This morning I asked google for a summary of the criticisms of quantised inertia (QI) from mainstream physics and I received this useful list. I can rebut them all, some do require a lot of explanation, some are just plain wrong and one is actually backwards! The criticisms are in bold with my response below:
QI violates the conservation of momentum.
The way to get something moving without expelling propellant in QI is to damp the Unruh waves seen by the object on one side. This is analogous to a ship in a wavy sea. Image that suddenly, you put a wall to the side of it and damp the waves on that side. The ship now feels more wave impact from the seaward side and gets pushed towards the wall. If the crew could not see the waves they’d think there was some magic afoot and Newton’s third law was being violated, but if they could see the waves they would conclude that on a microscopic level Newton’s third law is satisfied. It is the same with quantised inertia. Damping the Unruh waves on one side of the object you want to move, shifts the centre of mass of the Unruh field to the other side compensating for the movement of the object the other way. This comes through very well in my later emdrive papers (e.g. 2017).
QI violates relativity by giving photons mass inside the emdrive
Photons inside cavities can give that cavity mass while not technically having mass themselves (which is a different and difficult debate). This was shown in a paper by Einstein (1906) and later updated by Jennison (1979).
Abandoning the Equivalence Principle
The equivalence principles was Einstein’s assumption that the gravitational and inertial masses are exactly the same. In quantised inertia the inertial mass is modified slightly, but the point is that the change is independent of mass which means that this change will not be seen in the torsion balance tests used to test the equivalence principle. These tests are just subtle variations of Galileo dropping two balls of different masses off the tower of Pizza – was he trying to hit his critics, who were slimeballs? – they both hit the ground together and so would they in QI, just both slightly faster.
Unruh Radiation is too Weak
It is true that Unruh radiation is weak, but as I show in my 2013 paper on the asymmetric Casimir effect, it is acting at the level of tiny Planck masses and so the effect is the right size to reproduce inertia.
The Maths is Wrong
Renda (2019) usefully pointed out some shortcoming of my previous derivations of QI in which I failed to consider the whole Unruh spectrum, and only looked at the peak, so I responded by deriving the same formula in a foolproof way from the uncertainty principle (see my 2024 book) and the erasure of information by horizons (see my 2020 paper and 2024 book).
Toy Models
It is true that my models tend to be simple, but in my opinion that is an advantage. A simple model is easy to understand, nothing can be hidden and nature tends towards simplicity (Occam). I think the mainstream models are far too complex and they can hide behind that complexity.
Changing Universe Problem
Apparently Stacy McGaugh has said, but not to me, he was an early supporter, that if the QI minimum acceleration was true then galaxy rotation speeds would vary in time and they don’t. Well, this was the point of my 2017 paper on galaxy rotation. QI indeed predicts that early galaxies should spin faster for the same mass and there is now evidence that that does happen, as I show in that 2017 paper and you can also see it in the recent discovery of the Little Red Dots by the James Webb Telescope.
Falsification by Wide Binaries.
This is the weirdest criticism them all. It is backwards. I published a paper with J. Lucio in MNRAS (2019) to show that wide binaries are the best proof of quantised inertia. These twin stars show the same orbital anomalies as galaxies, but dark matter cannot be used to correct them. QI predicts the odd wide binary orbits exactly.
Publication Issue
This criticism was that QI papers are hard to publish, but that has not been my general experience. I’ve published 28 of them, 1 or 2 per year. Perhaps one third of the ones I’ve submitted have been accepted and all my papers (almost all) have eventually found a home. QI is new but I always show that it predicts the data simply which reviewers find it hard to complain about.
References
Einstein, A., 1906. Ann. Phys., 20, 627–633.
Jennison, R.C., 1979. What is an electron. Wireless World, June 1979. 42-46.
McCulloch, M.E., 2013. Inertia from an asymmetric Casimir effect. EPL, 101, 59001.
McCulloch, M.E., 2017. Galaxy rotations from quantised inertia and visible matter only. Astro. Sp. Sci., 362,149.
McCulloch, M.E., 2017. Testing quantised inertia on emdrives with dielectrics. EPL, 118, 34003.
McCulloch, M.E. & J. Lucio, 2019. Testing Newton/GR, MoND & quantised inertia on wide binaries. Astrophys. Sp. Sci., 364, 121.
Renda, M., 2019. A sceptical analysis of quantised inertia., MNRAS, 489, 1, 881-885.
McCulloch, M.E., 2020. Quantised inertia and galaxy rotation from information theory. Advances in Astrophysics, 5, 4, 91-94.
McCulloch, M.E., 2024. Quantised Accelerations. Polaris Books.
