Black-Hole Singularities: A New Critical Phenomenon

The singularity inside a spherical charged black hole, coupled to a spherical, massless scalar field is studied numerically. The profile of the characteristic scalar field was taken to be a power of advanced time with an exponent α>0. A critical exponent α_crit exists. For exponents below the critical one (α<α_crit) the singularity is a union of spacelike and null sectors, as is also the case for data with compact support. For exponents greater than the critical one (α>α_crit) an all-encompassing, spacelike singularity evolves, which completely blocks the “tunnel” inside the black hole, preventing the use of the black hole as a portal for hyperspace travel.