Thanks Saula...this idea is so good for me....I cannot go in more detail... I would like but I see it so complex...I donīt want to develope TOE...I just want to have a better idea about State of the Art in MQ and GR....to understand better Our Universe.
You say: "by finding groups that contain all the observed symmetries we can unify the forces into one description"...thatīs good...but there we are developing an unifyed model that explain all the forces....but the different forces they exist independent (!!)...or they are only manifestations of a fundamental underlying Global Force?
I mean: We can unifying the model because there are only One Unic Basic and Global Force with different manifestations....or we are jast puting together in the same math model the 4 forces that are independent between them?....or some of them are dependent like weak and EM?
That's why it's called abstract nonsense
Seriously, the general framework in which to understand symmetry groups is category theory, specifically the study of morphisms (symmetry groups are intimately related to automorphisms of structures), which (ie category theory) is at times called "abstract nonsense" (in a fun, non-derogatory way).
Hornblower said: "I don't think anyone denies that gravity is vanishingly weak compared with nuclear forces at extremely short distances, or that the nuclear forces are vanishingly weak compared to gravity at large distances."
Distance of what ?...that is the question....distance is relative to two points...and scale (size) is absolute in one point.
But for me distance is different than scale (size):
One atom has an scale (dimension, size) of aprox 10^-13 meters...The Earth ..10^+7 meters...and galaxy 10^+20 meters
But the distance between them could be very different....it depends on X1-Y1-Z1 vs X2-Y2-Z2 positions
And my opinion is that the correct sentence would say:
"gravity is vanishingly weak compared with nuclear forces at extremely small scales (sizes), or that the nuclear forces are vanishingly weak compared to gravity at large scales (sizes)"."
Nereid....What do you mean with 'background dependent vs background independent' ?....
STARGAZING: All I see are the lights of a billion places I'll never go. --Howard Tayler, Schlock Mercenary
At high enough energies the four forces are thought to be indistinguishable. They will act like one more complex force. Whether that means that they are all low energy manifestations of one force or just that they become impossible to untangle from each other is an open question as I understand it. The motivation of unification theories is basically linked to the first idea, that they are all aspects of one underlying force. But this is the sort of semantic or philosophical distinction I try to avoid. It is believed that one model will describe them all, that is all I am saying. All that means to me is that one model describes them all. I try not to get too caught up in what the maths 'really truly means'.I mean: We can unifying the model because there are only One Unic Basic and Global Force with different manifestations....or we are jast puting together in the same math model the 4 forces that are independent between them?....or some of them are dependent like weak and EM?
It is not just experimental set ups it is because the two properties are genuinely non-commutative. In fact you can measure the two properties for one system fairly precisely using a system of weak measurements, you just cannot do it at once and you need to be very careful to avoid causing the system to decohere.My understanding is that if we measure the position exactly it makes no sense to make a simultaneous exact measurement of momentum. This is because the experimental setups for measuring these variables are fundamentally mutually exclusive (complimentary).
I have very clear the Newton formula....and I know it depends on the mass and distance between objects....
But I am talking about an more abstract concept...that, possibe, it is difficult to understand !!!..
I know that gravity field is different in every space point depending on the distance to nearest mass....and it will be a (vectoriall) sume of them...
But this field will be different at different scales:
- Between galaxies (10^+20 meters)
- Between stars (10^+15 meters), inside a galaxy
- Between planets (10^+10 meters), inside n star
- Between atoms (10^-14 meters), inside a body
Because it is nonsense.
Because the distance is different.But this field will be different at different scales:
- Between galaxies (10^+20 meters)
- Between stars (10^+15 meters), inside a galaxy
- Between planets (10^+10 meters), inside n star
- Between atoms (10^-14 meters), inside a body
Well ...lets go to try to analyse these two sentences:
Hornblower: "anyone denies that gravity is vanishingly weak compared with nuclear forces at extremely short distances, or that the nuclear forces are vanishingly weak compared to gravity at large distances."
Dapifo: "anyone denies that gravity is vanishingly weak compared with nuclear forces at extremely small scales (sizes or dimension), or that the nuclear forces are vanishingly weak compared to gravity at large scales (sizes or dimension)"."
Please, anybody could explain the differences between both, and if both, no one or one of them is the correct????
To use the word "scale" in a scientific context it only makes sense when it is compared to something. Interestingly, the word "scale" does not have an entry in my Oxford concise science dictionary.
The word "size" that you use as in "(sizes or distances)" is completely wrong.
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It is possible that I make an error of language (???)....possibly, for this reason you may not understand it....
By scale I mean a magnitude scale....of size or dimension of space....
Earth is within the scale of 10^+7 meters
Galaxies are within the scale of 10^+20 meters
Atoms are within the scale of 10^-14 meters
Neutrinos are within the scale of 10^-24 meters
If we use the formula Formula G.png and we put the distance, as much large is the distance then weaker is the Force.
The sentence of Hornblower donīt reffer to this formula !!!...he is comparing nuclear and gravity forces at different SCALES !!!! (no distances !!!)
"anyone denies that gravity is vanishingly weak (compared with nuclear forces) at extremely short distances, or that the nuclear forces are vanishingly weak (compared to gravity) at large distances."
I am talking about the gravity field to different scales (dimensions or sizes).
I don't follow you. The nuclear force is strong compared to gravity when looking at a single atom, but gravity is strong compared to the nuclear force for an entire galaxy. There, I said the same thing as Hornblower but worded it with strong instead of weak.
However, this has nothing to do with size. It simply means that gravity is a bit different than the other forces in the sense that it never gets cancelled. It just adds up when you consider more mass/energy. The electric force for earth cancels out. There are the same number of negative charges as positive charges.
Now, is the electromagnetic force weak because I can't measure a net charge for earth? If yes, then why is lightning so strong? Why is the electric force basically zero overall yet we have a magnetic field protecting us. Your concept of weak vs strong will mislead you in trying to answer these questions. The electromagnetic force is considered strong because it has the same formulation as gravity but the constant or 'coupling constant' is bigger than for gravity. That's it. The nuclear force being strong or weak has to do with the fact that it is inverse cube instead of inverse square.
Like everyone else, I wonder what you mean by: scale, strong, weak, and of course 'the state of the art in QM and GR'. Saying the same thing over and over again does not add any clarity to your point.
edit: make note there are plenty of cases where two forces balance each other. Look at the sun. The strong nuclear force makes it 'explode' at the same rate that gravity makes it 'implode'. I can say that they are equal in strength for the entire sun. At this scale, which force is stronger? You can't pin it on size, because stars of different sizes show the same balancing act.
He said distance and he meant distance. Please show, in appropriate mathematical detail, how "scale" is relevant to gravity or the strong nuclear force.
Once again, people are explaining how and why you are wrong. You ignore them and keep repeating that you are right with no basis for your claims.
What you are saying here is what I am trying to explain you all the time !!!...I agree with it!!!...http://cosmoquest.org/forum/showthre...62#post2051062 ....but here you donīt talk about "distance, scale,..." Now you are using another terminology:
- when looking at a single atom,
- for an entire galaxy.
For me here you are talking about bodies, entities, spaces, volums, (sizes, dimensions, scales)....But not DISTANCES !!!
I think that all we are talking about the same...but with different terminology (???)
Only SHAULA understud what i mean!!!!
Last edited by dapifo; 2012-Aug-07 at 09:19 PM.
Essentially I think that what you proposing is that the gauge invariance of the different forces under a dilaton type scaling (one where you can vary the spatial scale factor and the coupling constant in such a way as to preserve the properties of the field) is not valid over all scales. However this introduces issues as the coupling constant relates to the vacuum expectation value of the dilating field's potential. Essentially you would be replacing one field with an infinite series of overlapping fields, a sum over all scales. I would imagine that renormalising this would be brutally hard.
