Talk:Penrose diagram/to do

To do
Tasks for expert:
 * explain relation to asymptotic flatness
 * Penrose coordinates: just another kind of coordinate chart (two dimensions are suppressed in the diagram)
 * two metrics, role of "unphysical" metric in tracking energy, etc.
 * derivation and extended discussion of some examples (e.g. Minkowski, Schwarzschild, FRW)
 * illustrations of further examples of Penrose diagrams (Vaidya, Schwarzschild-de Sitter, Reissner-Nördstrom, Kerr)
 * write and link to article on Vaidya thought experiments (see Frolov & Novikov, Black Hole Physics, Kluwer)
 * write and link to article on Bondi radiation formalism
 * write and link to article on black hole interior
 * write and link to article on colliding plane wave (conformal diagrams there are not Penrose diagrams in this sense since points correspond to planar wavefronts, not to nested spheres, but c.f. local isometries with black hole interiors)
 * link to discussion somewhere appropriate of smoothness issues (see arXiv preprints of Dieter Brill)
 * explain why the grid is indeed a conformal transformation of Minkovski space, even though its lines very obviously do not meet at 90 degrees in the diagram

Thereafter, tasks for anyone who wants to help:
 * replace 45 degrees with slope +/-1
 * spell check,
 * improve diction,
 * make citations and links correspond with WikiProject GTR format