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Author Topic: What will fit in a Planck volume?  (Read 7783 times)

Offline jeffreyH

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What will fit in a Planck volume?
« on: 08/10/2013 08:08:32 »
The question I want to ask is this, is there a minimum and maximum mass-energy density that will fit into a planck volume?
« Last Edit: 09/10/2013 09:42:55 by chris »


 

Offline Pmb

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Re: What will fit in a planck volume
« Reply #1 on: 08/10/2013 14:27:22 »
The question I want to ask is this, is there a minimum and maximum mass-energy density that will fit into a planck volume?
This is bizzare stuff. I don't think there are real answers to be found since there is no universally accepted theory of quantum gravity. E.g. an electron is a point particle and therefore it's entirety should fit at a point even though its mass density is infinite there.
 

Offline jeffreyH

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Re: What will fit in a planck volume
« Reply #2 on: 08/10/2013 14:37:53 »
The question I want to ask is this, is there a minimum and maximum mass-energy density that will fit into a planck volume?
This is bizzare stuff. I don't think there are real answers to be found since there is no universally accepted theory of quantum gravity. E.g. an electron is a point particle and therefore it's entirety should fit at a point even though its mass density is infinite there.

This appears to be the crux of the matter. To explain singularities we need to establish what these limits are likely to be. We may find that the answer either supports or rejects the idea of a singularity. Until we can establish answers to these sorts of questions we can never unify everything.
 

Offline Pmb

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Re: What will fit in a planck volume
« Reply #3 on: 08/10/2013 14:47:57 »
The question I want to ask is this, is there a minimum and maximum mass-energy density that will fit into a planck volume?
This is bizzare stuff. I don't think there are real answers to be found since there is no universally accepted theory of quantum gravity. E.g. an electron is a point particle and therefore it's entirety should fit at a point even though its mass density is infinite there.

This appears to be the crux of the matter. To explain singularities we need to establish what these limits are likely to be. We may find that the answer either supports or rejects the idea of a singularity. Until we can establish answers to these sorts of questions we can never unify everything.

A proper understanding of uncertainty comes with understanding what that term means. It must be kept in mind and never forgotten that it does not apply to single, individual measurements. Uncertainty is defined in terms of statistical variation and that only applies to large numbers of measurements on identically prepared systems. So there's nothing wrong with saying that an electron can't be considered to be within any finite volume of space.
 

Offline jeffreyH

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Re: What will fit in a planck volume
« Reply #4 on: 08/10/2013 15:11:14 »
The question I want to ask is this, is there a minimum and maximum mass-energy density that will fit into a planck volume?
This is bizzare stuff. I don't think there are real answers to be found since there is no universally accepted theory of quantum gravity. E.g. an electron is a point particle and therefore it's entirety should fit at a point even though its mass density is infinite there.

This appears to be the crux of the matter. To explain singularities we need to establish what these limits are likely to be. We may find that the answer either supports or rejects the idea of a singularity. Until we can establish answers to these sorts of questions we can never unify everything.

A proper understanding of uncertainty comes with understanding what that term means. It must be kept in mind and never forgotten that it does not apply to single, individual measurements. Uncertainty is defined in terms of statistical variation and that only applies to large numbers of measurements on identically prepared systems. So there's nothing wrong with saying that an electron can't be considered to be within any finite volume of space.

I totally agree with that point. The question can be formulated as to whether or not length contraction goes all the way down to the planck scale. If it does then as mass contracts so do quantum scales of spacetime so that no real effective density accumulates at that scale. In which case singularities are possible. If the planck scale is invariant then a reconsideration of relativity must be applied.

Another point to consider is whether you still get zero gravity at the centre of a collapsed mass.
« Last Edit: 08/10/2013 15:14:46 by jeffreyH »
 

Offline Phractality

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Re: What will fit in a planck volume
« Reply #5 on: 08/10/2013 22:11:06 »
If the universe is fractal, you have a whole 'nother universe inside every Planck volume. But that is new theory, not standard physics. Nothing in OUR universe can fit in a Planck volume. A photon having a wavelength that short would have so much energy that it would be a black hole, assuming that the energy to wavelength formula holds at that scale.
 

