Why should the Bullet Cluster focus light?

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Earnest Guest said:
From your comments, you also don't understand the difference between strong lensing and weak lensing. I suggest you go back and review the materials before trying to act as an 'advisor' on this subject again. There is simply no foundation for being able to simplify a weak lensing problem as a point source. You must perform a statistical analysis of all the stars in a region before you can draw a contour map. There's some good material on the Wiki pages about it.
https://en.wikipedia.org/wiki/Weak_gravitational_lensing
Earnest Guest said:
I'm afraid you just haven't been following the conversation. In addition, I don't think you have a grasp of the concepts here. The Bullet Cluster doesn't have enough mass to create any strong lensing effects. The only effects are 'weak' lensing effects which can only be seen in a statistical blip in the shape of the stars inside the projected radius of the cluster.

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The weak lensing effect extends out beyond the projected radius of the cluster which is causing the lensing.

And it is typically measured from the distortion of the shapes of galaxies (not individual stars) which are out beyond the cluster causing the lensing.
 
phinds said:
Just as an aside, you have STILL never acknowledged your mistake in thinking that convexity/concavity has something to do with gravitational lensing and that there is a similarity with optical lensing. Do you still believe that it is true?
Take two black holes. Place them relatively close together. Now look at a distant SNe Ia that lies directly between the two black holes. Will this supernova appear to be magnified or de-magnified?
 
This may be a case of "don't feed the argument". We've had plenty of calm peaceful friendly discussion of weak lensing (e.g. as used to map concentration of DM mass) here at PF since, as I recall, 2005. We don't need vituperation about who said what and who was wrong etc etc. It doesn't add any useful understanding. AFAICS. That is just my private opinion---I'm not a mentor (they do the moderating).
I'd give everybody a pass and lock the thread, if it were up to me.