Resisting the end of physics

Things go in cycles, they say. Maybe more in history than in physics. In 600 BC Thales started an era of scientific thought by rejecting the idea that nature is driven by the Greek Gods and argued that it was made of water. This idea was more incisive than it seems at first sight, because unlike every theory that preceded it, it was testable. This great tradition of Greek science continued for seven centuries and included such greats as Aristarchus who suggested the Sun-centred Solar system and Hero with his steam engine (AD 100).

The death blow for Greek astronomy occurred seven centuries after Thales, when Ptolemy in 150 AD used the new tool of geometry, to make a complex Earth-centred model using many oscillating circles (epicycles) which worked well enough to fit planetary motion, for the wrong reasons, as it is easy for complex systems to do. After Ptolemy 1200 years of intellectual darkness descended (despite a few brief flashes in the dark). Of course, it was not all poor Ptolemy's fault since the zeitgeist was moving away from science as well, he was more like a symptom than a cause, but the effect of the epicycles on human thought was dulling.

Scientific enquiry started again 1200 years later around 1300 AD when William of Occam realised that complex models are false friends, and can easily be right for the wrong reason, and proposed Occam's razor (keep it simple). 'Roger' Bacon (thanks qraal) then supported the importance of experimental evidence. Humankind was finally self-correcting and after people like Kepler, Galileo and Newton applied logic (maths) to this reawakened scientific mindset a revolution soon followed.

Now seven hundred years after Occam and Bacon, physics is in danger once more. This time from dark matter, which is just as insidious as Ptolemy's epicycles: a complex fudge to allow an old theory to fit new data. Physicists have used data from galaxy rotation and the new tool of computers to work out what ad hoc complex distributions of invisible stuff will allow the old theories to fit the newly-observed galactic rotation and in so doing have backed themselves into a dark corner it'll be hard to get out of. Specifically, it is unsatisfactory because:

1. Dark matter is ad hoc. It is added to the cosmos by definition to make general relativity predict the data, so, like the epicycles, it inverts the scientific method of changing theories to suit facts, and changes uncheckable 'facts' to suit the theory.

2. It is complex. Rather like the epicycles, it has so many versions and so much flexibility that it is possible for it to appear to work, and yet be absolute rubbish.

3. Mainstream astrophysics must now claim that 95% of the cosmos is made of dark stuff and their model therefore predicts only 5% of the cosmos. If the Met Office only had a 5% success rate I think they'd be revising their model.

4. Dark matter is often presented in the articles I read as doubtless fact, always a danger sign.

5. Popper: any theory that is not falsifiable is not scientific. Dark matter is not falsifable. If they don't find any tomorrow they'll ask for funding to look in a different regime, as has happened many times.

My point is that if dark matter is allowed to absorb almost all the physics funding, then it will stop progress in the same way that Ptolemy's epicycles killed Greek astronomy. It is right on cue as well, roughly seven centuries after Roger Bacon and William of Occam restarted the scientific process. We need to look back at the mindset they had: take no-one's word for it, keep it as simple as possible, look at the data without prejudice, disregard received opinion. The opposite to today's mainstream.

Observations used by Galileo to prove the Sun-centred theory which could have saved Aristarchus' model much earlier, are the phases of Venus. In Ptolemy's Earth-centred Solar system model, Venus could never be behind the Sun, so could never be fully illuminated (see the first reference below). It should have always shown a crescent. In reality, Venus shows phases, sometimes full, sometimes crescent, supporting a Sun-centred model. These phases are just about visible to the naked eye and had been noticed, it is thought, by the Babylonians (Venus has horns they said). Aristotle was sensibly susceptible to data: he had decided the Earth was round by looking at the curved shadow of the Earth during a lunar eclipse. Just imagine if he'd studied the phases of Venus? Being swayed by observation he may well have opted for a heliocentric theory and erased 1200 years of human stagnation. We might be settling Tau Ceti now..

More to the point, what observations in our time unambiguously discredit dark matter? The problem is that dark matter's adjustability (like the epicycles) means it is not easily falsifiable, but there are some data that embarrass it, eg: the anomalous spin of globular clusters which are too small to have dark matter, the alignment of quasars, the critical acceleration in galaxies, the overall agreement of lots of anomalies with MiHsC. Acceptance of these observations at this point may well save us from a 1200 year dark age.

Send any further such observations to the Seldon project, planet Terminus, or, failing that, post a comment below :)

References

Venus reference: http://astronomy.nmsu.edu/geas/lectures/lecture11/slide02.html

Asimov, I., 1951. Foundation. Gnome Press.

The Magellanic Clouds and MiHsC

The Large and Small Magellanic clouds (LMC and SMC) are galaxies just outside the Milky Way, named after the explorer Magellan. These minor galaxies appear to be gravitationally bound to our Milky Way galaxy because they have left a trail of debris behind them, called the Magellanic stream, that curves around in a way that seems to show that they are orbiting our galaxy, see the schematic below:

However, as for almost every orbit on a cosmic scale (galaxy clusters, disc galaxies, dwarf galaxies, globular clusters, Proxima Centauri) the observed orbital velocity is so high that the orbiting mass should break free and zoom off to infinity. The observed orbital velocity of the LMC around the Milky Way is 378 km/s (Kallivayalil, 2013). If we assume Newtonian physics and that the Milky Way has only baryonic (normal) matter, this predicts an orbital speed v = sqrt(GM/r), where G is Newton's gravitational constant, M is the Milky Way's mass and r is the radial distance. This predicts that the maximum orbital velocity that the LMC can have without breaking away is 75 km/s. Oops. So, the LMC should have broken away, but the Magellanic stream suggests it hasn't.

