Is Cosmic Censorship a requirement?

[imatfaal]

There is a requirement for singularities to have a horizon. 'Naked' singularities are not allowed.

However the BB singularity ( if there was one ) could be different as there is no 'outside' to shield it from.

 

That being said, Sorcerer, if we look back into the past expecting to see the event horizon of the BB singularity, we would be 'outside' the universe. This is an impossibility as the BB singularity and its attendant horizon is what expanded to become the universe.

 

Cosmic censorship is a hypothesis with a lot to be said for it - but at present it is untested and untestable

[MigL]

Not so fast imatfaal...

This may be off-topic, and if so, I apologise.

The cosmic censorship hypothesis may be unproven, but everything has an event horizon.

If we define the horizon as the radius where the escape velocity is equal to/greater than c , then, if we get close enough to any standard model massive particle, we eventually encounter an event horizon, as standard model particles are 'dimensionless'.

This is not noticed as the event horizon, in such cases, has a radius nearly equivalent to zero, i.e. it coincides with the point-like particle.

 

When the event horizon is 'equivalent' to the particle size, light can escape from it and we can 'see' it.

If this were the case for a black hole ( extreme mass ) singularity, i.e. if it was 'naked', we would be able to 'see' an edge or end ( or beginning ) of space-time. In effect a 'cusp' ( don't know if that term applies ) in the space-time manifold where it is not continuously differentiable.

[imatfaal]

Split from other thread. It may be a while before I can respond in more depth - but as I have told people off for being off topic in that very thread I thought it better for this branch to be pruned

 

 

In this paper we study the dynamics of the trapped region using a frame independent semi-tetrad covariant formalism for general locally rotationally symmetric (LRS) class II spacetimes. We covariantly prove some important geometrical results for the apparent horizon, and state the necessary and sufficient conditions for a singularity to be locally naked. These conditions bring out, for the first time in a quantitative and transparent manner, the importance of the Weyl curvature in deforming and delaying the trapped region during continual gravitational collapse, making the central singularity locally visible.

 

Aymen I M Hamid et al 2014 Class. Quantum Grav. 31

 

Warning/Acknolwedgement - I do not really know what the above quote means, but I read more pop-like articles about the the possibility the ccc is not necessarily true and now I am trying to find meat to go on those bones.

 

[OT] What is Classical Quantum Gravity? [/OT]

[ajb]

I guess the best we can say at this point is that under some reasonable physical assumptions general relativity does not allow naked singularities. In this mathematical sense it is 'proved'. But then we have the question of the assumptions needed and how we exactly formulate the presence of a singularity and so on.

[Mordred]

I guess the best we can say at this point is that under some reasonable physical assumptions general relativity does not allow naked singularities. In this mathematical sense it is 'proved'. But then we have the question of the assumptions needed and how we exactly formulate the presence of a singularity and so on.

I will concur, I've read numerous proofs on the naked singularity issue, enough to know possible, but not highly agreed upon. Though not my specific interest. I leave that in the hands of the specialists in that arena.