In astrophysics, the gravastar (a portmanteau of "gravitational vacuum star") is an object hypothesized in a 2006 paper by Pawel O. Mazur and Emil Mottola as an alternative to the black hole theory.
[2][3] In the original formulation by Mazur and Mottola,[4] a gravastar is composed of three regions, differentiated by the relationship between pressure p and energy density ρ[jargon].
[citation needed] Astronomers search the sky for X-rays emitted by infalling matter to detect black holes.
It is also possible, if the thin shell is transparent to radiation, that gravastars may be distinguished from ordinary black holes by different gravitational lensing properties, as null geodesics[jargon] may pass through.
[citation needed] LIGO's observations of gravitational waves from colliding objects have been found either to not be consistent with the gravastar concept,[8][9][10] or to be indistinguishable from ordinary black holes.
[11][12] By taking quantum physics into account, the gravastar hypothesis attempts to resolve contradictions caused by conventional black hole theories.