White Holes are Christmas Magic

In classical General Relativity, White Holes (WH) refer to the time reverse Schwarzschild (SW) Black Hole (BH) solution of a point mass \(M\) and gravitational radius \(r_S=2GM\). The SW metric is static so that a time reverse WH solution simply corresponds to a violation of causality. The WH solution does not make any physical sense here. For a more physical model, such as the Lemaitre-Tolman-Bondi (LTB) metric with finite mass inside \(r_S\), we show that both the expanding and collapsing solutions correspond to a BH and not to a WH.