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dapifo
2012-Aug-23, 06:06 PM
Planck length (ℓ P) is the scale or distance of length below which is expected that space stop to have a classical geometry. A measure lower predictably can not be treated adequately in current physics models due to the emergence of quantum gravity effects.

But...There could be energy or/and mass (matter) within the Planck lengh (volum)?.... What is expected by maistream to be within Plank lengh (volum)?

antoniseb
2012-Aug-23, 06:21 PM
... .... What is expected by maistream to be within Plank lengh (volum)?
Officially, there is no expectation within mainstream cosmology as to what is in spaces that small. This domain is hoped to be defined by something that will spring from String/M/Brane Theory, or anything else filling that space, but this is not known or knowable at this time, and any statement about something specific at that scale is speculation, and not mainstream.

Shaula
2012-Aug-23, 06:22 PM
At the Planck length the current mainstream theories do not work adequately because we do not have a theory unifying GR with QM. So it says nothing about mass/energy at scales smaller than the Planck length.

String theory has an interesting duality that renders the concept of lengths smaller than the Planck length meaningless.

Cougar
2012-Aug-23, 06:30 PM
Planck length (ℓ P) is the scale or distance of length below which is expected that space stop to have a classical geometry. A measure lower predictably can not be treated adequately in current physics models due to the emergence of quantum gravity effects.

Well, that's not the only limitation on reliable measurement. The geometry in this regime is expected to be variable and subject to Heisenberg Uncertainty. If the geometry is uncertain, then you cannot determine a metric. With no metric, you can't measure anything.

Reality Check
2012-Aug-24, 01:37 AM
But...There could be energy or/and mass (matter) within the Planck lengh (volum)?.... What is expected by maistream to be within Plank lengh (volum)?
Mainstream particle physics has fundamental particles such as electrons and quarks as point particles (no size). So they will be "within the Planck length". The energy and mass of these particles will be within the Planck length.

dapifo
2012-Aug-24, 03:58 AM
Mainstream particle physics has fundamental particles such as electrons and quarks as point particles (no size). So they will be "within the Planck length". The energy and mass of these particles will be within the Planck length.

My info is that electron and quarks have a dimension of 10^-18 meters...(??)...bigger that the Planck dimension (10^-35 meters)

pzkpfw
2012-Aug-24, 04:09 AM
My info is that electron and quarks have a dimension of 10^-18 meters...(??)...bigger that the Planck dimension (10^-35 meters)

It would help if you noted your source.

Tensor
2012-Aug-24, 06:06 AM
My info is that electron and quarks have a dimension of 10^-18 meters...(??)...bigger that the Planck dimension (10^-35 meters)

This paper (http://arxiv.org/pdf/0810.1420.pdf), from the 34th International Conference on High Energy Physics, gives the UPPER limit on quark size as 6.2-7.4 x 10-19 m. This abstract (http://iopscience.iop.org/1402-4896/1988/T22/016) reports an UPPER limit of 10-22 m for electrons. In reality, elementary particles (such as quarks and electrons) are represented by the wave function in Quantum Field Theory. And particle radius is not part of the information we can extract from the wave function. Essentially, and in the model we use, elementary particles are considered point particles with a zero radius. Experiments indicate that such particles can be treated as point particles.

Shaula
2012-Aug-24, 06:33 AM
The radius you measure also depends on how you measure or define it. I do not believe there is one equivalent 'physical' radius applicable to all interactions. As Tensor says the wavefunction is what is important. Electrons are not little billiard balls.

dapifo
2012-Aug-24, 11:46 AM
Ok...here do you have some orders of magnitude for atomic and sub-atomic particles:

http://en.wikipedia.org/wiki/Orders_of_magnitude_%28length%29#Astronomical

But it does not matter the size of the particles we know .... if we assume the lowest of all (string, banes, neutrinos, preons, ...) ... we can always set a cube of a smaller size (eg 10 ^ -50 meters) and within it must be something.

If this cube is placed inside an electron (or string) .... we allways will have a piece of electron (string) with energy (and mass?) ... although it is not an independent patícula itself.

Shaula
2012-Aug-24, 12:10 PM
Why are you wedded to the idea of a discrete particle? QM has already shown that this is inconsistent with observations. Particles exist as fuzzy quantum objects, not little hard spheres.

As has been said, modern theories break by this scale. We need better ones so the honest answers to your questions are "Don't know". I wouldn't rely on picture based reasoning here, or on 'common sense'. Experience shows that common sense derived from current theory rarely carries over to the next.

dapifo
2012-Aug-24, 12:53 PM
Why are you wedded to the idea of a discrete particle? QM has already shown that this is inconsistent with observations. Particles exist as fuzzy quantum objects, not little hard spheres.

As has been said, modern theories break by this scale. We need better ones so the honest answers to your questions are "Don't know". I wouldn't rely on picture based reasoning here, or on 'common sense'. Experience shows that common sense derived from current theory rarely carries over to the next.

NO....Iīm not talking about a discrete particle..I agree that we donīt know it nowadays...I only reffers to a piece of particle...That sure it musb be (!!?).... and also with a piece of the energy (and mass?) of the whole particle it belongs to (!?)

antoniseb
2012-Aug-24, 01:02 PM
piece of particle[/B]...That sure it musb be (!!?).... ...

Suppose for a moment that such Newtonian concepts as mass, energy, and momentum only make sense in a larger scale, and reflect some statistical side effect of how the next smaller aspects of our universe behave? What you're say doesn't have to be.

dapifo
2012-Aug-24, 02:34 PM
Suppose for a moment that such Newtonian concepts as mass, energy, and momentum only make sense in a larger scale,

I donīt understand what do yo mean?...Are you saying that mass, energy, and momentum ...have only sense in SOME (larger) scales...and that in smaller scale (less than 10^-20 metters?)...they donīt have sense?


....and reflect some statistical side effect of how the next smaller aspects of our universe behave?


Do you mean that mass, energy, and momentum...could be only a reflect of an statistical side effect of smaller aspects of our universe behave?


What you're say doesn't have to be .

What is what doesn't have to be ?...a piece of particle?

Strange
2012-Aug-24, 02:51 PM
we can always set a cube of a smaller size (eg 10 ^ -50 meters) and within it must be something.

Both parts of that are assumptions that may not be valid. It may not be possible to define a cube of a smaller size. And if it is, then there does not need to be "something" within it. I suppose that is a third assumption, that "something" has a meaning at these scales.

Maybe you should read about loop quantum gravity or causal dynamical triangulation. These, and other theories, involve quantising space, so there is a smallest possible size you can subdivide things.

Note that these ideas are "mainstream" (i.e. they are real scientific theories worked on by real scientists) but they are also highly speculative, unproven and may be completely wrong.

ShinAce
2012-Aug-24, 02:56 PM
There are situations where particles exist for me but not for you. Unruh radiation is one of them.

Now tell me, if particles are as real as you or me, why would we need these ghost particles and then virtual particles? How big is a particle that doesn't exist?

dapifo
2012-Aug-24, 03:29 PM
Both parts of that are assumptions that may not be valid. It may not be possible to define a cube of a smaller size.

I find it hard to understand that a very small size .. (10 ^ -50 meters) can not be defined forms and spaces .... mathematics and geometry should not have constraints of scales (!)


And if it is, then there does not need to be "something" within it.

How it is possible to have something (energy or mass) within a size 10^-35 meters...and donīt have any thing a smaller sise inside this place (??)...Does this energy desappear for smaller sizes???


I suppose that is a third assumption, that "something" has a meaning at these scales.

Why not?...Why do you think that there arenīt meaning "anything· at smaller sacales of Planck scale?


Maybe you should read about loop quantum gravity or causal dynamical triangulation. These, and other theories, involve quantising space, so there is a smallest possible size you can subdivide things.

I like very much following statements:

- "At large scales, it re-creates the familiar 4-dimensional spacetime, but it shows spacetime to be 2-d near the Planck scale"
- "at the very smallest scales, space is not static but is instead dynamically-varying"

...It remembers to me "some" theory about scales (?)...and different geometries and laws...(???)...but I donīt remember now were I read it (??)


Note that these ideas are "mainstream" (i.e. they are real scientific theories worked on by real scientists) but they are also highly speculative, unproven and may be completely wrong.

As you say they are also highly speculative, unproven and may be completely wrong theories...

dapifo
2012-Aug-24, 03:30 PM
Now tell me, if particles are as real as you or me, why would we need these ghost particles and then virtual particles? How big is a particle that doesn't exist?

What do you mean?

Strange
2012-Aug-24, 04:03 PM
..It remembers to me "some" theory about scales (?)...and different geometries and laws...(???)...but I donīt remember now were I read it (??)

Which is exactly why I wrote that final sentence: to distinguish these scientific theories from random guesses and wild imaginings.

Tensor
2012-Aug-24, 04:11 PM
I find it hard to understand that a very small size .. (10 ^ -50 meters) can not be defined forms and spaces .... mathematics and geometry should not have constraints of scales (!)

Well, just because you think there shouldn't be constraints, doesn't mean that is the way it is. Can you offer some support showing that math and geometry should not have constraints? For anything smaller than the planck scale, we can't define length,( or area, or volume). At those scales, quantum theory indicates that length is not fixed (not that it ever is, with relativity). Due to the uncertainty principle, how long a length is, depends on what the probability of length being that length.


How it is possible to have something (energy or mass) within a size 10^-35 meters...and donīt have any thing a smaller sise inside this place (??)...Does this energy desappear for smaller sizes???

This is exactly the place where you are having problems. All elementary particles have a probability of being somewhere. Again, due to the uncertainty principle, there is no way to tell for sure where the particle is, so we can't say it it at some location, or falls within some size. That's why I said you can't extract the radius of an elementary particle from it's wave function.


Why not?...Why do you think that there arenīt meaning "anything· at smaller sacales of Planck scale?

Because the very spacetime, used to measure something against, isn't fixed.

You even point this out:


I like very much following statements:

-
- "at the very smallest scales, space is not static but is instead dynamically-varying"

If space is varying, dynamically, then you can't tell how long a length is from one moment to the next. The location of a part of a particle at a point at one moment in time is , may not be the same location (even though the particle stays at that point, at another time, because space is not the same length and the distance has changed at the latter point in time.


As you say they are also highly speculative, unproven and may be completely wrong theories...

They may also be right, unless you know of some information that falsifies those theories, do you? I prefer Loop Quantum Gravity, but Superstring Theory has not been ruled out either.

Shaula
2012-Aug-24, 06:00 PM
I find it hard to understand that a very small size .. (10 ^ -50 meters) can not be defined forms and spaces .... mathematics and geometry should not have constraints of scales
Well one way is in string theory - r is equivalent to 1/r with winding and unwound states swapped. Suggest you read Elegant Universe for a background in this.


NO....Iīm not talking about a discrete particle..I agree that we donīt know it nowadays...I only reffers to a piece of particle..
And I was telling you to forget the particle model. It is not correct.

dapifo
2012-Aug-25, 12:21 AM
Well, just because you think there shouldn't be constraints, doesn't mean that is the way it is. Can you offer some support showing that math and geometry should not have constraints? For anything smaller than the planck scale, we can't define length,( or area, or volume). At those scales, quantum theory indicates that length is not fixed (not that it ever is, with relativity). Due to the uncertainty principle, how long a length is, depends on what the probability of length being that length.


Mainstream says that Laws and geometry must be the same for all the universe scales ....since 10^+(10^1000) till 10^-(10^1000). Other theories are highly speculative, unproven and may be completely wrong.


This is exactly the place where you are having problems. All elementary particles have a probability of being somewhere. Again, due to the uncertainty principle, there is no way to tell for sure where the particle is, so we can't say it it at some location, or falls within some size. That's why I said you can't extract the radius of an elementary particle from it's wave function.

I donīt have any problem...please could you explainme the following:

I have a Volum of Diameter 10^ī35 meters with X energy

If I divide this volumen in 10^10 pieces, I would have 10^10 pieces of X/10^10 energy....Elementary, my dear Tensor...isnīt it?



Because the very spacetime, used to measure something against, isn't fixed.
:


If space is varying, dynamically, then you can't tell how long a length is from one moment to the next. The location of a part of a particle at a point at one moment in time is , may not be the same location (even though the particle stays at that point, at another time, because space is not the same length and the distance has changed at the latter point in time.

I repeat ...Mainstream says that Laws and geometry must be the same for all the universe scales ...What happen with the energy...desapear?....goes to other space-time?....

There are no sense to speak and think in energy and mass...and EM-weak forces...and strong forces...and GR....and QM....and spacī-time?...only 2D?....for these small escales?


They may also be right, unless you know of some information that falsifies those theories, do you? I prefer Loop Quantum Gravity, but Superstring Theory has not been ruled out either.

I donīt....but I see very differents the laws and space-times of small Planck sizes, large Universe sizes, and human Euclide sizes...and it is not possible...because Mainstream says that Laws and geometry must be the same for all the universe sizes.

Something must be wrong !!!

dapifo
2012-Aug-25, 12:25 AM
And I was telling you to forget the particle model. It is not correct.

How is it possible that particle model is not correct for very small dimensions?...Mainstream says that geometry and physics models and laws must be the same for all the universe scales ....Isnīt it?...when models, geometries, laws could be different for different scales?

ShinAce
2012-Aug-25, 12:43 AM
Physics only says that the laws should be the same everywhere, every time. Whether there's a point where the laws simply can't work, no one knows. Even then, if you could prove that that basic tenet of physics is wrong, by experiment, that's fine too. It's just that the simplest answer which explains every known experiment will win.

But, if you want to replace the existing laws, you need that the new idea gives similar answers to the situations we know. Most of the laws I know of are things like: the speed of light in local vacuo is constant, energy is conserved over long periods of time in closed systems, the rules of quantum electrodynamics. QED alone accounts for 99% of our everyday interactions; it's just too complex to use it if you're trying to develop a milder soap. There are plenty of rules out there that give good enough answers depending on what you're doing, but I just don't see where the basic laws change due to scale. Look at Hawking radiation. It's basically the result of applying quantum mechanics to general relativity, with a splash of thermodynamics. If quantum mechanics is only good for the small, and GR only good for the big, why do we have these things called black holes which show that both so called 'laws' apply so well universally?

natattack
2012-Aug-25, 01:18 AM
I think you're confusing the cosmological principle (we don't live in a special time or a special place) with the behaviour of matter and energy at subatomic scales. The former allows us to make predictions about far-off places and times and the latter is, well, rather strange. And even if it's strange, we can make predictions that come true.

It may help to think of it like this. Yes, in a classical way, you can keep mathematically dividing things until you get to 10-50. But that doesn't mean that doing so actually gives you any useful information. You literally can't build a box that small. And there's a difference between treating a particle like a point and it actually being a point.

I second Shaula's suggestion about The Elegant Universe. It discusses the strangeness of quanta as well. Does anyone know if there is an easy way to check what translations may exist for dapifo?

antoniseb
2012-Aug-25, 01:41 AM
Do you mean that mass, energy, and momentum...could be only a reflect of an statistical side effect of smaller aspects of our universe behave?
What is what doesn't have to be ?...a piece of particle?
As a larger scale example of what I mean is the very real laws of thermodynamics which do not apply to small groups of atoms or other particles, but are very reliable when looking at macroscopic quantities of matter. Similarly, there are forces in the nucleus binding protons and neutrons which is really justaside effect of the strong force that holds quarks together.

Others have already suggested this, but you should read a book. You clearly have a great curiosity about all this, but are unusually lacking in the basics, and are working with a large number of misconceptions.

Tensor
2012-Aug-25, 05:08 AM
Well, just because you think there shouldn't be constraints, doesn't mean that is the way it is. Can you offer some support showing that math and geometry should not have constraints? For anything smaller than the planck scale, we can't define length,( or area, or volume). At those scales, quantum theory indicates that length is not fixed (not that it ever is, with relativity). Due to the uncertainty principle, how long a length is, depends on what the probability of length being that length.

Mainstream says that Laws and geometry must be the same for all the universe scales ....since 10^+(10^1000) till 10^-(10^1000).

The laws are the same. But anything smaller than ~1.6 x 10-35 m cannot be measured using our current theories. If you think so, by all means show us in the math of the theories.


Other theories are highly speculative, unproven and may be completely wrong.

Current theories do not work at the Planck Scale and smaller, that you keep trying to say they do, indicates that you do not understand the current theories. Current theories are completely wrong at that scale, BECAUSE THEY DON'T WORK at that scale. And while those new theories may be completely wrong, we don't know that for sure yet. However we do know that our current theories are completely wrong at that scale.


I donīt have any problem...please could you explainme the following:

Yes, you are having a problem. But it is becoming obvious that you don't understand enough of the current theories to realize you have a problem.


I have a Volum of Diameter 10^ī35 meters with X energy

Why didn't you just give the Planck volume of ~4.2 X 10-105 m3?


If I divide this volumen in 10^10 pieces, I would have 10^10 pieces of X/1010 energy....Elementary, my dear Tensor.^..isnīt it?

No, it's not so elementary and it is quite obvious, again, from this statement that you do not understand the actual models we currently use. Energy is photons (I'm ignoring kinetic energy here, since that is frame dependent). You cannot determine the precise location of photons at any scale . If you think so, by all means show us, mathematically, how that is possible. Until then you are doing nothing but arguing against the analogies that explain the concepts simply, not the actual theories. You also have the problem that the concepts of length, area, and volume ARE NOT VALID at those scales. Again, if you believe so, show us, in the math of the different models, where this is possible.


I repeat ...Mainstream says that Laws and geometry must be the same for all the universe scales .

Repeating wrong statements, will not make them correct. Can you show us exactly where the mainstream says the geometry must be the same at all scales? Or for that matter, how our current models are usable at all at those scales.


..What happen with the energy...desapear?....goes to other space-time?....

Who said anything about it disappearing? That is your misunderstanding. Quantum Field Theory says at those scales, you cannot precisely determine where the energy is at. It's all there, we just don't know where exactly. If you disagree, then by all means, show us within Quantum Field Theory that you can determine precisely where the energy is.


There are no sense to speak and think in energy and mass...and EM-weak forces...and strong forces...and GR....and QM....and spacī-time?...only 2D?....for these small escales?

Exactly. Our current models do not work at those scales. And your link did not say spacetime is 2D, it says it approaches 2D. I really don't know where you get the idea that our models work at those scales. Can you point out exactly where in the math of our current models the concept of a volume smaller than ~10-105 is meaningful?



They may also be right, unless you know of some information that falsifies those theories, do you?I donīt....but I see very differents the laws and space-times of small Planck sizes, large Universe sizes, and human Euclide sizes...and it is not possible...because Mainstream says that Laws and geometry must be the same for all the universe sizes.

As I asked, please show us where it says that the geometry must be the same. Can you point out, again mathematically, how the laws are different at different scales?


Something must be wrong !!!

Besides your understanding, it is well known that current QFT (which does not include gravity) and GR do not work well together, at those scales. At least one, and possibly both, will require changes to work at smaller lengths than the Planck Scale.

Shaula
2012-Aug-25, 07:22 AM
How is it possible that particle model is not correct for very small dimensions?...Mainstream says that geometry and physics models and laws must be the same for all the universe scales ....Isnīt it?...when models, geometries, laws could be different for different scales?
Because the particle model is wrong at all scales. It is just a reasonable approximation to the current correct model at largest scales where you can ignore the effects of QM and treat things classically.

I really do suggest that you read Elegant universe. There is a section in that which gives you a mechanism for making 'sub-Planck physics' meaningless.

dapifo
2012-Aug-25, 10:35 AM
Physics only says that the laws should be the same everywhere, every time. Whether there's a point where the laws simply can't work, no one knows.
[...] Look at Hawking radiation. It's basically the result of applying quantum mechanics to general relativity, with a splash of thermodynamics. If quantum mechanics is only good for the small, and GR only good for the big, why do we have these things called black holes which show that both so called 'laws' apply so well universally?

OK....I agree with you....laws should be the same everywhere, every time...and B]Hawking radiation[/B] is a clear example...then why it is not possible to have a volum of 10^-50 meters diameter with energy inside?....why for dimensions smaller than 10^-35 meters....the energy desapears?...what happen with the conservation of the energy law?


I think you're confusing the cosmological principle (we don't live in a special time or a special place) with the behaviour of matter and energy at subatomic scales. The former allows us to make predictions about far-off places and times and the latter is, well, rather strange. And even if it's strange, we can make predictions that come true..

I understand that you are saying that cosmological principle allows us to make predictions about far-off places and times (large scales), and that the behaviour of matter and energy at subatomic scales is different than at large scales?...isnīt it?


It may help to think of it like this. Yes, in a classical way, you can keep mathematically dividing things until you get to 10-50. But that doesn't mean that doing so actually gives you any useful information. You literally can't build a box that small. And there's a difference between treating a particle like a point and it actually being a point.

I know that in a practical way....we (humans) use some small particles (electrons,...) like points....but really they are not...isnīt it.

It may help to think of it like this: For a person (human) who has a dimension of 10^+35 metters ...the Earth could be considered also like a point...but it isnīt...


I second Shaula's suggestion about The Elegant Universe. It discusses the strangeness of quanta as well. Does anyone know if there is an easy way to check what translations may exist for dapifo?

I have read several QM books....but Iīll try to read also The Elegant Universe...thanks.


As a larger scale example of what I mean is the very real laws of thermodynamics which do not apply to small groups of atoms or other particles, but are very reliable when looking at macroscopic quantities of matter. Similarly, there are forces in the nucleus binding protons and neutrons which is really justaside effect of the strong force that holds quarks together.
.

Are you saying that physics have different behaviour (laws) at different scales?...is it possible?....I think that Shaula and Strange donīt agree with it !!!

dapifo
2012-Aug-25, 10:54 AM
The laws are the same. But anything smaller than ~1.6 x 10-35 m cannot be measured using our current theories.

Current theories do not work at the Planck Scale and smaller,{...]. Current theories are completely wrong at that scale, BECAUSE THEY DON'T WORK at that scale. And while those new theories may be completely wrong, we don't know that for sure yet. However we do know that our current theories are completely wrong at that scale.

[...] Energy is photons (I'm ignoring kinetic energy here, since that is frame dependent). You cannot determine the precise location of photons at any scale . [...] You also have the problem that the concepts of length, area, and volume ARE NOT VALID at those scales. {...}

Can you show us exactly where the mainstream says the geometry must be the same at all scales? Or for that matter, how our current models are usable at all at those scales.

Who said anything about it disappearing? That is your misunderstanding. Quantum Field Theory says at those scales, you cannot precisely determine where the energy is at. It's all there, we just don't know where exactly. If you disagree, then by all means, show us within Quantum Field Theory that you can determine precisely where the energy is.

Exactly. Our current models do not work at those scales. And your link did not say spacetime is 2D, it says it approaches 2D. I really don't know where you get the idea that our models work at those scales. Can you point out exactly where in the math of our current models the concept of a volume smaller than ~10-105 is meaningful?

As I asked, please show us where it says that the geometry must be the same. Can you point out, again mathematically, how the laws are different at different scales?

Besides your understanding, it is well known that current QFT (which does not include gravity) and GR do not work well together, at those scales. At least one, and possibly both, will require changes to work at smaller lengths than the Planck Scale.

Can you point out, again mathematically, how the laws are different at different scales?: Tensor...if you read what you said beffore... You are answering this question !!!

I realize that science has developed different models (maths, physics,...) for diferent scales to try to explain its behavour at these different dimensions...isnīt it?

What is a law?...A Law it is just a function valid for a Model !!!...isnīt it?... Well I donīt know what do you mean by law....possibly it is a lamguage problem...for me a (maths or physics) law is only a function that explain a behavour into a determinated model (!!?)

Shaula
2012-Aug-25, 11:07 AM
Are you saying that physics have different behaviour (laws) at different scales?...is it possible?....
The underlying laws are the same, the approximations we use to make solving the problems change with a numebr of things, from physical scale to number of entities involved.

What you seem to be missing is this: The underlying laws of QED/QCD/GR and so on are the (currently understood) fundamental laws. They apply at ALL scales we can model. However when dealing with a box full of atoms it is simply too hard to work out a full quantum mechanical treatment. So we have models like gas laws, thermodynamics and so on that work for these systems.


OK....I agree with you....laws should be the same everywhere, every time...and B]Hawking radiation[/B] is a clear example...then why it is not possible to have a volum of 10^-50 meters diameter with energy inside?....why for dimensions smaller than 10^-35 meters....the energy desapears?...what happen with the conservation of the energy law?
Go read the book. The full explanation as to how talking about sizes smaller than a Planck length takes a chapter or so. Too much to try to post up here. It may not be the right model, but it explains one way that might mean your question makes no sense.

dapifo
2012-Aug-25, 11:07 AM
Because the particle model is wrong at all scales. It is just a reasonable approximation to the current correct model at largest scales where you can ignore the effects of QM and treat things classically.

I really do suggest that you read Elegant universe. There is a section in that which gives you a mechanism for making 'sub-Planck physics' meaningless.

Are yuo saying that the particle model is only a model to explain in an approximity way current correct model at largest scales ?...then I agree with you !!!....I new it!!!

As I also think that our model for the QM is only a model to explain in an approximity way current correct model at smallest scales... and that both models are differents..although we could bild a Whole Model (M-Theory) that join both....but this (M-Theory) will be only another model (wider) to explain in an approximity way current correct model at widest scales.

Shaula
2012-Aug-25, 11:17 AM
Are yuo saying that the particle model is only a model to explain in an approximity way current correct model at largest scales ?...then I agree with you !!!....I new it!!!
No. I am not. I am saying that the particle model is an approximation. At all scales, from smallest to largest. It works for some things, not for others.

I have given you many, many reasons that is would be a good idea to do some background reading before going on yet again about scales and different physics at different scales. I am simply not interested in approaching this topic from yet another angle. You are not upholding your side of the deal: I try to reply helpfully to your questions and in return you listen and try to do more research and background reading. Instead this looks like another attempt to get your ideas validated

dapifo
2012-Aug-25, 11:17 AM
The underlying laws are the same, the approximations we use to make solving the problems change with a numebr of things, from physical scale to number of entities involved.

What you seem to be missing is this: The underlying laws of QED/QCD/GR and so on are the (currently understood) fundamental laws. They apply at ALL scales we can model. However when dealing with a box full of atoms it is simply too hard to work out a full quantum mechanical treatment. So we have models like gas laws, thermodynamics and so on that work for these systems.

OK...OK...OK...I agree with you !!!!!!

Then I had an languadge misunderstanding !!!!...it is clear that The underlying laws of the nature and the whole universe are the same !!!

But we (humans..and scientifics) had to develope different models for explaying its functioning at different scales....that is what I was trying to say all the time !!!!...but I cofuse the meaning of LAWS with MODELS !!!!!

So, I had to say that: "Maths and physics models are different for different scales...although the physics underlaying laws are the same for all the scales of the Whole Universe!!!"

Shaula
2012-Aug-25, 11:30 AM
The fact that we use different sets of approximations for different scales (physical, levels of complexity) and different environments is just a basic fact of every science. When we are doing population studies in biology we do not model every genetic interaction in the herd. When designing a wing for a plane we do not model every atom of air and metal.

dapifo
2012-Aug-25, 12:12 PM
The fact that we use different sets of approximations for different scales (physical, levels of complexity) and different environments is just a basic fact of every science. When we are doing population studies in biology we do not model every genetic interaction in the herd. When designing a wing for a plane we do not model every atom of air and metal.

This is clear....I always said that we develope a model to explain Our Universe... that has been going growing up with the years and widen the scale range.

And matter is just a model to explain our near spectrum we live... but that matter as we know really doesnīt exist...but explain very well Our Near Universe.

If we could make ourselves as small as an electron, the model that we would build there about these small scale universe (10^-20 meters) would be totally different from current Near Spectrum (scale) we live now (10^0 meters), but I also believe it would also be different from that we have developed for these scales as small (QM).

QM is a "good" theory to explain small scales physics behaviour,, from the point of view of Our Scale....but this model could be absolutlly different if we could puzzle out it if we could make ourselves as small as an electron....

Sure that there (at these scales) we would be able to develope another model...more understable were I donīt have clear that some current mainstream theories would be valid there (pe. uncertainty principle?)....and possibly also it will be more undestable what is happening in smaller scales (less than 10^-35 meters)....although it will be very confusing to try to understand what is happening to Our Current Scale (current human scale=10*0 meters)... and possibly imposible to understand what is happening to larger scales (larger than 10^+20 meters).

Do you understand what I mean now?...do you understand my sign now?[/

Shaula
2012-Aug-25, 01:05 PM
You seem to be making a huge deal out of the fact that there are models suitable for a range of different approximations (large spatial distances, low energies, few interacting components and many others). Yes - we know. We have models that work at a huge range of scales. We understand their limits and their usefulness.

dapifo
2012-Aug-25, 02:32 PM
You seem to be making a huge deal out of the fact that there are models suitable for a range of different approximations (large spatial distances, low energies, few interacting components and many others). Yes - we know. We have models that work at a huge range of scales. We understand their limits and their usefulness.

OK...I can now breathe easy ...I was really worried that something so obvious and evident was an ATM (!) .... and that it would cost so much to understand (!!)

But sometimes experts are so happy and satisfied with the existing models that they become too dogmatic and categorical with its contents and statements....and sometimes they forget that they are only models suitable for a range of different approximations and they forget their limits and their usefulness.

I never said that this was a new idea...and I never make huge deal out with it....but yes I tryed to state these limits and their usefulness.

Strange
2012-Aug-25, 02:34 PM
I have a Volum of Diameter 10^ī35 meters with X energy

If I divide this volumen in 10^10 pieces, I would have 10^10 pieces of X/1010 energy....

I think this has been well answered already but...

Pperhaps you can think of it this way (ignoring whether it is possible or not): energy is quantised, therefore you cannot have half a photon or half an electron. All you do by changing the volume, is change the probability that the photon (or whatever) is in that volume at any time.

p.s. And please stop with the excessive exclamation marks. It doesn't help your argument.

dapifo
2012-Aug-25, 02:54 PM
I think this has been well answered already but...

Pperhaps you can think of it this way (ignoring whether it is possible or not): energy is quantised, therefore you cannot have half a photon or half an electron. All you do by changing the volume, is change the probability that the photon (or whatever) is in that volume at any time.

p.s. And please stop with the excessive exclamation marks. It doesn't help your argument.

Ok...now it is more clear....as much smaller be the volume...less probabilities there are that a photon or an electron will be there.

The photons could be so small as the EM waves that transport to them....Could photons be smaller than 10^-35 meters?

Escuss the exclamation marks....but I though they make the discussion more real and lively...Without marks, bolds, colors...it is so boring and sad (!!)

dapifo
2012-Aug-25, 02:56 PM
What does mainstream says about the time at these small dimensions?...Does there exist the time as we know here?

natattack
2012-Aug-25, 03:30 PM
[snip]
Escuss the exclamation marks....but I though they make the discussion more real and lively...Without marks, bolds, colors...it is so boring and sad (!!)

As an aside, shouting doesn't make your argument any more eloquent. Multiple exclamation marks makes text come out as a "wail", in my opinion. Excessive use of punctuation marks deadens the effect. They should be used sparingly. Excessive punctuations marks, bolds, italics, etc. also distract from a text and prevent real communication. If you find the content boring, perhaps you should ask yourself why you are here?

dapifo
2012-Aug-25, 03:40 PM
As an aside, shouting doesn't make your argument any more eloquent. Multiple exclamation marks makes text come out as a "wail", in my opinion. Excessive use of punctuation marks deadens the effect. They should be used sparingly. Excessive punctuations marks, bolds, italics, etc. also distract from a text and prevent real communication. If you find the content boring, perhaps you should ask yourself why you are here?

I see that you are an expert in forums and chad languadge...I am not !!....I like to talk, if it is possible, directly...and with a blak/whiteboard with colors chalk/markers....and jocking if possible.

The boring is to be writen at an pc....

antoniseb
2012-Aug-25, 05:34 PM
What does mainstream says about the time at these small dimensions?...Does there exist the time as we know here?
Mainstream says nothing about this. Did you read any of the recommended books yet?
Side note, if you think that all of the other posters with their non-bolded or underlined, uncolored, correctly spelled text are boring, it would be polite to keep it to yourself.

Hornblower
2012-Aug-25, 06:46 PM
OK...I can now breathe easy ...I was really worried that something so obvious and evident was an ATM (!) .... and that it would cost so much to understand (!!)

But sometimes experts are so happy and satisfied with the existing models that they become too dogmatic and categorical with its contents and statements....and sometimes they forget that they are only models suitable for a range of different approximations and they forget their limits and their usefulness.I never said that this was a new idea...and I never make huge deal out with it....but yes I tryed to state these limits and their usefulness.

My bold. Can you give us some specific examples?

korjik
2012-Aug-25, 06:53 PM
OK...I can now breathe easy ...I was really worried that something so obvious and evident was an ATM (!) .... and that it would cost so much to understand (!!)

I know I said that atleast twice already. Good to know you are finally understanding


But sometimes experts are so happy and satisfied with the existing models that they become too dogmatic and categorical with its contents and statements....and sometimes they forget that they are only models suitable for a range of different approximations and they forget their limits and their usefulness.

Incorrect and insulting. Good job.


I never said that this was a new idea...and I never make huge deal out with it....but yes I tryed to state these limits and their usefulness.

You have been making a big deal out of it in at least three threads. You were told repeatedly that it was nothing, yet, because actual scientists are 'too dogmatic and categorical' you would not accept the answer. Perhaps the problem is not with the scientists.

dapifo
2012-Aug-25, 08:31 PM
Mainstream says nothing about this. Did you read any of the recommended books yet?
Side note, if you think that all of the other posters with their non-bolded or underlined, uncolored, correctly spelled text are boring, it would be polite to keep it to yourself.

