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Author Topic: Black holes warping space time  (Read 1669 times)

Johann Mahne

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Black holes warping space time
« on: 16/07/2011 19:00:36 »
Every galaxy has a super massive black hole at it's center that distorts space time so that nothing can escape from it.
How then is it possible that extra galactic jets can emit from the center of the glaxies perpendicular to the black holes?


 

Offline yor_on

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Black holes warping space time
« Reply #1 on: 17/07/2011 01:16:53 »
The only explanation making sense is that it has to happen outside the event horizon. The Black Holes we know of today all spins, as far as I know at least? And as everything falling into them will get 'frame dragged' there might be places that are 'calmer' than others, if you go by chaos theory, defining where energy might find it easiest to 'escape', or it could be a combination of where the concentration of 'energy' is largest, as well as easiest to escape, or either, or none :) In short, until you've gone there to study it, in situ, the best guess is still a guess :)
==

You might assume that the overall gravity of the galaxy it's situated in might 'steer it' too? But compared to the spin (near light speed for some BH) and massiveness we associate with a Black Hole I don't think it can play any major role myself? And there is one intriguing possibility more, possibly? Time dilation? Could that play a role for us observing the 'energies' spewing out? I haven't really thought that one over, but it might matter (a pun), somehow?

I'm not sure of the last one though? I read somewhere that the frame dragging created by our galaxy is about one million times 'stronger' than Earth's own 'spin'. Still, probably puny, if compared to what a super massive Black Hole produces in its own vicinity?
« Last Edit: 17/07/2011 01:38:58 by yor_on »
 

Offline Soul Surfer

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Black holes warping space time
« Reply #2 on: 17/07/2011 10:01:11 »
The explanation is quite simple but seldom described properly in the text books and applies to all bodies collapsing under gravity and not just black holes.

When a body of gas collapses under the influence of gravity any angular momentum is conserved which means that  any rotation it has speeds up (a bit like water going down a plughole).  Randomly moving matter also tends to form a disc because anything that is not moving around inside the disc will meet up with the disc every so often and get deflected into it  also orbits tend to become circularised to minimise collisions.  Now as the collapse progresses and things speed up and heat up it is natural to think of things flying off the edge of the disk but this is not a rigid body like a roundabout and all the stuff in the outer parts of the disk is in reasonably stable orbits.  However if particles or atoms collide and are deflected away from the disc along the axis of rotation with high energy they can escape the gravitational field.  So on all collapsing bodies you see bipolar flows of material from the poles.

Now black holes whatever their mass are always very small compared with normal matter they also have a great deal of angular momentum and gravitational energy to get rid of before the material can collapse inside the event horizon.  It is in fact extremely difficult to fall into a black hole in spite of all the rubbish talked about them sucking everything in! This is completely untrue.  it would take a long time and release vast quantities of energy for a black hole to consume anything that cannot enter it without being totally disrupted by tidal forces.  The only way this can be released is from the direction of the poles and as orbital velocities near the event horizon are close to the velocity of light and black holes are small, this energy can only be released in the form of very high energy particles and radiation in very tightly collimated beams from the poles.

The effects of frame dragging just increase this need for the radiation to be collimated and from the poles.
« Last Edit: 17/07/2011 10:04:32 by Soul Surfer »
 

Johann Mahne

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Black holes warping space time
« Reply #3 on: 27/07/2011 18:30:47 »
Quote
The only way this can be released is from the direction of the poles and as orbital velocities near the event horizon are close to the velocity of light and black holes are small, this energy can only be released in the form of very high energy particles and radiation in very tightly collimated beams from the poles.
  Thanks for the good explanation.
  What i don't understand is this: Physicists tell us that space time should be heavily warped near the event horizon.These beams radiating from released energy should then have a lensing effect applied on them and should not be radiating away perpindicluar to the plane of the gas?
 

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Black holes warping space time
« Reply #3 on: 27/07/2011 18:30:47 »

 

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