Abstract
We examine the causal and geometric horizons of dynamical black holes in Lemaitre-Tolman-Bondi collapsing dust spacetimes. Marginally trapped tubes in these spacetimes may be spacelike, timelike or null and may also be sourced from or disappear into shell-crossing singularities which we resolve with (timelike) shock waves. The event horizon kinks when it intersects a shock wave. We calculate the timelike separation between the crossable boundary (marginally trapped tubes plus connecting shock waves) and event horizon. As measured along the crossable boundary this function can have discontinuities not only in its derivative but also in the function itself. These features are closely related to the geometry of the crossable boundary. Finally, we consider the application of this work for future space explorers seeking to make the closest (nonterminal) approach to a black hole horizon.
3 More- Received 15 August 2014
DOI:https://doi.org/10.1103/PhysRevD.90.084027
© 2014 American Physical Society