Posted:

**Mar 02, 2011 9:32 pm**They're the things that allow you to do parallel transport of a vector. I'll let John Baez describe parallel transport to you because he's good at making things visual:

http://math.ucr.edu/home/baez/gr/parallel.transport.html

ETA by the way a picture of the scenario Baez is describing is in the wikipedia article

A geodesic is a curve that parallel transports it's own tangent vector. It's thus the "straightest" curve possible between two points on a manifold (like spacetime) that may be curved. It's the curve that a freely falling body will follow.

CdesignProponentsist wrote:

And what is the difference between the acceleration and gravitational force?

only a factor of m.