Penrose-Carter diagrams
(a) In the Penrose-Carter (PC) diagrams for Minkowski spacetime, plot lines of constant t and constant r (where t,r are Minkowski coordinates).
(b) Consider two metrics, g_(ab) and tilde(g)_(ab)=f(x^(k))^(2)g_(ab), with f(x^(k)) a real function. Show that the light cone structure of their PC diagrams are similar as long as f(x^(k))!=0. Explain the difference that arises when there exists a domain where f(x)=0 by comparing the PC diagrams of Schwarzschild geometry, Minkowski spacetime, and of Schwarzschild spacetime with negative mass (that is, with M<0 in the metric).
(c) Consider a class of metrics g_(ab)=f(x^(k))^(2)eta _(ab), with f(x^(k)) a real function. Obtain the Christoffel symbols for g_(ab) and show that timelike/spacelike geodesics of eta _(ab) are not necessarily timelike/spacelike geodesics of g_(ab).
Penrose-Carter diagrams
a In the Penrose-Carter (PC diagrams for Minkowski spacetime, plot lines of constant t and constant (where t,r are Minkowski coordinates)
(b) Consider two metrics, 9ab and gab = f(x)2gab, with f(x) a real function. Show that the light cone structure of their PC diagrams are similar as long as f( 0. Explain the difference that arises when there exists a domain where f(c)= 0 by comparing the PC diagrams of Schwarzschild geometry, Minkowski spacetime, and of Schwarzschild spacetime with negative mass (that is, with M < 0 in the metric)
(c) Consider a class of metrics gab = f(x2nab,with f(x) a real function. Obtain the Christoffel symbols for gab and show that timelike/spacelike geodesics of nat are not necessarily timelike/spacelike geodesics of 9ab.