HB: Some of the evidence for "dark matter" ... We know that there is a supermassive black hole consisting of 4.1-4.5 million solar masses at the center of the Milky Way: https://en.wikipedia.org/wiki/Milky_Way
--supermassive BHs in galaxies are only, like, 0.5% of the galaxy mass, or less. So they don't really matter for this, but they do matter in the sense that they seem to stabilize galaxies, and may even be crucial for that.
Our Sun is roughly in the plane of the Milky Way, and "sees" forces from every bit of mass in the Milky Way. I claim that our Sun "sees" larger-than-expected forces from masses approx 180 degrees around the Milky Way due to *gravitational lensing*.
--this effect should be negligibly small. The optical lensing should be of the same order, and it clearly is negligibly small.
I'd love to know if this gravitational lensing effect is very strong compared with the usual centripetal forces on the Sun. In particular, what % addition speed does this lensing effect add to the speed of the Sun around the center of the Milky Way?
--It'll be a tiny amount. Well below 1%. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)