This is too complex for me...
I think that with the following phrases we want to give the same meaning (and I agree with it):
"The nuclear force is strong compared to gravity when looking at a single atom, but gravity is strong compared to the nuclear force for an entire galaxy. There, I said the same thing as Hornblower but worded it with strong instead of weak.."
"gravity is vanishingly weak (compared with nuclear forces) at extremely short distances, or that the nuclear forces are vanishingly weak (compared to gravity) at large distances."
"gravity is vanishingly weak compared with nuclear forces at extremely small scales (sizes or dimension), or that the nuclear forces are vanishingly weak compared to gravity at large scales (sizes or dimension)"."
Although...."distance" and "scale" is not the same concept:
One atom has an scale (dimension, size) of aprox 10^-13 meters...The Earth ..10^+7 meters...and galaxy 10^+20 meters
But the distance between them could be very different....it depends on X1-Y1-Z1 vs X2-Y2-Z2 positions
If the scale isn't the distance the force has to travel, then what is the scale? Or better yet, what is the gauge?
I am guessing that the simplest way to incorporate a scale factor into the equations would be to make the coupling constants functions of distance. But that doesn't work. Just looking at the fine structure constant should make it pretty clear why. I guess you could argue that it is not a continuous function but then you hit the same issues the Standard model has when you try to reconcile it with GR.
In short: The idea doesn't work as far as I can tell and Dapifo, you need to get a far bit more maths and physics under your belt if you want to show me I am wrong. Good luck, but until you have a far more formalised idea I would be wary of trying to get people to agree with you about it. You have no justification or evidence, no reason for anyone to believe in the theory and at first glance it appears incompatible with observations.
Those three sentences already have the same meaning.
What is the meaning of: "Now, is the electromagnetic force weak because I can't measure a net charge for earth? If yes, then why is lightning so strong? Why is the electric force basically zero overall yet we have a magnetic field protecting us. Your concept of weak vs strong will mislead you in trying to answer these questions. The electromagnetic force is considered strong because it has the same formulation as gravity but the constant or 'coupling constant' is bigger than for gravity. That's it. The nuclear force being strong or weak has to do with the fact that it is inverse cube instead of inverse square."
Or even the meaning of: "For a neutron star, which is stronger at any point on the surface: strong nuclear or gravity? What is the scale of the interplay between these forces? Is the strong force not acting as the result of nearby interactions and gravity the result of all that not so nearby mass?"
Feel free to ignore those questions since they would require you to define your ideas.
My bold. The function for the strong nuclear force is vastly steeper than that. See this Wiki article:
http://en.wikipedia.org/wiki/Nuclear_force
According to the author, it is strongly attractive at a separation of about 1 femtometer, but drops to being insignificant beyone about 2.5fm. Inside about 0.7fm it becomes repulsive, setting the characteristic radius of a nucleus or a neutron star as the case may be.
As always, Wiki is not the last word, but my experience has been that they are pretty good on matters like this.
When I was in college, a source whose name I cannot remember roughly approximated that attractive zone as an inverse 9th power, meaning that the attractive force would drop by a about a factor of 1000 in going from 1 to 2fm.
I am puzzled by the recurrence of remarks about "scale" being something distinct from distance. For the purpose of this discussion I think in terms of appropriate units of measurement which in turn are defined in terms of the distance between two suitable reference points. These points could be the centers of adjacent atoms in a crystal, the ends of a meter stick, the centers of the Earth and the Sun, or the centers of two galaxies a megaparsec apart, depending on whether we are analyzing a system on very large scales, very small, or somewhere inbetween. Dapifo keeps on insisting that the Earth, among others, has a "scale" of some number of meters, which appears to be nothing more than the distance between two reference points on opposite sides of it.
What different concept of "scale", if any, is pertinent here? Someone please clarify.