@DaleSpam Sigh I just don't get it then…
I am not a priori against what you said but I don't get what the coordinates system (t,x^0,x^1,x^2,x^3) is supposed to describe. It cannot be coordinates on the tangent space because there are two different values for the metric at two locations \vec...
That's true I had not noticed that metric compatibility has that meaning! Thank you very much for pointing that out!
Ok let's see if I understand things better now.
Let's say I have a small cannon in my room. I set up a coordinates system and now contemplate the space-time distance tau a ball...
First of all thank you everyone for answering!
Yes you are right, in fact I meant a fixed reference frame on some point on the geodesic.
I understand the tangent space as the best linear approximation to the manifold endowed with a constant metric (hence tangent space is flat) but I am not...
I am having trouble connecting some of the differential geometry in gr to what is actually measurable in the real world.
As far as i understand we can measure physical quantities in terms of coordinates x^\mu on the tangent space of a 4-dim Pseudo-Riemannian manifold M. So let's say we are...