Learn more physics! I have been reading about gravitational
lensing. All the models I have seen discuss light going around
the outside of some gravitational source, like a black hole or
something. Would it act more like a traditional lens if passing
through the middle a source that was more donut shaped, instead
of around a ball type shape? If so, could somethig like this be
done experementally? - Michael French First of all gravitational
lenses are not like the reading glasses you buy at WalMart.
Ordinary optical lenses focus a point source into a point image.
Gravitational lenses focus a point source into a circular line
image. Sometimes you see only a small arc of the circle
depending on the relative positions of the source and lens. As
to whether or not a doughnut shaped lens would work, I haven't
worked it out in detail but I suspect the answer is no. Could
one perform an experiment? In principle yes, but there are not
too many doughnut shaped galaxies out there. I presume you have
read the Wiki article: