The Bullet Cluster is often taken as a proof of dark matter, but dark matter is so flexible that anything could be taken that way. The cluster is shown in the composite picture below (from NASA's Chandra X ray observatory). The pink areas are the visible matter. The bullet, the pink 'cone' to the right, from its symmetry, looks as if it has moved from left to right and has crashed through the pink mass on the left.
Figure 1. The Bullet cluster, visible mass (pink) & inferred dark mass (blue)
By looking at the bending of starlight arriving from behind these masses, astronomers have proposed the presence of their favourite fudge, dark matter, shown by the blue areas. Well, I never did like fudge as a child, and I still don’t, so let’s see if quantised inertia will explain this instead and in a way that does not need fudging.
Quantised inertia predicts that every time the mutual accelerations get very low, and that happens especially along spin axes (see my referenced paper on the flyby anomaly below), then the inertia decreases in a new way and particles, including photons, should bend more under gravity, making it look like there is dark matter when it is actually a QI effect instead. Sure enough, the blue areas are along the spin axis of the cluster (a spin I have deduced quite reasonably from the rotational symmetry of the Bullet, its cone shape.)
Let’s see if the numbers fit. The mass of the Bullet is 2x10^14 Solar masses, and the distance to the centre of the blue area to the right of it, is, roughly 250 kiloparsecs. So the acceleration there is
a = GM/r^2 = 4.7x10^-10 ms^2
By now, if you have been following me for 20 years you may be getting fed up of this number (or values close to it) which crops of everywhere in deep space, but I love to see it. What this means is that the Bullet Cluster, far from proving dark matter, supports QI in two ways. The blue areas are along the axis as predicted by QI, and the acceleration is indeed low enough in the blue areas to make QI effects important.
I hope you have enjoyed this latest Bullet-in, for more like this, but twice a week, please subscribe at my patreon https://www.patreon.com/OneSteptoTauCeti
Reference
McCulloch, M.E., 2008. Modelling the flyby anomalies using a modification of inertia. MNRAS Letters, 389 (1), L57-60 https://academic.oup.com/mnrasl/article/389/1/L57/996711
