Many people have asked me for a simple, graphical explanation of how quantised inertia (QI) gets rid of the awful dark matter, so here it is, for them. We start off with a schematic of a galaxy (see below, in yellow). Outer stars have been observed to have a rotational speed (the red arrow) so big that the inertial (centrifugal) forces (white arrow) should be much greater than the gravitational forces from all the matter we can see (the black arrow) and so, if it had any decency, the galaxy ought to fly apart. The problem is that galaxies are showing no decency at all, and do not fly apart. Why? Mainstream astrophysicists add arbitrary dark matter to boost the gravity arrow and achieve balance that way. Quantised inertia shrinks the inertial arrow instead.
To explain quantised inertia I will start with an oceanographic analogy (see below). A ship is parked at a dock. Lots of ocean waves can exist and hit it from the seaward side (the wavy line), but no waves can fit within the gap between the ship and the dock, they don't resonate in that space, so on average the ship is pushed by the waves towards the dock. If the crew of the ship were unaware of the waves they would say "It is a magic force moving us towards the dock!".
There is another sea. One predicted by quantum mechanics. It is a sea of quantum particles, and we have only recently detected it because Hendrik Casimir showed that if you put two plates very close together, like the ship and the dock, the plates will move together. That has now been confirmed (in 1996) so this invisible sea really does exist. Now consider an object accelerating to the right (black circle, white arrow below). It will see the quantum sea, actually an enhanced version of it (Unruh radiation). Relativity now says that in the opposite direction to the acceleration, information will not be able to catch up with the object. So there will be a horizon, like a black hole event horizon (see the black crescent). In quantised inertia this horizon is treated just like the dock wall in the analogy. it damps the waves between the object and itself. As in the analogy the object sees more waves from the right and is pushed back, always against its acceleration. This 'asymmetric Casimir effect' predicts what we always assumed before to be a 'magical' inertial mass, because we couldn't see these quantum waves (which only exist in the object's reference frame).
Information also cannot get to us from beyond the Hubble horizon, since stars there are moving away from us at the speed of light. So this horizon damps the Unruh waves equally all around the object, and so it damps the waves on the right side (there already aren't any on the left) - see the change from the dashed waves to the solid waves, below. This reduces the effect of the aCe process detailed above, and the resistance to acceleration, the inertial mass. This reduction is more serious for the longer Unruh waves that occur for low accelerations,since these 'feel' the cosmic boundary more.
I hope you can appreciate the beauty and simplicity of this theory. It has not yet been tested on the insides of galaxies, I'll need a galaxy model for that, but it does predict a lot of other observations as well such as the cosmic acceleration and the emdrive.
McCulloch, M.E., 2017. Galaxy rotations from quantised inertia and visible matter only. Astrophys. & Space Sci. 362, 149. Link to open access paper
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