Talk:Cauchy horizon

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logical gap

There seems to be a logical gap at "As this happens infinitely many times while approaching the horizon..." The article doesn't explain why this would happen infinitely many times.--76.167.77.165 (talk) 13:41, 24 May 2009 (UTC)[reply]

The article no longer says this. Answer is, I guess, periodic boundary conditions. The Penrose diagram tiles -- just repeats over and over. 67.198.37.17 (talk) 18:55, 18 April 2019 (UTC)[reply]

Strong Cosmic Censorship over-turned

Apparently two GR-mathematicians have disproved the strong cosmic censorship conjecture, replacing it with (paraphrasing, possibly unfaithfully) "the manifold on the other side of the Cauchy horizon isn't smooth enough" to address Einstein's equations for GR beyond the horizon. Secondary source: https://www.quantamagazine.org/mathematicians-disprove-conjecture-made-to-save-black-holes-20180517/?fbclid=IwAR3EOTiCd2u9dp-JzX3N_XWsSfpScE7zDVcN9wG3zwnUV1sVaeTII0NDDL4 This presumably warrants an update to this page (by someone who knows more about Cauchy horizons) – Eddy. 84.212.155.77 (talk) 14:52, 4 January 2020 (UTC)[reply]

Yep. What I saw was something about 5-D black holes, and diff-eq's no longer being integrable after the Cauchy horizon. I guess this can be rephrased as being "no longer smooth". The paper I saw actually constructed an explicit, naked (ring) singularity in 5D, so not only "disproved it" but constructed an explicit example. Of course, we live in a 4D world, not 5D. 67.198.37.16 (talk) 05:49, 23 May 2023 (UTC)[reply]

Comprehensibility

I have a reasonable grounding in physics, and could hardly understand a word of this. There's no point in an article that can only be understood by those who already know all about it. Suggest a parallel (and longer) article at say undergraduate level. GrahamRounce (talk) 18:53, 22 February 2024 (UTC)[reply]

Agree. What I did not understand was the word "closed". What does it mean for a geodesic to be closed? Or put another way, how could a timelike geodesic be closed?