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## Why is the strong Nuclear force the strongest?

1kg of copper, without electrons, would accelerate a copper nucleus in a distance of 10cm with an acceleration of about 1027 m/s2, reaching ultrarelativistic speeds within less than a nanometer (neglecting the finite propagation time of the electromagnetic force here). The total energy content in the electrostatic repulsion would be 1 billion times the rest energy of the copper block and equivalent to the total energy radiated by the sun in ~1/4 seconds. This corresponds to 50 billion megatons of TNT - one billion times the yield of the strongest bomb ever built, and more than 100 times the energy of the asteroid which probably killed most of the dinosaurs.

Yeah... so thank the universe that copper has always nearly as many electrons as protons. Otherwise, it would kill all life on the surface of earth.

So the "strength" that we are talking about is related to the coupling constant (which is some inherent property of an interaction I presume) and not to charge/mass ratio right?

Quote by mfb 					 				 				Yeah... so thank the universe that copper has always nearly as many electrons as protons. Otherwise, it would kill all life on the surface of earth.
Did you by any chance draw inspiration from this thread? ;D

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Quote by mishrashubham 					 				 				So the "strength" that we are talking about is related to the coupling constant (which is some inherent property of an interaction I presume) and not to charge/mass ratio right?
The charge to mass ratio is buried in the coupling constants.

$$\alpha_G=\frac{2 \pi G m_e^2}{hc}$$
$$\alpha = \frac{2 \pi k_e e^2}{h c}$$

Quote by DaleSpam 					 				 				The charge to mass ratio is buried in the coupling constants.  $$\alpha_G=\frac{2 \pi G m_e^2}{hc}$$ $$\alpha = \frac{2 \pi k_e e^2}{h c}$$
Oh ok I guess I need to come back to this issue after I've understood the mathematic behind coupling constants. Thanks for all the replies

As far as I understand, the strong nuclear force is so effective because it only acts within a small radius, i.e. comparable to the radius of the average atomic nucleus. Due to the small acting area it becomes much more concentrated and thus has a significantly greater effect, hence nuclear binding events and difficulties that arise during nuclear fission. Our current understanding as to why gravity is significantly weaker is because it acts over a theoretically unbound area. It has been proposed that this is due to the force's ability to act across and through different spacial dimensions and thus cause interactions between objects that could be on opposite 'sides' of a Universe. If there exists a graviton, it is proposed by quantum mechanics that every single fermion in existence exchanges gravitons with every single other fermion in existence. This means, theoretically, that if you move a pen in front of you one metre to the right, you will be altering the forces that are acting on Betelgeuse (obviously the effects are too insignificant to even comprehend, but quantum theory says they're there). The only implication to this seemingly limitless exchange of energy is that it becomes extremely weak in the process. So weak in fact that we can overcome the gravitation of an object of mass 5.97x10^24 kilograms by simply lifting our arm. In conclusion, it's all about concentration. The sum of the magnitude of the fundamental forces of nature may actually be quite similar, but the area over which they're spread out has unquestionable effects on their force per area and hence their 'strength'. This is why gravity is so weak and the strong nuclear force is so much stronger.

Recognitions:      Gold Member  I don't think that's correct Jakus. The weak force acts on an even smaller distance than the strong force, yet it is extremely weak. Also, the strong force doesn't really 'fall off' with distance. Indeed, the strength of the force doesn't drop off at all! What happens is that when you try to pull the quarks apart inside an atom, at a certain point the energy required to pull them further apart is more than the energy required to simply create two new quarks. So two new quarks are created, which bind to the previous two quarks, and you have new particles. Each composite particle has no net color charge, so the strong force isn't felt further away than a few nucleons, much like the EM force isn't felt far away from a neutral atom, but still allows them to bond when they get very close.

I apologise, but I'm unable to determine a contradiction between my post and yours. It seems that we are on separate tangents to each other ^.^ I respect your position and experience on this forum and out of the two of us you're most likely to be correct, but could you emphasise the point in my post that you disagree with?

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Well, let's see:
- the strength of the nuclear force is not related to its range
- the nuclear force does not have a short range

Quote by JakusLarkus 					 				 				Our current understanding as to why gravity is significantly weaker is because it acts over a theoretically unbound area.
This is just wrong.

It has been proposed that this is due to the force's ability to act across and through different spacial dimensions and thus cause interactions between objects that could be on opposite 'sides' of a Universe.
Who proposed the highlighted part (in relation to extra dimensions) where?

If there exists a graviton, it is proposed by quantum mechanics that every single fermion in existence exchanges gravitons with every single other fermion in existence.
That is not restricted to fermions, it applies to bosons as well. You don't need quantum theory for that, however, the classical theories of gravity predict the same.

