Cosmic Nudity !!! Is it really censored?- January 15, 2016, 11:00 a.m. SPS Boardroom


Dr. Rituparno Goswami

Senior Lecturer & Gravitational Physicist

Astrophysics & Cosmology Research Unit

University of Kwazulu Natal Durban, SA


In nature, Black Holes have a troublesome sibling called "Naked

Singularity". When a massive star collapses under its own gravity, the

entire mass of the star concentrates at the centre, making the central

density infinite. This is a singularity in the spacetime where density and

curvature diverge. It was conjectured by famous physicist Sir Roger

Penrose, that such singularities must always be hidden within Black holes,

from which nothing can escape. Therefore it is never possible to "see"

these singularities and thus they are "censored" from all observers in the

universe. As yet, no proof for this Censorship Conjecture is available and

rigorous calculations show that it is not always true. The final fate of a

collapsing massive star is either a black hole or a visible naked

singularity.  These naked space-time singularities may even provide a

laboratory in the cosmos where one could test the unification possibilities

of basic forces of nature.


Solutions of spherically symmetric spacetimes in modified gravity



The common picture of the Universe is that it is made up of spherical or

approximately spherical stellar objects immersed in vacuum. These spacetime

objects produce gravitational fields that are approximately spherically

symmetric and can be represented as spherically symmetric solutions to the

gravitational field equations. We investigate the problem of spherically

symmetric spacetimes in the context of modified gravity and in particular

we focus on f(R) theories of gravity.