Naked Science Forum

On the Lighter Side => New Theories => Topic started by: mrMan on 21/02/2011 05:26:31

Title: I dont understand why ever one thinks black holes circular ?
Post by: mrMan on 21/02/2011 05:26:31
you could still spin around and be a different shape maybe you could slam the top of that circle it would a half circle with wave on it and a shore line
Title: I dont understand why ever one thinks black holes circular ?
Post by: imatfaal on 21/02/2011 11:47:07
The sphere is the shape that minimizes gravitational potential - ie any other shape is more energetic and can/will decay to the sphere (things tend towards the lowest energy state).  Some models of black holes spin - so I guess that an oblate distortion would occur - but the maths of being sure on this is way beyond me.  I am not sure I can follow the second half of your question.
Title: I dont understand why ever one thinks black holes circular ?
Post by: Bored chemist on 21/02/2011 19:37:36
Nobody has ever seen a black hole. It's widely hypothesised that they are point like. Does a point have a shape?
I think what the OP means is something like this.

but the "surface" of a black hole isn't real, there's nothing there to "splash"
Title: I dont understand why ever one thinks black holes circular ?
Post by: CliffordK on 21/02/2011 21:51:16
That must be a space bubble, as I've never been able to make a bubble of water that stable.

I was thinking of the Solar System Heliosphere, based on the sun's movement through space.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fthumb%2F4%2F4f%2FVoyager_1_entering_heliosheath_region.jpg%2F220px-Voyager_1_entering_heliosheath_region.jpg&hash=45a648c7bdfc8fa0a5c9f68ba96f1f9e)

However, apparently that model is now being revised.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fthumb%2F5%2F54%2FPIA12375.jpg%2F220px-PIA12375.jpg&hash=14d9caeeb6e031e5077fdb116f40eb71)

See Wikipedia.
http://en.wikipedia.org/wiki/Heliosphere

Anyway, a sphere is a minimum energy.  In fact, planets and moons over a certain size all coalesce into spheres. 

Of course, our Earth isn't a perfect sphere either...  it has a bulge in the middle.

The black hole is likely spinning, and not all forces around the black hole will be uniform.