Quote:
Originally Posted by Robh
Mark,
Does anyone really know what happens inside the event horizon?
I can't comment about the internal physics but this is my opinion of the picture outside it.
Consider objects with different mass traveling at the same velocity towards a common centre in a plane, each object initially at equal distance from this centre. Now move the plane near a black hole (non-rotating) so that a radial line from the centre of the black hole is normal to this circle at its centre. The path of the objects will lie on a surface which was the plane but is now symmetrically distorted towards the black hole relative to the normal. This is the picture of a sink hole given for the black hole or equivalently a representation of the curvature of space around the black hole. To a distant observer the path of each object is essentially similar and two dimensional and distances covered will diminish with time as the objects approach the event horizon. At the event horizon, the objects appear to stop.
The visual representation of a sink hole around a black hole is not entirely accurate and is for impression only. There are an infinite number of such planes that will form their own sink holes relative to the black hole. A picture of this cannot be drawn in three dimensions.
However, for a single object, the path is essentially two dimensional with a relativistic time component.
Regards, Rob.
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Rob - very well expressed.
Alex actually captured my conundrum - though I wouldn't use the language expressed. However - I'd like to leverage of Alex's reply - as it was more succinct. Basic problem is how can space-time be curved in on itself and information still be exchanged between the singularity and a mass outside of the event horizon.
That implies that there is a path from within the event horizon to out side - as outside knows what mass lies within the event horizon.
My line of enquiry doesn't seek to challenge existing theory - merely to inch towards a better understanding of what current theory says. But I have a suspicion that General Theory of Relativity is such that one probably needs to have a mathematical appreciation as qualitative explanations are just going to be an oversimplification to the point of being useless.
I appreciate Alex's comment - as it is so succinct.
Rob, your comment regarding knowing what happens at the other side of the event horizon is also thought provoking. From what I read - nothing changes other than all paths lead to the singularity and hence no particle can move from the inside to the out side. If the black hole were sufficiently massive then the gravitational gradient may not be that great across a short distance that crosses the event horizon and an observer crossing the event horizon wouldn't really experience any change to his environment when he crossed it - physics is still predictable. But an observer outside would not see this - but can predict it. Again, from the perspective of an outside observer timings of events as they approached the event horizon would slow down. But what we see is increasingly red-shifted to the point where we can't see them any more. Now - at some point (post event horizon) closer to the singularity our laws of physics may break down for the observer that is falling in - and at the singularity - I would expect this as I'm sure there are many equations that have the radius - or distance from centre - as a denominator and when you get zero we have stuff that can't be computed. I'm of the understanding that it is the division by zero is what mathematicians call a singularity.
I can buy a lot of this but its the conundrum of how information is shared (re gravity) between inside and outside of the event horizon that I can't visualise.
Mark C.