Assertion: black hole | /r/DefinedAs | the presence of a singularity
Facets:
value: physically
type: MANNER
Source sentences:
text: Physically, a black hole is defined by the presence of a singularity, i.e., a region of space, bounded by an 'event horizon', within which the mass/energy density becomes infinite, and the normally well-behaved laws of physics no longer apply.