Recent content by particlemania

the last step - \frac{{\partial}x'^a}{{\partial}x^c}\frac{{\partial}x^c}{{\partial}x'^b}=\frac{{\partial}x'^a}{{\partial}x'^b}=\delta^a_b seems quite incorrect to me. Since 'c' is a dummy variable here, over which the expression is summed, hence shouldn't it be ...

Well what is the apparent force applied on two bodies of mass m1 and m2 due to Cosmological Constant? First of all, what is the meaning of a constantly accelerating expansion of universe? Is the second time derivative of volume constant or that of the diametric size of universe? Well in a...

Gravity towards Center of Mass?? Conceptual question: Does gravity always act from the center of mass, regardless of shape of source of field, for finite mass distributions?

Well I'm no expert at GR, but as far as my knowledge of Modifications of Sr goes, it works completely fine at macroscopic distances and small energy levels. The error comes from the fact that by Principle of Relativity, not only is c constant in all inertial frames, but all physical constants...

Thanx a lot!

Well as I am still on Special Relativity, I am still not very comfortable with tensors being used as potentials. Also I couldn't guess what that phi \phi was for... Although I can imagine how, in strong fields, the velocity and direction of motion will have great influence on potential energy.

Why do photons, gluons, and all massless particles move at c? and will this fail if the Equivalence principle is disproved?

So does that mean that PE loses its meaning in General Relativity. If that is so, there must be some equivalent, something that tells us about the energy contained in a body for keeping it static with respect to a g-field...

@Fredrik : So for massless particles, if my third term becomes 0 then momentum should be p = \frac{h}{\lambda} isn't it?

Well the point that E has lorentz factor too was quite obvious if p had and m didnt.

That means among all variables there (except E) only p has a lorentz factor. Thanks a lot!

I'm still on special relativity, and haven't yet reached general relativity, but had a question in mind... does the Newtonian description of Gravitational Potential Energy U= -G \frac{M m}{R} fail for very strong gravitational fields? or it only fails where curvature of space becomes...

so m is rest mass, while p is momentum with lorentz factor?

"E2 - p2c2 = m2c4" - Meaning of symbols What do the symbols mean in the equation- E2 - p2c2 = m2c4 I know this is so basic, but I am really confused about what all are rest parameters here, and what all involve Lorentz factor...

but i can't really use computer during exams!