Offline jeffreyH

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Re: What will fit in a planck volume
« Reply #6 on: 08/10/2013 23:06:24 »
If the universe is fractal, you have a whole 'nother universe inside every Planck volume. But that is new theory, not standard physics. Nothing in OUR universe can fit in a Planck volume. A photon having a wavelength that short would have so much energy that it would be a black hole, assuming that the energy to wavelength formula holds at that scale.

This is the exact issue. If nothing in our universe can fit in a Planck volume then it must contract to preserve this assumption. In that case it could be that the frozen gravitation and the frozen contraction hold the system of a black hole together. As the granular level of the universe is at the Planck scale the whole system is elastic down to the microscopic level.
 

Offline jeffreyH

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Re: What will fit in a planck volume
« Reply #7 on: 08/10/2013 23:18:07 »
 

Offline Pmb

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Re: What will fit in a planck volume
« Reply #8 on: 09/10/2013 04:50:23 »
Quote from: Phractality
A photon having a wavelength that short would have so much energy that it would be a black hole, ...
That is not possible. No photon can be a black hole. This is easy to see. Consider a photon in frame S having energy E. Now transform to frame S' moving relative to S with such a speed that the photons energy as measured in that frame will be so large as to fullfill the condition of the Schwarzschild mass fitting inside the Schwarschild horizon. Since the existance of photons is not frame dependant you can easily see that no photon can have enough energy to form a black hole.
« Last Edit: 09/10/2013 04:52:55 by Pmb »
 

Offline jeffreyH

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Re: What will fit in a planck volume
« Reply #9 on: 09/10/2013 17:30:28 »
Quote from: Phractality
A photon having a wavelength that short would have so much energy that it would be a black hole, ...
That is not possible. No photon can be a black hole. This is easy to see. Consider a photon in frame S having energy E. Now transform to frame S' moving relative to S with such a speed that the photons energy as measured in that frame will be so large as to fullfill the condition of the Schwarzschild mass fitting inside the Schwarschild horizon. Since the existance of photons is not frame dependant you can easily see that no photon can have enough energy to form a black hole.

I'm just trying to get my head round what the dimensions of the Schwarzschild radius would be for a photon.
 

Offline yor_on

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Re: What will fit in a Planck volume?
« Reply #10 on: 13/10/2013 02:14:37 »
If you find that one you also should have the 'size' of that photon :)
 

Offline jeffreyH

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Re: What will fit in a Planck volume?
« Reply #11 on: 13/10/2013 03:20:30 »
If you find that one you also should have the 'size' of that photon :)

And we could sell the concept to Disney.
 

Offline jeffreyH

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Re: What will fit in a Planck volume?
« Reply #12 on: 13/10/2013 07:20:23 »
There are several points that need to be addressed. 1. Is the Planck scale invariant so that it is unchanging while the rest of spacetime curves? 2. If it is invariant then what we call spacetime slides around over this scale and compression will result in variable densities within each Planck volume. 3. If Planck units expand or contract it could either be that variable densities could occur regardless of these changes or density is constant. 4. If density is fixed then the expansion or contraction at the Planck scale could result in a time dilation effect based upon the distortion. 5. If both Planck dimension and density are variable then the singularity would no longer be at infinity as we understand it, as this progression could go on indefinitely.
 

Offline Pmb

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Re: What will fit in a Planck volume?
« Reply #13 on: 13/10/2013 07:24:36 »
Quote from: jeffreyH
1. Is the Planck scale invariant
Yes.

The rest weren't questions or things to be determined.
 

Offline jeffreyH

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Re: What will fit in a Planck volume?
« Reply #14 on: 13/10/2013 10:47:25 »
Quote from: jeffreyH
1. Is the Planck scale invariant
Yes.

The rest weren't questions or things to be determined.

So it is determined that 1 Planck length in reference frame A will measure the same from reference frame B.

