Here are some schematics to show how MiHsC explains inertia, for the first time, in a mechanistic way, and also the observed cosmic acceleration. This explanation is equivalent to my previous explanations using Unruh waves fitting into the cosmic horizon, but uses Rindler and cosmic horizons only, no waves, for simplicity.
Imagine a spaceship in deep space (the black central object, below). It sees a spherical cosmic horizon, where objects are diverging away from it at the speed of light (the dot-dashed line). This line is an information horizon, so the people on the spaceship can know nothing about what lies behind it. This horizon produces Unruh radiation (orange arrows) that hit the ship from all directions. The spaceship is firing its engines (red flames) and accelerates to the right (black arrow), so information from a certain distance to the left can never catch up with the spacecraft, so a Rindler information horizon appears behind it to the left, and MiHsC says that the Rindler horizon damps the Unruh radiation from the left (the orange arrows disappear) so more radiation hits from the right and a leftwards force appears that opposes the rightwards acceleration. This predicts inertial mass (McCulloch, 2013) which has never before been explained, only assumed.
Now imagine the spaceship starts to run out of fuel, so that its acceleration rightwards decreases (smaller red jet, smaller black arrow, see below). Now the Rindler horizon moves further away (the distance to it is c^2/a, where c is the speed of light and a is the acceleration). Now a bit more Unruh radiation can arrive from the left so the net Unruh radiation imbalance and the inertial force is weaker, to mirror the lower acceleration:
Now the engine dies completely, and you would expect there to be no acceleration at all. The Rindler horizon is just about to retreat behind the cosmic horizon, but before it does the ship now feels Unruh radiation pressure almost equally from all directions, so its inertial mass starts to collapse..
As its inertia collapses the spacecraft becomes suddenly very sensitive to any external force, including from the gravitating black dot in the bottom right of the picture, so it is now accelerated towards that (the lower inertia makes the gravitational attraction seem stronger than expected, as an aside: this fixes the galaxy rotation problem without the need for dark matter) and a new Rindler horizon appears near the top of the picture to produce an Unruh field that opposes the acceleration
It turns out that in order for the Rindler horizon to be disallowed from retreating behind the cosmic horizon, there is a minimum acceleration allowed in MiHsC which is 2c^2/Theta where Theta is the Hubble diameter (the width of the observable cosmos). This acceleration is similar in size to the recently observed cosmic acceleration, and explains it without the need for dark energy.
McCulloch, M.E., 2013. Inertia from an asymmetric Casimir effect, EPL, 101, 59001. http://arxiv.org/abs/1302.2775