[sjastro]

Originally Posted by Jarvamundo

Thanks SJ, I'm starting to piece together the illogical geometric picture a Schwardschild Black Hole Lense creates... This is not what the gravitational lense simulators show.

To me it seems to be violating all geometry i am familiar with in all aspects of empirics... generally the inverse square root law, which is apparent is nearly all nature .... hmm...

I think we are starting to get somewhere atleast with trying to describe Schwartschld characteristics.

What we are saying is that a Schwardschild black hole lense IS NOT the same as a gravitational lense?

The same principles apply. The only difference is that we can observe the bending of light as close as the limb of a star or galaxy(s). For BHs this is the event horizon. Bending of light occurs inside the horizon, unfortunately we cannot observe it.

So the bigger a black hole gets, the sharper the gradient of lensing?

From this:

1) Should we not see these stars disappearing as they pass behind SagA*? As they are 'blocked out' by the sharp event horizon.

This would be the only way to directly confirm a black hole exists?

The BH's mass is confirmed by the Keplerian orbits of nearby stars. If the orbiting stars are in the same plane as the accretion disk of the BH then probably we would not be able define a sharp horizon. If the orbits are not in the same plane the event horizon would "eclipse" the stars relative to our frame of reference.

2) Gaussian curvature of light for a large Schwartzchild black hole is not as applicable, as that of as the gaussian curve of a large gravitational body.

a Schwartzchild Geometrical Curvature picture:
small black hole: ````\__/````
large black hole: ```|_____|```

The Gaussian curvature is dependant on the density of an object rather than its mass.
Hence the curvature around a one solar mass star is nearly flat where as the curvature around a one solar mass BH is extreme. The curvature of a supermassive BH is also extreme as we get closer to the centre. We can't observe the effects however due to the event horizon.

It seems the r in the Schwartzchild solution is not the same as the r in the GR gravitational lense solutions? Although it's used when considering gravitational effects of orbiting stars...

On one hand we use r to determine curvature of spacetime and the orbits of stars
Then on the other we can't use r to determine the curvature that would effect light

It seems Schwartzchild BH's get their own special set of rules.
puzzling

Nothing unusual at all.
The GR equation for the bending the light has the R value equal to the radius of the star, for BHs R is the event horizon radius.

I'm taking a break from this thread.

Regards

Steven