# Understanding the 3 coordinate systems for a Schwarzschild geometry

1. Jan 20, 2010

### JeffOCA

Hello,

There are 3 main coordinate systems for a Schwarzschild geometry : Lemaitre-Rylov (LR), Eddington-Finkelstein (EF), Kruskal-Szekeres (KS).

Thanks to my readings, I know thaht KS coordinates are better than EF coordinates and that EF coordinates are better than LR coordinates. But, I don't really understand why !

I have also read that LR coordinates use timelike geodesics (how can you see that ?) and that EF and KS coordinates use null (lightlike) geodesics (once again, how can you understand that ?)

Jeff
France

2. Jan 22, 2010

### JeffOCA

Up !

3. Jan 22, 2010

### Staff: Mentor

I would not describe one coordinate system as "better" than another in general. Which coordinate system is best depends on the application.

Here is an arxiv paper on a generalized form of Schwarzschild coordinates which reduces in special cases to the above. I found it useful: http://arxiv.org/abs/gr-qc/0311038