Black Hole Size

[johnfosteruk]

Working. On a Sunday. Grrr

[barkis]

And the Wife's been giving me a haircut.  So how will that impinge on the no-hair theorem ?  Good thing is, she found no blackheads to squeeze out this time, as I have spent little time in my workshop of late.                                                                  Right chaps, back to the  Black Hole topic proper. 

[johnfosteruk]

20 minutes ago, barkis said:

                                                          Right chaps, back to the  Black Hole topic proper. 

I'd love to get back to the topic proper but I'm still wrapping my head around @SilverAstro's paper trail... in between work stuff. 

[barkis]

35 minutes ago, johnfosteruk said:

I'd love to get back to the topic proper but I'm still wrapping my head around @SilverAstro's paper trail... in between work stuff. 

I got bogged down in the list of Paradoxes. I'm bowing out of this,
my head hurts, and it's not from the wife giving me a  haircut .

[SilverAstro]

1 hour ago, johnfosteruk said:

wrapping my head around @SilverAstro's paper trail...

Ah, another pilgrim, when you've done please come back (!) and explain it in simple terms that I can understand.

it's all a bit boggling.

[ollypenrice]

I rather feel that I should be listened to on the subject of black holes because I am a living (just about) manifestation of the No Hair Theorem.

Olly

 

[Paul M]

This talk of rotating black holes reminds me of a book I enjoyed as a boy; The Iron Sun, by Adrian Berry https://www.amazon.com/Iron-Sun-Crossing-Universe-Through/dp/0446897965

Just about the only thing I remember from it was how a rotating black hole would have two event horizons. The space between the two ( at the equator) might be a navigable gateway to another place in this universe or perhaps even another universe.

That might also be the book that had an idiots guide to Maxwell's Equations in the appendix. 

 

[SilverAstro]

2 hours ago, ollypenrice said:

I rather feel that I should be listened to on the subject of black holes because I am a living (just about) manifestation of the No Hair Theorem.

Join the queue ! although I have quite a lot it is all roots out the chin and little top-growth no one needed to know this !

Back to topic -  I think it was that 'title' that sustained me thro' the paper chase, it suggested that even cosmologists have a quantum of humour

 

[LukeSkywatcher]

On 19/03/2017 at 11:59, johnfosteruk said:

From hubblesite.org:

 

The size of the event horizon (called the Schwarzschild radius, after the German physicist who discovered it while fighting in the first World War) is proportional to the mass of the black hole. Astronomers have found black holes with event horizons ranging from 6 miles to the size of our solar system. But in principle, black holes can exist with even smaller or larger horizons. By comparison, the Schwarzschild radius of the Earth is about the size of a marble. This is how much you would have to compress the Earth to turn it into a black hole. A black hole doesn't have to be very massive, but it does need to be very compact!

I dont pay much attention to BH's, but i found this absolutely fascinating.