# Start a new discussion

## Not signed in

Want to take part in these discussions? Sign in if you have an account, or apply for one below

## Site Tag Cloud

Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

• CommentRowNumber1.
• CommentAuthorzskoda
• CommentTimeJun 22nd 2010
• (edited Jun 22nd 2010)

I am at the Croatian black hole school organized by Jarah Evslin, and I am partially taking care of Croatia related issues (visa, trasnportation advice. communication to the owners of the housing). Lots of interesting things here about star formation, black hole formation, making massive black holes from lighter ones and so on. And some string theory mechanisms related to black hole entropy and similar issues. Most of people are postdocs and students here. Among seniors, Holger Nielsen and Mina Aganagić are present to our benefit.

By the way, started a stub black hole. Please contribute.

• CommentRowNumber2.
• CommentAuthorzskoda
• CommentTimeJun 22nd 2010

OK also an event stub Croatian black hole school. By the way notice the drawings for the posters of the school on the web age of the school linker there.

• CommentRowNumber3.
• CommentAuthorUrs
• CommentTimeJun 22nd 2010

Thanks Zoran! Keep us posted.

I have edited the entry a bit.

Notice by the way that we already have an entry Kerr spacetime but could use an entry Schwarzschild spacetime

• CommentRowNumber4.
• CommentAuthorzskoda
• CommentTimeJun 22nd 2010

Well, I wrote a real time part of 3rd lecture of Mario Pasuiato under new entry observing black holes, diagrams from the lecture missing. Maybe I can improve later from the notes which we got at the school from the speakers, and assembled into a mini book by Jarah Evslin.

• CommentRowNumber5.
• CommentAuthorzskoda
• CommentTimeJun 22nd 2010

Added redirects Kerr black hole, Kerr-Newman black hole to Kerr spacetime.

• CommentRowNumber6.
• CommentAuthorzskoda
• CommentTimeJun 22nd 2010
• (edited Jun 22nd 2010)

So you have there fast and slow and extreme, we were using terminology superextreme for Kerr black holes which I guess you call fast ?

The treatment you have has nothing about the various instabilities. Any comment ? The Penrose diagram has a coordinate extension with infinitely many Rindler space areas both in past and in future, what breaks down under any perturbation.

• CommentRowNumber7.
• CommentAuthorUrs
• CommentTimeJun 22nd 2010

So you have there

Sounds like you are talking to me. Notice that I didn’t write any substantial part of Kerr spacetime. Tim van Beek did!

• CommentRowNumber8.
• CommentAuthorzskoda
• CommentTimeJun 24th 2010

It is not important who wrote the previous stuff but who can comment on the current question :)

The entry Kerr spacetime, as I see now is not suitable as a redirect to Kerr-Newman black hole, as the latter is more special. For example, the zero charge zero momentum, that is Schwarzilchild case does not count as Kerr black hole, the latter really means nonzero stuff.

• CommentRowNumber9.
• CommentAuthorTim_van_Beek
• CommentTimeJun 24th 2010

So you have there fast and slow and extreme, we were using terminology superextreme for Kerr black holes which I guess you call fast ?

Since the Kerr spacetime has two parameters, there are three possibilities when you compare them :-) So if superextreme is “rotating faster than in the extreme case a=M”, then yes, fast = superextreme :-)

The treatment you have has nothing about the various instabilities. Any comment ?

Not from me, all I had in mind was a wrap up of several discussions we had on the nLab. Plus I don’t know much about stability of spacetimes.

• CommentRowNumber10.
• CommentAuthorUrs
• CommentTimeJan 19th 2011
• (edited Jan 19th 2011)

pasted snippet about black hole topology theorems into black hole.

• CommentRowNumber11.
• CommentAuthorUrs
• CommentTimeApr 10th 2019
• (edited Apr 10th 2019)

added pointer to the first resolved image of the direct vicinity of $Sagittarius A^\ast$, announced a few minutes ago: