Trying to get a basic understanding of the 4 key forces?

[paulo84]

Hi again,

I find this topic particularly fascinating. Can anyone point me to a good article/or provide a summary which explains how the 4 fundamental forces work? If possible not wikipedia, I find wikipedia very jargon-y.

I did a search and found some rubbish I posted a couple of years back and not much else. Thanks in advance.

Or, if someone could start with some key concepts and allow me to then ask questions?? Thanks for your time.

 

[paulo84]

It may be helpful if I give an idea of what I know so far:

I have knowledge and understanding of the EM spectrum explained visually. I also have some understanding of the importance of differences in waves.

I understand gravity in terms of acceleration due to gravity.

I don't know very much about strong interaction and weak interaction, but I was not bad at Chemistry in school (which included some quantum chemistry).

 

[Arman777]

Hi again,

I find this topic particularly fascinating. Can anyone point me to a good article/or provide a summary which explains how the 4 fundamental forces work? If possible not wikipedia, I find wikipedia very jargon-y.

I did a search and found some rubbish I posted a couple of years back and not much else. Thanks in advance.

Or, if someone could start with some key concepts and allow me to then ask questions?? Thanks for your time.

http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/funfor.html

You should try to search more deep.I hope this helps.

 

[paulo84]

http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/funfor.html

You should try to search more deep.I hope this helps.

How do they test that the range isn't infinite?

 

[paulo84]

'It now appears that the common form of the gravity and electromagnetic forces arises from the fact that each of them involves an exchange particle of zero mass, not because of an inherent symmetry which would make them easy to unify.'

The problem is there are so many weird shapes...

 

[paulo84]

Even if you're operating on the basis of symmetry, with multiple dimensions there are so many weird shapes?

 

[lekh2003]

'It now appears that the common form of the gravity and electromagnetic forces arises from the fact that each of them involves an exchange particle of zero mass, not because of an inherent symmetry which would make them easy to unify.'

The problem is there are so many weird shapes...

I think symmetry in this situation means every particle having an anti-particle.

 

[paulo84]

I think symmetry in this situation means every particle having an anti-particle.

'This is often called the "universal law of gravitation" and G the universal gravitation constant. It is an example of an inverse square law force. The force is always attractive and acts along the line joining the centers of mass of the two masses. The forces on the two masses are equal in size but opposite in direction, obeying Newton's third law. Viewed as an exchange force, the massless exchange particle is called the graviton. From Einstein's treatment in general relativity, gravity is associated with a curvature of space-time and changes in mass configuration can produce gravitational waves.

The gravity force has the same form as Coulomb's law for the forces between electric charges, i.e., it is an inverse square law force which depends upon the product of the two interacting sources. This led Einstein to start with the electromagnetic force and gravity as the first attempt to demonstrate the unification of the fundamental forces. It turns out that this was the wrong place to start, and that gravity will be the last of the forces to unify with the other three forces. Electroweak unification (unification of the electromagnetic and weak forces) was demonstrated in 1983, a result which could not be anticipated in the time of Einstein's search. It now appears that the common form of the gravity and electromagnetic forces arises from the fact that each of them involves an exchange particle of zero mass, not because of an inherent symmetry which would make them easy to unify.'

(bolded part mine). can you please explain that in some detail?

 

[lekh2003]

(bolded part mine). can you please explain that in some detail?

I'd love to give my opinion and explanation, but I feel another member with more expertise would be able to answer that question.

 

[Arman777]

Graviton is a hypotetical particle.

Bold part means that gravity is the weakest force respect to the electromagnetic force (or respect to other forces).

For example, Consider two particle each 1kg and they are 1m apart, The force that they will exert is about $10^{-11}N$. Meanwhile two particles with 1 Coulomb charge in each and If we set the distance as 1m we have approximately $10^{10}N$.

So the electromagnetic force $10^{21}N$ times stronger than gravity in this case.

http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/unigrav.html

We need high (really really high) amount of energy to combine the gravity with other forces. Its hard to construct such a mathematical structure that explains this pheomena.

 

[paulo84]

Graviton is a hypotetical particle.

Bold part means that gravity is the weakest force respect to the electromagnetic force (or respect to other forces).

For example, Consider two particle each 1kg and they are 1m apart, The force that they will exert is about $10^{-11}N$. Meanwhile two particles with 1 Coulomb charge in each and If we set the distance as 1m we have approximately $10^{10}N$.

So the electromagnetic force $10^{21}N$ times stronger than gravity in this case.

http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/unigrav.html

We need high (really really high) amount of energy to combine the gravity with other forces. Its hard to construct such a mathematical structure that explains this pheomena.

I get what you're saying about the bold part. But is the reason gravity is so hard to combine with EM because of the really really high energies, or because gravity is behaving in a funny way which means it doesn't correspond exactly? 'It now appears that the common form of the gravity and electromagnetic forces arises from the fact that each of them involves an exchange particle of zero mass, not because of an inherent symmetry which would make them easy to unify.'

 

[Drakkith]

But is the reason gravity is so hard to combine with EM because of the really really high energies, or because gravity is behaving in a funny way which means it doesn't correspond exactly?

I think it boils down to the fact that gravity isn't quantizable, unlike the other fundamental forces which are. We run into the problem that trying to quantize gravity results in infinities that can't be gotten rid of using renormalization. In other words, the techniques used in other quantum theories to get rid of these infinities don't work for gravity.

I find this topic particularly fascinating. Can anyone point me to a good article/or provide a summary which explains how the 4 fundamental forces work? If possible not wikipedia, I find wikipedia very jargon-y.

That jargon is usually necessary to begin to understand the topic. You can almost certainly find simpler articles elsewhere online, but they will probably be so over-simplified that much of what they are saying is wrong or near-useless.

 

[paulo84]

I think it boils down to the fact that gravity isn't quantizable, unlike the other fundamental forces which are. We run into the problem that trying to quantize gravity results in infinities that can't be gotten rid of using renormalization. In other words, the techniques used in other quantum theories to get rid of these infinities don't work for gravity.
That jargon is usually necessary to begin to understand the topic. You can almost certainly find simpler articles elsewhere online, but they will probably be so over-simplified that much of what they are saying is wrong or near-useless.

Is there any value to looking at the force gravity in terms of very complex shapes that might account for the problematic infinities? Or am I thinking too visually?

 

[Drakkith]

Is there any value to looking at the force gravity in terms of very complex shapes that might account for the problematic infinities?

I seriously doubt it.

 

[paulo84]

I seriously doubt it.

Can you shed some insight on how physicists are trying to deal with problematic infinities?

 

[Drakkith]

Can you shed some insight on how physicists are trying to deal with problematic infinities?

Unfortunately no. I know very little about renormalization and related topics.