I've suggested (& published in 15 journal papers) a new theory called quantised inertia (or MiHsC) that assumes that inertia is caused by relativistic horizons damping quantum fields. It predicts galaxy rotation, cosmic acceleration & the emdrive without any dark stuff or adjustment.
My Plymouth University webpage is here, I've written a book called Physics from the Edge and I'm on twitter as @memcculloch

Wednesday, 21 January 2015

Cultural Inertia


I can't understand how physicists can be content with such poor explanations of nature as dark matter and dark energy. Of course, there are some examples from history where new mass was implied: one student yesterday pointed out to me that Mendeleev's periodic table predicted elements that were then seen later, which is a good example, but in the successful cases like Mendeleev's, or the discovery of Neptune, it was a small bit of extra mass that was needed to fill the gap in a mostly complete structure, interpolation, in the case of dark matter and dark energy physicists are saying they understand 4% of the cosmos and are now extrapolating 96% of it. The reason I think is cultural inertia, which always has been very strong.

One example of cultural inertia was the ancient Greek Aristotle's belief that the Moon was perfectly round. Nearly 2000 years later in 1609 Galileo made a telescope (which had just been invented by Hans Lippershey) and looked at the Moon and saw jagged mountains on it! I can imagine his joy at this discovery, since he was curious and also a bit of a Socratian gadfly but his contemporaries said 'No, the Moon is perfectly round just as the great Aristotle said'. 'How so?', said Galileo. They replied 'It is surrounded by an invisible crystalline layer that is a perfect sphere'. 'Go on, pull the other leg!' said Galileo 'No, really!' they said. I can imagine Galileo's frustration at having his observations countered by a theory that was so ridiculous it was not falsifiable - how can you disprove an invisible layer around the Moon? He could only resort to ridicule and replied 'If you can imagine an invisible layer, then I say there are mountains in the invisible layer 10 times bigger than the ones I can see through my telescope'.

In modern times, old theories die hard just the same: general relativity (GR) was suggested by Einstein in 1915, and even in 1940 he knew it was not the final word (see Feynman, 1985, page 80), since he had a genuine desire to know. It is true that GR has been tested successfully at the high accelerations in our inner Solar system (of order 1 m/s^2), but it has not been tested at the very low accelerations in galaxies (of order 10^-10 m/s^2) that Einstein never imagined, but we have now seen. I wrote in a previous blog that 'no theory has ever survived an extrapolation over ten orders of magnitude' and I think this is vague but probably mostly true, and, surprise surprise, at the edges of galaxies where accelerations are ten orders of magnitude lower, GR fails, and ten times as much mass as can be seen must be added to fix it. Guess what? This mass is invisible. In this case though, there a way to disprove dark matter, and that is that tiny globular clusters behave anomalously just like huge galaxies, but dark matter can't be use to fix them because to be smooth enough to work on galactic scales they can't also work on those small scales. See my blog here.

Alternatively one can modify physics in such a way that it doesn't mess up well-observed high acceleration behaviour, but also fits the new low acceleration data. This is what I have done with MiHsC (see a summary here) which fixes things without needing any invisible stuff, and in fact MiHsC is based on the philosophy that 'if you can't observe it in principle, then it doesn't exist', which was the same kind of Machian approach that led Einstein to relativity.

Cultural inertia is very strong and keeps the majority comfortable, but I think, every hundred years or so, even theoretical physicists are entitled to a bit of excitement.

References

Feynman, R.P., 1985. Surely You're Joking Mr Feynman, 1985. Vintage books.

McCulloch, M.E., 2014. Physics from the Edge, World Scientific. Book

Monday, 12 January 2015

Time from interaction?

Imagine a firefly drifting in an empty universe that can only do three things: remember, detect photons and emit photons. If you follow the principle of Mach that 'if it can't be measured in principle, then it doesn't exist', as I do, then as far as the lonely firefly is concerned there is no time or space since it has no way of measuring them. It could emit a photon of light to try and explore its environment, but the photon will never come back so neither will any information. My intention here is not to make spacetime subjective but to apply the same idea to inanimate objects, and say that if time/space are fundamentally unmeasurable by a system then these abstract quantities don't exist.

Now imagine that suddenly another firefly appears and there are two things in the universe. Now firefly A can emit light and firefly B can respond to A with its own flash. Suddenly A and B have a way to measure time. They can't do this by measuring the time taken for a signal to return because we've already assumed that time without the return of a signal doesn't exist, but if A and B have memories then they can count the number of times they receive a reply and call this time. This begs the questions: does time only exist with interactions? Does it speed up if you have more interactions? I think so, because this suggests a way to resolve the Einstein, Podolsky & Rosen (1935) (EPR) paradox.

In the EPR problem there is a particle with zero spin that splits into two particles, one going left, one right. Quantum mechanics, not to be pinned down, only says that both are spinning both up and down, but if someone measures particle A and finds it spinning up, by conservation of angular momentum we know immediately that particle B must spin down. Since quantum mechanics says there was no information on spin before the particles were measured, and Bell's inequality has allowed people to experimentally confirm this, then this implies that A and B communicate apparently faster than light, in violation of special relativity.

