which we are currently in the middle of. That's what I meant. This "shrink until it popped out of existence" is the issue. What about when you were half way through the pop? If it's a sudden change then there isn't a half way stage but his wording tells us that the change is gradual. For any particular bit of the ice, the change is sudden. that's a different issue. First of all, I'm not the OP, and don't agree with the OP, so I didn't say "is collapsing" at any point. Secondly, just because the transition is instantaneous doesn't mean there isn't a process leading up that that transition which doesn't necessarily lead to in between forms any more than a lit fuse leads to half-exploded dynamite. If a dimension was shrinking and the end result of that shrinkage was that it would disappear from existence, I would say that the dimension is collapsing. I would never say that it reaches a point where it is half a dimension. I don't think that is actually happening, of course, but a bad argument doesn't become a good argument just by being in favor of the right stance.
DevilSolution Posted March 17, 2013 Posted March 17, 2013 If you start with 4 dimensions (x,y,z,t),where (x,y,z) axis are infinitely small and (t) axis is infinitely large,then you have a 4 dimensional string. if the (x,y,z) axis then expands,the (t) axis must be collapsing. e.g:- if a 3 dimensional object like a ball of plasticine collapses and spreads out over a 2 dimensional surface,1 axis is shrinking(collapsing),while the other 2 axis are expanding. You answered your own question by your own definitions of the axis's; If (t) is infinitely large then it cant be shrunk, only the perception of its size from a relative observation shows it shrinking.
John Cuthber Posted March 17, 2013 Posted March 17, 2013 "...any more than a lit fuse leads to half-exploded dynamite." Actually, that's what usually happens. The velocity of detonation for dynamite is about 7 KM/S (I'm using the value for straight NG so it's not a brilliant estimate). About 7 metres in a millisecond or 7 centimetres in 10 microseconds A typical stick of dynamite is something like 15 cm long so, about 10 microseconds after the detonator fires, you have got half exploded dynamite. My point remains, if the change from 4 to 3 is gradual then there is a point where it's 3.5. If the change is instant then there is no half way house. But the OP clearly says that it "is collapsing from 4 to only 3" "Is collapsing" means that the collapse from 4 to 3 is an event which takes a finite time and we are currently at a point during that interval. "will collapse or "collapsed" would be different.
Delta1212 Posted March 17, 2013 Posted March 17, 2013 I knew the half-exploded dynamite analogy wasn't going to work, but I hadn't thought of a better one at that point. Let's try this: A star "is collapsing" into a black hole. At what point is it half star/half black hole?
John Cuthber Posted March 17, 2013 Posted March 17, 2013 At the point where half of the mass is inside the event horizon. (The middle will collapse first, because it's densest.) Who cares? You keep trying to talk about fast events, but the OP is talking about one which is at least slow enough to let people post stuff about it.
Delta1212 Posted March 17, 2013 Posted March 17, 2013 There is no event horizon unless there's a black hole. You can't have half a black hole. There isn't one and then there is one. This doesn't prevent people from (accurately) stating that a star "is collapsing" into a black hole, even if there isn't a partial black hole that is slowly emerging during the full duration of the collapse. There are plenty of valid arguments against the OP's idea, but the idea that a collapsing [something] must, at some point, become half a [something] is not one of them.
John Cuthber Posted March 17, 2013 Posted March 17, 2013 "There is no event horizon unless there's a black hole. You can't have half a black hole. There isn't one and then there is one." Right on all three counts. And when one forms in the middle of a start it grows (not very rapidly) until it has drawn essentially the whole star in. At the point where half of the star's mass is in the black hole it ticks the box for this "At what point is it half star/half black hole?" And it still isn't relevant. There are two ways to go from 4 to 3. One is suddenly and the other is gradually. If it happens suddenly there is no point at which it is 3.5 but, If it happens gradually then there is a point at which it is 3.5 (and on either side of that point it's 3.4 and 3.6). The OP states that the change is not sudden.
derek w Posted March 17, 2013 Author Posted March 17, 2013 If the (x,y,z) axis was collapsing and the (t) axis expanding,would that not be a black hole in the 3 dimensional space?
SplitInfinity Posted March 17, 2013 Posted March 17, 2013 Is the universe expanding,because it is collapsing from 4 dimensions to only 3 dimensions? First of all...Matter cannot exist in a Universe with only 3 or 4 Dimensional States. Our Universe has at a minimum...and there maybe more...10 or 11 Dimensional States. This manny states are need for Quantum Particle/Wave Forms such as Quarks, Glueons, Mesons, Leptons...etc...which are Quanta that completely comprise Protons and Neutrons...thus the Atomic Nucleus of an Atom is actually Quantum Particle/Wave Forms and are completely comprised of Quanta that act as both particle and wave. For Quanta to act as both particle and wave our Universal Reality must have at a minimum 10 or 11 Dimensional States and as well for Quantum Mechanics to even work as it does it is highly likely that a Multiversal System is in play. Dark Energy...the name that has been given to the force that is causing the expansion and acceleration of expansion of our Universe by forcing the Galaxies away from each other...is possibly the result of Divergent Universal States in connection causing Quantum Bleedover between Divergent Universal States specific to one Infinite Universal Grouping of Infinite Groupings in a Multiversal System. Split Infinity -1
MigL Posted March 18, 2013 Posted March 18, 2013 (edited) Don't follow your reasoning, splitinfinity, to put it mildly. Both GR and QFT make do with four dimensions and do an adequate job of explaning reality except for areas where they overlap. I wouldn't say that any more dimensions are necessarily needed. Strimg/M-theory uses 7 compacted dimensions along with the usual four, but its along way from making any verifiable predictions and dark energy is another name for the cosmological constant as a result of vacuum energy Edited March 18, 2013 by MigL
SplitInfinity Posted March 18, 2013 Posted March 18, 2013 Don't follow your reasoning, splitinfinity, to put it mildly. Both GR and QFT make do with four dimensions and do an adequate job of explaning reality except for areas where they overlap. I wouldn't say that any more dimensions are necessarily needed. Strimg/M-theory uses 7 compacted dimensions along with the usual four, but its along way from making any verifiable predictions and dark energy is another name for the cosmological constant as a result of vacuum energy GR and QFT do nothing to explain Quantum Mechanics. Any Universal Model that does not explain Quantum Mechanics is FLAWED. Some Quanta such as Quarks exist at will at and between a numerical minimum and maximum and literally blink in and out of existence. This is not possible using a model with any less than 10 or 11 Dimensional states at a minimum along with a Multiversal System. Split Infinity -1
MigL Posted March 18, 2013 Posted March 18, 2013 Do you know what Quantum Field Theory, QFT, is ? It accounts for your quark/gluon interactions and is known as Quantum Chromodynamics. Look it up.
derek w Posted March 18, 2013 Author Posted March 18, 2013 If hyper volume = volume x time (t) can never = zero,because then (vt) = zero hyper volume so (t) must always be (-t)=(+t) and visa versa volume(xyz) can never = zero,because again (vt) = zero hyper volume If for example you take the plank length as the minimum,PL^3 is the minimum volume and if (t) is infinite,then you have an infinite amount of space piled up along the (t) axis( 4 dimensional string). You also have a minimum for (t),the time it takes to travel one plank length at the speed of light.
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