Critical Phenomena
Near the threshold of black hole formation, the spacetime geometry and matter fields exhibit critical behavior, discovered numerically by Choptuik in 1993
The threshold of black hole formation can be found by fine-tuning an appropriate one-parameter (p) family of initial data. The threshold solution is denoted by p=p*. For p>p* a black hole will form during evolution of the data, while for p<p* no black hole forms.