Can We See Naked Singularities?

Abstract

We study singularities which can form in a spherically symmetric gravitational collapse of a general matter field obeying weak energy condition. We show that no energy can reach an outside observer from a null naked singularity. That means they will not be a serious threat to the Cosmic Censorship Conjecture (CCC). For the timelike naked singularities, where only the central shell gets singular, the redshift is always finite and they can in principle, carry energy to a faraway observer. Hence for proving or disproving CCC the study of timelike naked singularities will be more important. Our results are very general and are independent of initial data and the form of the matter.

On Time-Dependent Black Holes and Cosmological Models From a Kaluza–klein Mechanism

“…Hence for proving or disproving CCC the study of timelike naked singularities is more important. The results of [45] were very general and independent of the initial data and the form of the matter.…”

“…Deshingkar [45] studied singularities which can form in a spherically symmetric gravitational collapse of a general matter field obeying the weak energy condition. He showed that no energy can reach an outside observer from a null naked singularity.…”

On physical insignificance of null naked singularities

“…This means that, in principle such a singularity can be observed and they can be more problematic. However, as such we expect them to be very rare [37].…”

“…Therefore, it is important to find out whether a naked singularity can affect the physics outside it, i.e., whether a nonsingular observer can distinguish it observationally. With this in mind we studied the spherically symmetric dust collapse model [37] and calculated the redshift and luminosity of light rays coming out of the singularity. Subsequently, we also studied extremely wide class of (any type II matter) spherically symmetric collapse models for the same purpose.…”

“…Different choices for U A will lead to different sets of null geodesics along u = constant, r = constant. In spherically symmetry a shell focusing naked singularity can form only at r = 0 [37] when weak energy condition [5] holds.…”