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

Thursday 24 May 2018

Emdrive Trial by Media

You may have noticed that some of the mainstream scientific media are attempting to debunk the emdrive based on Tajmar's new result, but the data suggests that Tajmar does not yet even have a working emdrive and is looking at some sort of Lorentz force.

To demonstrate this, here is a plot showing Tajmar's newly measured thrust in comparison to the other ones. The thrust predicted by quantised inertia is shown on the x axis and the thrust observed is shown on the y axis. The diamonds show the comparison between the predictions and the data. Most of the diamonds line up along the diagonal line, meaning that QI does a good job of predicting the results (as does the Shawyer equation that also uses power times Q). One point to note is you can predict the thrust from the characteristics of the cavity (eg: Q, length, widths) not the cables. Tajmar's new thrust is way below the line (see the label: Tajmar2018). The thrust expected by QI for his setup was 0.19mN and his observed thrust was 0.004mN. This is almost fifty times smaller! If you have a car that is going 50 times slower than expected, then you can probably conclude that the engine is off. So it seems that Tajmar is not testing an emdrive yet, but is looking at some other, much smaller, effect.

This is further supported by comments from Phil Wilson who has pointed out that the cavity Tajmar is using does not have a resonance at 1.865GHz (the frequency he is inputting) and his results look very much like something else is resonating.

Also, what has been forgotten is that NASA were well aware of the potential problem of a Lorentz force, and showed their thrust was not from that. In their 2017 paper (see below, page 838, top right column) they said "The [cavity] was tested in forward, reverse and null orientations, but dc power cabling, routing & orientation was the same for all three configurations". What this means is that the NASA emdrive's thrust direction followed the cavity orientation and not the cable orientation. Therefore for a real working emdrive, it is the cavity and not the cables that make the thrust.

This is not a criticism of Tajmar, who I have the greatest respect for, but for the media response to his preliminary tests:


White et al., 2017. Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum. Journal of Propulsion and Power, Vol. 33, No. 4 (2017), pp. 830-841 https://arc.aiaa.org/doi/10.2514/1.B36120

If you wish to support my work a little, you can do so here:


Zephir said...

The EMdrive is not so simple device as it looks at the first sight, as it generates thrust by polarization of microwaves by repeated reflection under Brewster's angle. There is considerable know-how in Shawyer's original design: everything - the shape, the placement of waveguides, etc. - matters here. Creating a replica doesn't warrant that this replica will fly, until you don't know about principle of its function.

But who cares about some dumb physicists after all? They never had working plans of nuclear bomb neither from good reason. Chinese have it, NASA too.

Mike Warot said...

I share your view... it seems like anything on the edge of useful gets squashed if it threatens the status quo.

I bought your book, I'm about 1/2 way through.

Sorry if this is a repeat... it seemed to eat my first attempt at a comment.

PeterVermont said...

Scott Manley has a nice 8 minute video overview of the experiment although he does not address Mike's point that Lorentz Force was tested for and eliminated in NASA testing...

Simon Derricutt said...

Mike - today the dead chicken cartoon has disappeared. Please restore it, unless you think that poking fun is unprofessional. I thought it was good....

Replications of such "outrageous" devices do tend to run into problems like these where the person trying to replicate is really trying instead to prove it doesn't work, and hasn't understood why the thing worked in the first place. Momentum is not actually exactly conserved where the field is changing, and the greater the rate of change of the field the more the error in conservation of momentum. That's using schoolboy physics (reaction between a current and a magnetic field), without going into QI or anything complex. It's thus not really a question of whether CoM is broken, but of how large the effect is. With unchanging fields, CoM is however precise, and that's what we normally work with.

joesixpack said...



Quote by the lead researcher:

""[Dark matter] is the scaffolding on which galaxies are built … Not seeing it means that something else happened.""

Maybe this will be what gets the academy to skewer CDM.

Czeko said...

Shadoks@work pumping harder.


Zephir said...

Modified gravity declared dead yet again"We find that MOND modified inertia models, frequently used to fit rotation curve data, are disfavoured at more than 5σ independent of model details."

Mike McCulloch said...

Zephir: They have not tested QI: the formula they used is from MoND and is different.

Jimmy Johnson said...

Lest you let the state of scientific investigation get you down just reflect on the quote:

“The two most common elements in the universe are hydrogen and stupidity.” (Harlan Ellison)

It helps keep things in perspective. Eventually reality trumps stupidity and science progreses. As for hydrogen it remains.

Jimmy Johnson

joesixpack said...

"We find that MOND modified inertia models, frequently used to fit rotation curve data, are disfavoured at more than 5σ independent of model details."

What about dark matter though?!

It is not even necessary for galaxy formation.

Hold up. I think we've all missed a wry joke here; the paper supports MOND and rejects DM, but because DM is still the dominant paradigm, researchers tend to be mealy-mouthed to let the facts sink in for those who prefer research results to be set in stone like the Encyclopedia Britannica article they read when they were 13...

Five sigma is pretty significant. Zephir is actually posting information in support of modified gravity and inertia theories.

"At more than 1 in 3.5 million simulations, the MOND model is rejected..."

Come on guys, let's think about what those p-values mean. Let's read the full abstract, at least!

*We study geometries of galactic rotation curves from Dark Matter (DM) and Modified Newtonian Dynamics (MOND) models in (gbar,gtot)-space (g2-space) where gtot is the total centripetal acceleration of matter in the galaxies and gbar is that due to the baryonic (visible) matter assuming Newtonian gravity. The g2-space geometries of the models and data from the SPARC database are classified and compared in a rescaled g^2-space that reduces systematic uncertainties on galaxy distance, inclination angle and variations in mass to light ratios. We find that MOND modified inertia models, frequently used to fit rotation curve data, are disfavoured at more than 5σ independent of model details. The Bekenstein-Milgrom formulation of MOND modified gravity compares better with data in the analytic approximation we use. However, a quantitative comparison with data is beyond the scope of the paper due to this approximation. NFW DM profiles only agree with a minority of galactic rotation curves. Improved measurements of rotation curves, in particular at radii below the maximum of the total and the baryonic accelerations of the curves are very important in discriminating models aiming to explain the missing mass problem on galactic scales.*

MOND works every 3,499,999 out of 3,500,000 times whereas DM works at best, 1,749,999 out of 3,500,00 times!

joesixpack said...

First attempt to comment was eaten by spaminator:

I would re-read the article that Zephir linked to. I think he was being humourous. The results, being rejected at five sigma, shows that the chance of the results being false is one in 3.5 million.

I expect QI to have an even smaller p-value, perhaps only being rejected at seven sigma or more.