Gravitational Collapse | Dispersion to Infinity vs Black Hole Formation

In gravitational collapse two typical behaviours happen: 1) too much density accumulates, space-time bends too much, leaving behind a black hole from where nothing can escape; 2) without enough density, accumulated matter is expelled in pieces to the universe (a bit like supernovas). The video shows the collapse of a lump of matter in General Relativity (GR), either dense enough to form a black hole or not so much and hence dispersing away to infinity. This was done in the context of the paper in , which studies gravitational collapse as a way to identify interesting aspects of extensions to General Relativity.