It's a gamble, but I think it's important to focus on anomalous experimental results since the new stuff always comes from there so I thought it would be useful to recap what I have been thinking about regarding Shawyer's EmDrive results. You should bear in mind that this is an example of me wildly playing around with ideas and I may decide tomorrow it is wrong. So, just to remind you that the EmDrive is a cone-shaped microwave resonant cavity, like a microwave oven built into a megaphone. When microwaves are resonated in there, it has been shown by Roger Shawyer, also a Chinese group and recently a NASA group that a small anomalous force is produced and the cavity moves towards its narrow end. This apparent violation of the conservation of momentum has not been explained.
To explain it, I've assumed the following: the microwaves bouncing around within the cavity have inertial mass (em radiation does: that's why it can push a Solar sail) and their inertia is determined by MiHsC (quantised inertia). In MiHsC the Unruh waves are allowed only if they fit exactly within the Hubble horizon or within a local Rindler horizon, but what if the cavity wall in this case was acting like a horizon? Well, then the microwaves at the wide end would have more inertia than those at the narrow end since more Unruh waves would fit. This means that as a microwave beam goes from the narrow end to the wide end it gains inertial mass. Now I can try something I've used before (for the Tajmar effect) and say, in order to still conserve momentum (mass*velocity) for the whole system, if mass goes up then velocity must go down, and the only way to achieve that is to have the whole structure move towards the narrow end.
I've done the calculation using MiHsC for Shawyer's EmDrive assuming an input power of 850W, a frequency of 2.45GHz and a Q factor (number of times the waves bounce before dissipating) of 5900 and I predict a force of 12.75mN, close to the 16 mN they saw.
Again, do take this in the spirit of 'playfulness'. There are huge questions: How can I throw out the rule book on photons like a hippy on LSD, and then insist on conserving momentum like an accountant with OCD? It could be a just a coincidence that it works, but it is interesting. Comments welcome!