Well, I'd like to suggest these particles are a bit like the fireflys: while they're diverging they can't interact with anything, and so, as above, time cannot exist for them, so at the time (from our external point of view) that they seperated they already knew what would happen at the later measurement time (Being complex beings we have lots of interactions going on so we have a finer measure of time). I've been vaguely thinking this for years (inspired just after my physics degree by reading the Emperor's New Mind by Roger Penrose), but recently I've got stuck in and I've finally worked out a way to justify and quantify this using information theory. I am just about to submit a paper on it..

PS: The brilliant Transaction Interpretation of Quantum Mechanics of Cramer (1986) says something similar, but involves waves sending signals 'through' time rather than, as here, having time itself dissapear.

PPS: The bleak but deep novel by Greg Bear 'The City at the End of Time' involves a sort of collapse of time so different events in history suddenly end up simultaneous.

References

Einstein, A., B. Podolsky, N. Rosen, 1935. Can quantum mechanical description of physical reality be considered complete? Phys. Rev., 41, 777.

Cramer,  J., 1986. Reviews of Modern Physics, 58, 647-688.

Penrose, R., 1989. The Emperor's New Mind.

Friday, 2 January 2015

Bell's Anomaly

As you know by now I'm always in search of anomalies, and probably the deepest anomaly in physics today was first noticed by Einstein, Podolsky and Rosen (1935) (hereafter EPR) who introduced it as a paradox. John Bell (1964) brilliantly quantified it and made it possible for Aspect (1982) to test it and turn it into an anomaly which proves that physics as we have known it, is not deep enough. It also offers possibly the best clue to progress.

Anyway, to put things into context Einstein discovered one half of modern physics: special relativity, which maintains that information travels only at light speed and he also had a hand in creating the other half: quantum mechanics, which says that any quantum system is in an indeterminate state (wavefunction) until it is measured, like Schroedingers 'cat in a box with poison' which is neither alive nor dead until it's seen.

The original EPR paradox implied that these two halves of modern physics are incompatible. It starts by imagining a non-spinning particle splitting into two entangled particles with spin one half. To conserve angular momentum, one must be spin up and the other down. As they zoom away from each other they are in a combined spin up and spin down state, like the dead-alive cat. Imagine you let them get light years apart and then decide to measure the spin of one of them and the particle suddenly decides to be clockwise (collapse of the wavefunction). The conservation of momentum then tells you suddenly that the other particle is spinning anticlockwise, whereas just before it was doing both. Einstein didn't like this because no definite information on spin was encoded in the wavefunction, so how could the second particle know which way to spin, does this information pass between them upon measurement of the first as what he called 'spooky' action at a distance? He thought there must be a sort of invisible DNA inside the particles that encodes information about spin, and that quantum mechanics just doesn't know about these 'hidden variables' yet.

This was interesting as a paradox, but not testable. John Bell (1964) brilliantly made it quantitative and therefore testable. He calculated the probability of correlation in spin between two entangled diverging particles, one measured at a place A at one angle and one measured at a place B at another angle. He calculated this in two ways. First by assuming hidden variables (that the two particles really do have proper physical properties encoded all the time) and this predicts that if the angle between your direction of measurement at A and B are 45 degrees the spins are 1/2=0.5 likely to agree. Secondly, he calculated the same correlation using quantum mechanics, assuming the particles only have real properties when measured, and then he predicted for the same angle a 1/sqrt(2)=0.71 correlation (these numbers depend on the kind of experiment you do, but are, crucially, different at this skew angle!).

All that remained was to do such an experiment and it was done by Aspect et al. (1982) & others. They found by looking at many correlations between photon polarisations (another non-spin way to do the same thing) that the results were consistent with quantum mechanics and not Einstein's hidden variables.

What this means is that if one wants to maintain the idea that there is some physical reality out there that does not depend on the observer, as I think we must (this is called realism) and also maintain free will (so it's not the case that the cosmos knows everything before it happens, in which case: what is the point?) then you must admit that the particles are somehow communicating faster than light, or through time (Cramer, 1986) and therefore these well-observed quantum mechanical experiments are not consistent with special relativity, and the two halves of standard physics do not fit together. I think this anomaly is pointing the way to a complete rewrite of the fundamentals of our fragmented physics, with the finger pointing towards time.

If a kingdom be divided against itself, that kingdom cannot stand - J. Christ (Mark 3:24)

References

Einstein, A., B. Podolsky, N. Rosen, 1935. Can quantum mechanical description of physical reality be considered complete? Phys. Rev., 41, 777

Bell, J., 1964. On the Einstein, Podolsky, Rosen paradox., Physics, 1, 195.

Aspect, A., R. Dalibard, 1982. Experimental test of Bell's inequality using time varying analyzers. Phys. Rev. Letters, 49, 25, 1804.

Cramer,  J., 1986. Reviews of Modern Physics, 58, 647-688 Link