# Flying near Kerr (ring) singularity

## Main Question or Discussion Point

I know it is very unlikely such thing exists because QM can prevent CTLs

However, what observer would see near such singularity?
As ring is timelike, for an observer it won't be a ring at all, but a point, correct?
That point should be visible (naked) because there are no horizons between an observer and singularity?

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PeterDonis
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As ring is timelike, for an observer it won't be a ring at all, but a point, correct?
No, it would be a ring. "Timelike" just means it follows a timelike worldline, like an ordinary object. And yes, it will be visible if you're inside the inner horizon.

Any point object creates a timelike worldline in block time. Why Kerr Ring should be different? If it is timelike, it should be observed (by an observer close to the ring) as a point. "Ring" just tells us that an observer is inside closed timeline curve...

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WannabeNewton
If it is timelike, it should be observed (by an observer close to the ring) as a point. "Ring" just tells us that an observer is inside closed timeline curve...
The Kerr singularity is a cylinder in space-time. It is a ring in the Boyer-Lindquist spatial coordinates so Peter is correct i.e. only its "spatial topology" is a ring. This has nothing to do with CTCs as the CTCs exist in a neighborhood of the ring singularity, not on it, and has to do with the fact that in this neighborhood the axial Killing field becomes time-like while retaining its closed orbits.

Interesting, thank you
So what we would see - optically, and what we would "see" if we try to compensate pure optical effects?
I understand it is quite difficult to answer this question without a detailed simulation, however, all simulations I've seen cover only non rotating BH

Thank you!!!!!!!
Exactly what I was looking for!

Wow, just downloaded the program, that is a great find, thanks! Having just finished my own Kerr orbit program, it looks like I will be able to drive animations from this using my data files. Fantastic!