Take a length that is 1000000 Planck lengths in frame A, length contract it by 20%, how many Planck lengths would it now measure from frame B, and why?
« Last Edit: 13/10/2013 10:57:11 by jeffreyH »
 

Offline yor_on

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Re: What will fit in a Planck volume?
« Reply #15 on: 13/10/2013 14:19:49 »
That is a interesting question Jeffery, but it presumes a common for us all universe in where we can expect observer dependencies to disappear. Whatever you measure on will be locally, and there we should find that we agree on units, just as we can find 'repeatable experiment'. So locally defined (measured) those units makes sense, and must be found the same for us all. To get to your question you first need to define at what imaginary/theoretical plane we can find this 'common universe' in where your question can be asked. Once you have done that it will make sense. The closest I know to such a universe should then be at that same place where Lorentz transformations rests. But I don't see how that could be defined as a SpaceTime/continuum in its own right.

A local experiment is the ground for a repeatable experiment.
Several local 'identical' experiments, so becoming repeatable in giving us a same answer, is the ground for a 'common universe', governed by 'global rules'.

And there is no way I know of to measure any other way than locally. What you then can do is to take local measurements and try to find some common nominator for why and how they differ, that's a Lorentz transformation and 'c'.
 

Offline jeffreyH

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Re: What will fit in a Planck volume?
« Reply #16 on: 14/10/2013 05:43:55 »
That is a interesting question Jeffery, but it presumes a common for us all universe in where we can expect observer dependencies to disappear. Whatever you measure on will be locally, and there we should find that we agree on units, just as we can find 'repeatable experiment'. So locally defined (measured) those units makes sense, and must be found the same for us all. To get to your question you first need to define at what imaginary/theoretical plane we can find this 'common universe' in where your question can be asked. Once you have done that it will make sense. The closest I know to such a universe should then be at that same place where Lorentz transformations rests. But I don't see how that could be defined as a SpaceTime/continuum in its own right.

A local experiment is the ground for a repeatable experiment.
Several local 'identical' experiments, so becoming repeatable in giving us a same answer, is the ground for a 'common universe', governed by 'global rules'.

And there is no way I know of to measure any other way than locally. What you then can do is to take local measurements and try to find some common nominator for why and how they differ, that's a Lorentz transformation and 'c'.

If Planck scale is length contracted light speed would still remain constant for all observers. The distorted spacetime would still be local for the observer at that point and still give all the correct measurements.
 

Offline yor_on

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Re: What will fit in a Planck volume?
« Reply #17 on: 14/10/2013 15:45:31 »
Then you're applying a global perspective on it, right? like a universe consisting of distorted fishbowls in where you locally always will find 'c', although from some theoretical plane observing that they all are different? That one is not possible to me. What is correct to me is that 'c' is what you always will measure, although you can argue that a acceleration will differ, as well as light paths through gas and solids also will differ. There is no global definition from where you can watch such a thing.

When you measure a time dilation/Lorentz contraction you use your wristwatch. that wristwatch can loosely be defined as being your 'local time keeper'. This statement is as true for you as for me, including all points in a universe when measured from. Wherever you are your local time will be the same, relative what matters locally, as your life span, and it is that time device you use as a anchor for your measurements over frames of reference.

You define a time dilation comparing between your local frame and some other, There is no 'set frame' defining what a 'correct time' is, except your local definition. Locally you can define that one as set though, although depending on how you define what 'locally' should mean under the circumstances. There are two ways, one is being macroscopically 'at rest' with something, as we are at rest with Earth sleeping, the other is stricter, and as I see it ultimately demands a superposition of identical particles, to become a ideal definition of what being at rest with 'something' might mean.

But the key point is that there is no frame being more right than the other, from a 'global perspective', as in a 'commonly shared by us all SpaceTime'. It's only if you define it locally you will find yourself having a 'set time', and that set time is the same at a neutron star as it is on Earth, locally defined.
 

Offline yor_on

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Re: What will fit in a Planck volume?
« Reply #18 on: 14/10/2013 15:55:51 »
Another way to look at it is from the aspects of mass and speeds. Depending on your speed and mass you will see different fishbowls, measuring over frames of reference. there are no set definitions, except a strictly local using that 'wrist watch', in the same way as 'c' always is a local definition.
 

