I've suggested (& published in 21 journal papers) a new theory called quantised inertia (or MiHsC) that assumes that inertia is caused by horizons damping quantum fields. It predicts galaxy rotation & lab thrusts without any dark stuff or adjustment. My University webpage is here, I've written a book called Physics from the Edge and I'm on twitter as @memcculloch. Most of my content is at patreon now: here

Sunday 17 August 2014

Shawyer's EmDrive

I remember an article in New Scientist a few years ago that discussed something called the EmDrive. This article was criticised at the time by some theoretical physicists, but they couldn't explain the actual anomaly found by Roger Shawyer, an aerospace engineer. He used an asymmetric radio frequency resonant cavity (cone shaped) and pumped a few hundred Watts of microwaves in (just like an asymmetric microwave oven). The cavity then accelerated slightly in the direction of its narrow end, in blatant violation of the conservation of momentum. Shawyer claims this result is predicted by special relativity, while most theorists say a violation of momentum conservation just can't be, but the anomaly itself now seems more solid because it has been reproduced by the Chinese (Juan et al., 2012) and recently by NASA (Brady et al., 2014). The experiment hasn't been done in a vacuum yet, but the abrupt termination of the anomaly when the power is switched off, has been taken as a preliminary demonstration that it is not due to movements of air, but this needs further testing.

This is exactly the sort of naughty violation of momentum conservation that one would expect from MiHsC. It is possible in MiHsC because what is conserved is not mass-energy but Energy-Mass-Information (EMI) and so you can extract energy in a new way, from apparently nothing, by inserting an information horizon into the zero point field. In papers in 2008 and 2013 (see below) I proposed that one could use the recently discovered metamaterials (regular arrays of metal shapes) to make artificial information horizons and thereby interfere with the Unruh radiation that is assumed to cause inertia in MiHsC, and by this means cause anomalous motion. Therefore, the asymmetric metal structure used by Shawyer is of interest to me. Nevertheless the proof is in predicting the right numbers and I haven't worked out how to model Unruh waves in a cavity, in my usual simplified manner yet. Anyway, thanks to the engineer Roger Shawyer, the Chinese and NASA for providing an interesting anomaly to think about.

It is common for engineers to accept the reality of phenomena that are not yet understood, and it is common for physicists to disbelieve the reality of phenomena that seem to contradict contemporary physics - H. Bauer.


Brady, D., et al., 2014. Anomalous thrust production from an RF test device measured on a low-thrust torsion pendulum. Conference proceedings. Abstract

Juan W., 2012. Net thrust measurement of propellantless microwave thrusters. Pdf

Shawyer, R., 2014. SPR Ltd. Website

Shawyer, R., 2008. Microwave propulsion - progress in the emdrive programme. Pdf

McCulloch, 2008. J. Brit. Interplanet. Soc., 61, 373. Can the flyby anomalies be explained by a modification of inertia?

McCulloch, 2013. Inertia from an asymmetric Casimir effect. Europhys. Lett., 101, 59001. Preprint

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