Sure I will do....

No, I donīt thik so.... but I like it !!!.... It is my sign...!!!But if this is forbidden .... I stop! ....You are free to do the best you think !!

dapifo
2012-Aug-25, 08:39 PM
My bold. Can you give us some specific examples?

e.g. To say very dogmatic and categorical that the light speed is the max. speed that could be.

We have to think (but not necessary to say always...but...have into account !!!)...that it is true ...till we know nowadays...in Our universe...according mainstream...etc.

dapifo
2012-Aug-25, 08:41 PM
I know I said that atleast twice already. Good to know you are finally understanding

Incorrect and insulting. Good job.


You have been making a big deal out of it in at least three threads. You were told repeatedly that it was nothing, yet, because actual scientists are 'too dogmatic and categorical' you would not accept the answer. Perhaps the problem is not with the scientists.

OK..it is my fault....but I didnīt insult any body.

onomatomanic
2012-Aug-25, 09:34 PM
But sometimes experts are so happy and satisfied with the existing models that they become too dogmatic and categorical with its contents and statements....and sometimes they forget that they are only models suitable for a range of different approximations and they forget their limits and their usefulness.


This claim doesn't really make sense, because the more recent models themselves indicate that they break down in certain contexts. Older models, typically, did not.

For example, Newtonian mechanics is simply wrong, from a purist's point of view. It doesn't contain any indications that it will break down near the speed of light, yet we know this to be the case. The only reason we still use it is that it is a delightfully simple model that makes delightfully good predictions as long as you don't go near the speed of light. And in the less pure modern understanding of how models relate to reality, that pretty much makes it true despite what the purist may think.

Quantum mechanics (and, by extension, anything that derives from it), on the other hand, tells you right off the bat that it's not going to be able to make any sort of usable predictions under certain conditions, at certain scales, for certain classes of phenomena, and so on. So, no matter how "dogmatic and categorical" an expert may be, they aren't going to make any claims to the contrary. If they do, then they are by definition not experts.

dapifo
2012-Aug-25, 09:41 PM
This claim doesn't really make sense, because the more recent models themselves indicate that they break down in certain contexts. Older models, typically, did not.

For example, Newtonian mechanics is simply wrong, from a purist's point of view. It doesn't contain any indications that it will break down near the speed of light, yet we know this to be the case. The only reason we still use it is that it is a delightfully simple model that makes delightfully good predictions as long as you don't go near the speed of light. And in the less pure modern understanding of how models relate to reality, that pretty much makes it true despite what the purist may think.

Quantum mechanics (and, by extension, anything that derives from it), on the other hand, tells you right off the bat that it's not going to be able to make any sort of usable predictions under certain conditions, at certain scales, for certain classes of phenomena, and so on. So, no matter how "dogmatic and categorical" an expert may be, they aren't going to make any claims to the contrary. If they do, then they are by definition not experts.

That is why I said ... sometimes.

Strange
2012-Aug-25, 11:05 PM
e.g. To say very dogmatic and categorical that the light speed is the max. speed that could be.

Dogma suggests something is a matter of belief. The idea that the speed of light is a limit is a result of a well-tested theory. It isn't dogma to state this, it is just a statement of our current best theory. It may be that a future theory will change this. Or maybe not. Until it is demonstrated to be false all the evidence is that nothing can go faster than light.

Did you notice the key words there: theory, evidence? Not dogma.

Shaula
2012-Aug-26, 12:51 AM
e.g. To say very dogmatic and categorical that the light speed is the max. speed that could be.
Do you understand why people say this with such certainty?

dapifo
2012-Aug-26, 01:39 AM
Do you understand why people say this with such certainty?

Why?

antoniseb
2012-Aug-26, 06:39 AM
... Are you saying that physics have different behaviour (laws) at different scales?...is it possible?....I think that Shaula and Strange donīt agree with it !!!
OK, Now you are clearly trolling. Goodbye.

Shaula
2012-Aug-26, 07:40 AM
Why?
Suggest you do some background reading about GR and SR. Your stance is pretty weak - you are essentially saying "These guys believe this fact dogmatically. No I have no idea why, or what the background is. I just know they believe it. Dogmatically." In fact one could say that you have a dogmatic believe in the dogmatism of scientists.

VonBelmont
2012-Sep-09, 07:06 AM
Planck length (ℓ P) is the scale or distance of length below which is expected that space stop to have a classical geometry. A measure lower predictably can not be treated adequately in current physics models due to the emergence of quantum gravity effects.

But...There could be energy or/and mass (matter) within the Planck lengh (volum)?.... What is expected by maistream to be within Plank lengh (volum)?

We might expect a class of exotic particles, called Planck Particles. I have been doing investigations on this subject myself. This particle is roughly the size of a Planck Length.