The only implication to this seemingly limitless exchange of energy is that it becomes extremely weak in the process.
How is that an implication?

So weak in fact that we can overcome the gravitation of an object of mass 5.97x10^24 kilograms by simply lifting our arm.
To do this, you use the electromagnetic force, which has an infinite range as well, and is stronger by more than 30 orders of magnitude.

The sum of the magnitude of the fundamental forces of nature may actually be quite similar
It is not.

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Quote by JakusLarkus 					 				 				I apologise, but I'm unable to determine a contradiction between my post and yours. It seems that we are on separate tangents to each other ^.^ I respect your position and experience on this forum and out of the two of us you're most likely to be correct, but could you emphasise the point in my post that you disagree with?

Your assertion that the strength of the force depends on how far away interaction can take place. Aka how 'concentrated' it is. The weak force, being much more concentrated than the strong force should be much stronger, yet it is not. Then you'd have to compare gravitation with the EM force. Both have the same range and fall off at the same rate, but the EM force is much stronger than gravitation.

Or to put my last post in shorter words, the strong force acts within such a small range BECAUSE it is so strong, not the other way around. If it were weaker, then the energy required to separate quarks would be less and the range would be larger since the screening effect would happen further away.

Message understood, sorry about that. I'm fairly new to this website so is there any way to remove my post?

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Jakus:

I don't want to pile on here, but the following statement is so apparently inaccurate that somebody needs to explain why it is so,

Our current understanding as to why gravity is significantly weaker is because it acts over a theoretically unbound area. It has been proposed that this is due to the force's ability to act across and through different spacial dimensions and thus cause interactions between objects that could be on opposite 'sides' of a Universe.
Newtonian Gravity force F = GM1m2/r2

Coulomb electromagnetic force F = kq1q2/r2

So the electrostatic force and the gravitational force BOTH act over the entire universe. They both weaken as the square of the distance [r] of separation. Neither is 'bounded' [limited] in any way. They become asymptotically weaker a great distances...larger 'r'.

We know the electrostatic force is much stronger because a bit of static electricity can pick up a paper clip...despite the gravitational force opposing that from the entire earth.

On the other hand, when you say gravity acts in 'different spacial dimensions', perhaps that is something you read about string theory. Some propose gravity is weaker in our observed spacetime because because it diffuses into the additional compactified [unobservable] dimensions of such theories. So maybe that's you meant by 'unbounded' area....
so at a minimum the language in the first sentence conflicts with that in the second for virtually all readers here.

don't give up....this is a good place to learn....and most of us take our lumps from time to time....

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Quote by JakusLarkus 					 				 				Message understood, sorry about that. I'm fairly new to this website so is there any way to remove my post?
Not after a day or so. And don't worry, there's no need to remove it anyways. It would just confuse people who read this thread after it was deleted. Who knows, someone may have the same idea you did and having this conversation shown could help them.

Ok, thanks guys. And yeah I'm not sure why I said 'Unbound', I wanted to say 'large area'. It seems that I entered this website thinking I could have a go at answering a couple of questions and instead learnt a few things myself, so I appreciate your support. I am however, slightly insulted at some of mfb's responses.

Recognitions:      Homework  Help     Science  Advisor  That was not my intention, sorry. English is not my native language, and I do not like to write 100 words if I can express the same content with 10 or 1. Can you explain which parts appear slightly insulting to you?

The 'This is just wrong' remark was a bit of a kick in the nuts, but that's ok, I understand =) It's not often you get to converse with decent, respectable people on the Internet but PhysicsForums seems to be a hub for the helpful and considerate. Anyway, I'm straying away from the thread topic and the rules ask us not to so I'll depart. Thanks again, everyone.

Recognitions:      Gold Member  JakusLarkus  hey don't take that personally because throughout the quest for knowledge we all amke and have made mistakes and if someone says that you are wrong (theoretically or empirically) then it is just that your state of knowledge about the matter might need some help not you as a human being , so it is always good to not "fall in love" or take basic physical descriptions of natural laws or phenomenon very personally because later you will find out that either you were wrong at some point about them or maybe science will have something better at the time to offer as an explanation.  We all have made mistakes and history of science also the history of the world as a whole is full with them , but then again they are here to help us become better so every "kick in the balls" makes you stronger in this case.

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Hi Jakus....you said ..

The 'This is just wrong' remark was a bit of a kick....
perhaps some posters will even be mean intentionally.....you have two choices here....if you just want to show off and somebody criticizes you, well that's just too bad.....on the other hand if you want to learn, then accept corrections when you believe them accurate....

Did you survive, learn something, and move on.....bravo, that's the key to life!!!

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