How Does Special Relativity Explain Particle Attraction?

[analyst5]

Hi folks,
I was thinking about this question for some time and I need some clarification. What is the take by relativity on electromagnetic forces and attraction between molecules, and other particles on a smaller scale? How do they compose objects on a macro level? I know that action at distance is impossible in relativity, so I believe that this facr certainly has some impact in the answer.

I'm looking forward to the answers.

 

[mfb]

I know that action at distance is impossible in relativity

You can express everything with fields and local field equations, without instantaneous actions at a distance.

Quantum field theory includes special relativity, and it leads to the classical forces between charged particles in the limit of low energies (non-relativistic particles).

 

[HallsofIvy]

But the general problem of connecting the various forces is one of the important problems in modern physics. We really don't know the full answer to that question.

 

[mfb]

I don't see how connecting the different forces (mainly gravity with the other forces) is related to the question. All current (fundamental) descriptions of forces are based on special relativity.

 

[analyst5]

I don't see how connecting the different forces (mainly gravity with the other forces) is related to the question. All current (fundamental) descriptions of forces are based on special relativity.

Can you describe any of those in short terms?

 

[mfb]

Wikipedia can do it better:
General relativity ("GR", gravity)
Quantum field theory ("QFT") -> quantum chromodynamics (strong interaction) and electroweak interaction (with Quantum electrodynamics for electromagnetism alone)

Both GR and QFT need special relativity - with nonrelativistic mechanics, they could not work in their current form.