Quote by NCStarGazer
Awesome, I see it with better understanding. I know Maxwell's equations and I understand the Lorenz transformation. I was trying to figure out where the attraction comes from in Relativity. We really don't know at present and that is cool, gives a good study in one's spare time.
Do you know where to get more information on the pressure you mentioned in connection with Relativity? I have some math I have been doing with this concept and would love to dig deeper.
Thanks!

Have you studied the book "A first course in GR" by Schutz? In chapter 4, he discusses the perfect fluids in SR which is catchy if you are interested in learning beyond pressure, something like the components of the energystressmomentum tensor (e.g. pressure, density and nongravitational force fields) can be well pinned down via his book at first glance if you have a good knowledge of calculus/SR.
The strong weak and electromagnetic forces have been unfiied (combined) mathematically and they seem to have a common origin...but gravity remains outside that combination.....so we really don't know what the forces are, nor mass, nor time, nor space either...

Well, I don't think the strong force has been combined with the other two. There is just an electroweak theory which covers electromagnetism and weak force together!
AB