Geodesic Curvature (Curvature of a curve)

In summary, Can anyone point me to good reference that fully develops the geometry of geodesic curvature? Most of the ones I have manage to derive it, then show it's the normal to the curve, then never mention it again. I want to know how it relates to the metric, first second or third. Thanks. The speaker is seeking a reference for a thorough explanation of geodesic curvature and its relationship to the metric. They have looked at several sources but have not found one that fully develops the concept. They also mention their interest in understanding how geodesic curvature relates to the metric and ask for any recommendations from the group.
  • #1
Reality_Patrol
109
1
Can anyone point me to good reference that fully develops the geometry of geodesic curvature? Most of the ones I have manage to derive it, then show it's the normal to the curve, then never mention it again.

I want to know how it relates to the metric, first second or third.

Thanks.
 
Physics news on Phys.org
  • #2
Reality_Patrol said:
Can anyone point me to good reference that fully develops the geometry of geodesic curvature? Most of the ones I have manage to derive it, then show it's the normal to the curve, then never mention it again.

I want to know how it relates to the metric, first second or third.

Thanks.

I'm not sure what you mean by "first second or third." But, as I seem to be endlessly saying, I recommend Do Carmo's Geometry of Curves of Surfaces for a very rich discussion of curvature (geodesic curvature in particular) in 3-space and what it means. Much of the topic regarding curves in a general Riemannian manifold is similar in flavor.

As far as I know, the geodesic curvature isn't the normal of the tangent of the curvature, rather it is more or less the length of the derivative of the tangent vector, and it tells you whether the curve is instanteneously geodesic at a particular point or not.
 
  • #3
I think he means first and second fundamental forms. Is there a third fundamental form?
 
  • #4
it occurs to me that you might find what you're looking for in the 2nd volume of Spivak's A Comprehensive Introduction of Differential Geometry.

In order to better answer your question, it would help to know what your objective is in studying geodesic curvature (ie what do you want to do with it?) and what resources you've looked up so far.
 
  • #5
Doodle Bob said:
As far as I know, the geodesic curvature isn't the normal of the tangent of the curvature, rather it is more or less the length of the derivative of the tangent vector, and it tells you whether the curve is instanteneously geodesic at a particular point or not.

That's exactly the kind of thing I'm looking for, but I'd like to see it developed in a more explicit form of course. Thanks for the references, I'm studying GR. But I've found that the geometry is clearer to me if developed in 3-space first then generalized to n-space. Thanks guys.
 
  • #7
robphy said:
Possibly useful:

On the differential geometry of curves in Minkowski space
http://arxiv.org/abs/gr-qc/0601002

What publication does this paper come from? It's excellent, and I want to find more like it.
 
  • #8
Reality_Patrol said:
What publication does this paper come from? It's excellent, and I want to find more like it.

It is indeed very cool. Thanks for pointing it out.
 
  • #9
Reality_Patrol said:
What publication does this paper come from? It's excellent, and I want to find more like it.

http://arxiv.org hosts e-prints, which may or may not end up in other publications [like journals or books]. To find others like it, I'd start by searching for other articles by the authors on arxiv.org and on the web using http://scholar.google.com/ . Then, I'd search for similar topics and titles.
 
Last edited by a moderator:

What is geodesic curvature?

Geodesic curvature is a measure of the rate at which a curve deviates from a straight line in a curved space. In other words, it measures the amount of "bend" in a curve as it follows the shortest path between two points on a curved surface.

How is geodesic curvature calculated?

Geodesic curvature is calculated using the formula k_g = (T x T')/|T|^3, where T is the unit tangent vector to the curve and T' is the derivative of T with respect to arc length. This formula can also be written as k_g = |dθ/ds|, where θ is the angle between the tangent vector and the surface normal vector.

What is the significance of geodesic curvature?

Geodesic curvature is an important concept in differential geometry and has many applications in physics and engineering. It is used in the study of curved surfaces, such as the Earth's surface, and in the calculation of trajectories in curved spaces.

How does geodesic curvature relate to other types of curvature?

Geodesic curvature is one type of curvature that is specific to curves on curved surfaces. It is related to other types of curvature, such as normal curvature and Gaussian curvature, which measure the amount of "bend" in a surface at a given point.

Can geodesic curvature be negative?

Yes, geodesic curvature can be negative. This occurs when the curve is bending in the opposite direction of the surface's normal vector. In other words, the curve is bending away from the surface rather than following its natural "bend." Negative geodesic curvature can be seen in the shape of a saddle or in a curve on a negatively curved surface.

Similar threads

  • Differential Geometry
Replies
6
Views
2K
Replies
10
Views
2K
  • Differential Geometry
Replies
1
Views
1K
  • Special and General Relativity
Replies
8
Views
472
Replies
21
Views
1K
  • Differential Geometry
Replies
3
Views
2K
  • Special and General Relativity
Replies
27
Views
4K
  • Special and General Relativity
Replies
30
Views
618
  • Differential Geometry
Replies
6
Views
2K
  • Special and General Relativity
Replies
6
Views
1K
Back
Top