Offline jeffreyH

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Re: What will fit in a Planck volume?
« Reply #19 on: 19/10/2013 01:50:06 »
Another way to look at it is from the aspects of mass and speeds. Depending on your speed and mass you will see different fishbowls, measuring over frames of reference. there are no set definitions, except a strictly local using that 'wrist watch', in the same way as 'c' always is a local definition.

Locality is the limiting factor which we can't easily get round. To sort out what gravity is we are going to have to find a different way to view the universe.
 

Offline HorrorToTheMax

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Re: What will fit in a Planck volume?
« Reply #20 on: 22/10/2013 20:27:23 »
I don't think anything could fit in a plank lenth since it is the smallest thing in the universe but there must be at least 1 thing in the universe that could fit in it beacuse there is no proof of the plank lenth being the smallest thing so there could be somthing that could fit in it or something even smaller!
« Last Edit: 22/10/2013 20:29:32 by HorrorToTheMax »
 

Offline jeffreyH

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Re: What will fit in a Planck volume?
« Reply #21 on: 27/10/2013 18:48:42 »
Then you're applying a global perspective on it, right? like a universe consisting of distorted fishbowls in where you locally always will find 'c', although from some theoretical plane observing that they all are different? That one is not possible to me. What is correct to me is that 'c' is what you always will measure, although you can argue that a acceleration will differ, as well as light paths through gas and solids also will differ. There is no global definition from where you can watch such a thing.

When you measure a time dilation/Lorentz contraction you use your wristwatch. that wristwatch can loosely be defined as being your 'local time keeper'. This statement is as true for you as for me, including all points in a universe when measured from. Wherever you are your local time will be the same, relative what matters locally, as your life span, and it is that time device you use as a anchor for your measurements over frames of reference.

You define a time dilation comparing between your local frame and some other, There is no 'set frame' defining what a 'correct time' is, except your local definition. Locally you can define that one as set though, although depending on how you define what 'locally' should mean under the circumstances. There are two ways, one is being macroscopically 'at rest' with something, as we are at rest with Earth sleeping, the other is stricter, and as I see it ultimately demands a superposition of identical particles, to become a ideal definition of what being at rest with 'something' might mean.

But the key point is that there is no frame being more right than the other, from a 'global perspective', as in a 'commonly shared by us all SpaceTime'. It's only if you define it locally you will find yourself having a 'set time', and that set time is the same at a neutron star as it is on Earth, locally defined.

Light describes the universal reference frame. It has to travel from point A to point B at exactly c. Points A and point B are fixed points in spacetime. Where ever you are there will always be those fixed points.
 

Offline yor_on

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Re: What will fit in a Planck volume?
« Reply #22 on: 08/11/2013 13:16:38 »
Depends on definitions Jeffery. point A to B is indeed a 'fixed' reference, defining 'fixed points', relative me measuring. Introduce point C, traveling at some speed (relative light, blue shifting it) or ignoring that, relative point A, assuming that would be me. Then you will have two definitions of the distance between A and B. Mine being A, yours being C, both measuring getting valid answers. The rest is Lorentz transformations.
 

Offline jeffreyH

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Re: What will fit in a Planck volume?
« Reply #23 on: 11/11/2013 23:19:47 »
Depends on definitions Jeffery. point A to B is indeed a 'fixed' reference, defining 'fixed points', relative me measuring. Introduce point C, traveling at some speed (relative light, blue shifting it) or ignoring that, relative point A, assuming that would be me. Then you will have two definitions of the distance between A and B. Mine being A, yours being C, both measuring getting valid answers. The rest is Lorentz transformations.

Einstein proposed spacetime curvature but this is surely spacetime compression as defined by the singularity. No one as yet has tackled the the separate spheres argument posted in my thread on mass-energy density and gravitational field strength. The inter-molecular interactions and especially the bonds holding solids together appear to have an appreciable effect of overall gravitation. This links gravitation directly to the atomic and molecular scales. In this view we could consider the earth or any other celestial body as one single large solid. If it were simply discrete parts hanging together in space my own view is that even though the mass may be the same the gravitation would be much reduced. No matter how densely the components were packed. This is because they do not interact at the molecular level as a single solid body.
 

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Re: What will fit in a Planck volume?
« Reply #23 on: 11/11/2013 23:19:47 »

 

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