Recent content by weio

I think our finite minds are not couped well to understand such things, specially when it comes understanding how bizarre nature is. Questions that I'm used to think are "What is all this universe? what is it doing here? Is it really here?". And there you come to deep thoughts you can't get out...

Thanks a bunch! I will look that up. wieo

HI How does a magnetic field build in a natural magnet like iron from a quantum mechanical point of view? I know it has to do with electrons spin and their orbital momentum, but how exactly does it work in a magnet? thanks

Thanks! I understand the derivation now. I found a simple one which fully explains it. for the curious, here is the link :- http://www.anasoft.co.uk/physics/gr/reimann/reimann.html weio

Hey So far this is how I understand it, though I know I could be very wrong. If you have two geodesics parallel to each other, with tangents V and V' , in which the coordinate x^\alpha point along both geodesics. There is some connecting vector w^\alpha between them. Let the affine...

Hey, when calculating the Riemann curvature tensor, you need to calculate the commutator of some vector field V , ie like this :- [\bigtriangledown_a, \bigtriangledown_b] = \bigtriangledown_a\bigtriangledown_b - \bigtriangledown_b\bigtriangledown_a = V;_a_b - V;_b_a But...

Hi everybody If we assume that all we observe and see and touch (ie. the universe) was 'real', not illusion, what would there be if this "reality" didn't exist? The first thing that pop up to my mind is 'nothingness', but do we really know what nothingness means? is it just a dark place...

Hi I guess i could have written it as X_p(f) = a^i ( \frac {\partial f} { \partial F^i} )(p) , but i missed the f , my bad. Anyways, I understand now, but I think I need more time to get used to the notion of vector fields and tangent vectors. Thanks for the clarification. weio

Hi Fredrik, HallsofIvy, and all First of all thanks for the explanation Fredrik and HallsofIvy, but just to make sure i understand this, i will try to give an example. Let X_p be a tangent vector in an open neighborhood U of a point p \in R^n and let f be a C^\infty function...

Hi there Can somebody please explain shortly the difference between a tangent vector and a vector field? I'm still new to differential geometry. I read couple of sources that had mixed claims on which of them actually act on a given function f. so I'm kind of confused. Much appreciated.

Hi there I've been trying to find out how spacetime curvature actually produce gravity, but all i can find is articles using math, which is far too advanced for me to understand. Can anyone give me a theoretical explanation to how the gravity arise from the spacetime curvature according to...