Comments on Je me promène dans les trous noirs de Kerr

Ruxor (2018-09-10T16:51:26Z)

@jonas: The fact is, there is only so much information that can fit into 280 characters, so it's hard to always put in all the fine print and disclaimers. 😉

jonas (2018-09-10T12:39:54Z)

Ah, I see. You already corrected the bragging the next day, in <URL: https://twitter.com/gro_tsen/status/1021778372890976257 > (Twitter entry on 2018-07-24T15:25:22+00:00). Sorry.

jonas (2018-09-10T12:28:51Z)

If I understand this entry correctly, you claim here that you first made videos of black holes in 2011-03. Then in https://twitter.com/gro_tsen/status/1021493818846334977 (your Twitter entry on 2018-07-23T20:34:39+00:00), you claim that you were the first to compute black hole videos. But I don't think that's correct. In my 2016 comment here I linked to a site with earlier videos. Some of the links are broken (they probably already were as I posted), but <URL: http://jila.colorado.edu/~ajsh/insidebh/intro.html > works, and from there you can get to <URL: http://jila.colorado.edu/~ajsh/bh/schwhist.html >, which claims that Andrew Hamilton has published videos of black holes in 1998. Sure, they're only videos of Schwarzschild black holes, not of Kerr black holes, and they are of technically lower quality by those 10 years, but they should still count.

And I think his concise illustrated explanation of unstable Schwarzschild white holes and of wormholes stabilized by negative energy exotic matter <URL: http://jila.colorado.edu/~ajsh/bh/schww.html > is still a useful reference to complement your white hole <URL: http://www.madore.org/~david/weblog/d.2017-11-06.2476.white-holes.html > page, because it tells what happens in the simpler non-rotating case.

In any case, yes, your black hole articles and videos are a great resource, and you can brag about them, just be careful with phrasing your bragging precisely.

jonas (2018-03-18T17:54:16Z)

Scott Aaronson <URL: https://www.scottaaronson.com/blog/?p=3659 > points to a well-written obituary for Stephen Hawking by Roger Penrose <URL: https://www.theguardian.com/science/2018/mar/14/stephen-hawking-obituary >, which talks a bit for a general audience about Hawking's research on black holes. This seems like the most appropriate blog entry where I can mention this.

jonas (2016-09-26T10:00:37Z)

Two other websites about black holes that I'd like to link from here for reference.

In <URL: http://math.ucr.edu/home/baez/diary/september_2016.html#september_2 >, John Baez writes about how light can orbit around Kerr black holes on unstable orbits. He tells that unlike with Schwarzschild black holes, for Kerr black holes there's no single photon sphere, in the sense that for almost any given points of the trajectory of an orbiting photon, there are only finitely many orbits passing through. I hope either he will continue that series and write more about black holes, or you will continue <URL: http://www.madore.org/~david/weblog/d.2011-04-08.1863.intro-relativite.html#d.2011-04-08.1863 >.

Baez links to Andrew Hamilton's page about black holes <URL: http://jila.colorado.edu/~ajsh/insidebh/intro.html > and <URL: http://casa.colorado.edu/~ajsh/schw.shtml >. These have computed videos of falling into Schwarzshild and Reissner-Nordström black holes, as well as some short popular explanations about the theory of black holes. Elsewhere Andrew Hamilton's page has an old list of links to other websites about general relativity and black holes <URL: http://casa.colorado.edu/~ajsh/relativity.html >, although it appears that most of the links are broken.

hijodelachingada (2011-03-09T03:15:51Z)

A priori les experts du domaine adoptent le point de vue d'un observateur distant. L'envoie de sondes n'est pas pris en charge par les assurances.

Ruxor (2011-03-07T22:08:23Z)

xavier → Je ne sais pas exactement. Je suis quasiment certain que personne n'a jamais fait de vidéo équivalente à celle que je viens de calculer (i.e., de traversée d'un trou de ver *pour un trou noir de Kerr* ; il y en a une pour un trou noir de Reissner-Nordström qui est montrée par certains planetariums), mais je ne sais pas au juste ce qui limite.

Fred le marin → Plutôt galactiques. Sur une image fixe ça ne peut pas se voir, mais dans ma vidéo l'échelle de temps est telle que le trou noir a une masse de 1000000 masses solaires. Dans un trou noir stellaire un observateur humain serait déchiqueté bien avant d'arriver à l'horizon, alors qu'un trou noir galactique est bien plus tolérant, si j'ose dire.

Fred le marin (2011-03-07T20:29:49Z)

Sont-ce des trous noirs stellaires ou galactiques ?
J'ai une "Introduction à la Géométrie Différentielle" de Monsieur Aimé,
et c'est très difficile à lire…
(Ce message est lié à une fluctuation du vide quantique)

xavier (2011-03-07T13:30:42Z)

Est ce que les experts du domaine ont un tel code? En mieux?
Est ce que ca peut leur servir à qqch?


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