If we assume the usual amount of dark matter in the galaxy, so boost the galactic mass by a factor of ten by adding an invisible and unexplained new kind of matter, then this predicts a maximum orbital velocity before breakaway of 237 km/s, so the LMC should still break away in contradiction to the Magellanic Stream.

MiHsC says that because of its low acceleration outside the galaxy, the LMC has lost some inertial mass and it predicts the following orbital speed, the second term being due to MiHsC:

v = sqrt(GM/r + 2c^2r/Theta)

where c is the speed of light and Theta is the Hubble scale. The MiHsC maximum speed for LMC boundedness is

v = 967 km/s

The observed orbital velocity of the LMC is 378 km/s, so from these examples you can see that MiHsC predicts that the LMC is bound to the Milky Way and is consistent with the observation of the Magellanic Stream that seems to show a bound past trajectory for it. Of course, you can mess around with dark matter arbitrarily till you get the answer you want, but that arbitrariness is deeply abhorrent.

References

Kallivayalil et al., 2013. http://arxiv.org/abs/1301.0832

McCulloch, M.E., 2012. Testing quantised inertia on galactic scales. Astrophys. Space Sci., 342, 575-578. http://arxiv.org/abs/1207.7007

Singularities forbidden?

I usually avoid discussing things like the invisible interiors of black holes, since any predictions are not directly testable, but there is one component of black holes that has been solidly observed and is unexplained: relativistic jets, and these past few days I've realised that, as well as a minimum, MiHsC predicts a maximum acceleration that might get rid of black hole singularities in a way that could be tested by predicting these jets.

I've already shown that MiHsC predicts a minimum acceleration for nature similar to the size of the observed cosmic acceleration (McCulloch, 2010). To recap: MiHsC assumes that inertial mass is caused by Unruh radiation (a radiation seen by objects that accelerate) and that only Unruh waves that fit exactly into the Hubble scale are allowed (since partial waves would reveal what lies behind the horizon: a logical impossibility). The wavelength (L) of the Unruh radiation seen increases as an object's acceleration reduces, and is given by L = 8c^2/a, where a is the acceleration. At tiny accelerations the Unruh wavelengths stretch so that a greater proportion of the waves do not fit within the cosmos (width of cosmos W = 2.6x10^26 metres wide), and at an acceleration of a = 8c^2/W ~ 7x10^-10 m/s^2 no Unruh waves can fit at all. The point is that before an object moving out into deep space manages to achieve this tiny acceleration the MiHsCian collapse of its inertial mass boosts its acceleration. The result is that its acceleration (relative to other matter) can never drop below 7x10^-10 m/s^2. This explains the recently-observed cosmic acceleration.

The Hubble scale is one horizon beyond which we cannot see, another obvious one is the tiny Planck scale (1.6x10^-35 m), so it makes sense to say that Unruh waves shorter than the Planck scale cannot exist (again using Mach's philosophy that only things that can be seen in principle can exist) and so it should be impossible in MiHsC for accelerations to be so large that the Unruh waves are shorter than the Planck scale (lp). Since the Unruh wavelength = 8c^2/a > lp this means that a < 8c^2/lp so a < 4.5x10^52 m/s^2.

The great Sakharov (1966) predicted a similar maximal acceleration, also using Unruh radiation, but without connecting it to inertial mass. Also Caianiello (1984) predicted a similar size of maximum acceleration in a very different way: starting from the uncertainty principle. This maximum may be testable on Earth: Papini (1995) have suggested that light resonating in cavities might be used to generate accelerations this large and that type-I superconductors could experience accelerations as large as this already.

Now back to the black holes. Non-rotating black holes have the problem that general relativity embarrassingly predicts that they have infinite-density singularities at their centres. MiHsC changes this dramatically because it suggests that at soon as the acceleration reaches the maximum near the centre the inertial mass will collapse. I can't picture what such a collapse would do yet, but it is interesting because the physics will somehow have to adjust to keep the acceleration below the maximum (smoothing the singularity) and the energy released could power the unexplained relativistic jets.

References

Caianiello, E.R., 1984. Lett. Nuovo Cimento, 370.

McCulloch, M.E., 2010. Minimum accelerations from quantised inertia. EPL, 90, 29001. arXiv

Papini G., A. Feoli, G. Scarpetta, 1995. Phys. Lett. A., 50.

Sakharov, A.D., 1966. JETP Lett., 3, 288.

Two body thought experiment

Imagine there are two masses, alone in the cosmos. We could call them A and B but I'm tired of Alice and Bob, so let's call them Amy and Sheldon and let's assume, that Ernst Mach was right and that they cannot deduce their acceleration relative to that unmeasurable concept 'absolute space', and can only deduce their acceleration with respect to each other. How romantic! Here they are, and I'm assuming they're wearing futuristic transparent plastic shields (a la Galaxy Quest) to keep them alive in space:

Now let's imagine that Sheldon has a jet pack. It's just the kind of thing Sheldon would have in such a circumstance. Now he fires it and accelerates to the right with respect to Amy. Physics sees this relative acceleration and decides to form a Rindler horizon to Sheldon's left and according to MiHsC this damps the Unruh radiation on the left side of him so he feels more radiation pressure from the right than the left and that pushes him back a little against his acceleration to the right. "Oh, yes", drawls Sheldon, "that's Mike's quaint little explanation for inertia isn't it? I deduce that Mike's writing this story". Very clever Sheldon, but what about Amy? Physics sees Amy accelerating to the left with respect to Sheldon and puts a Rindler horizon to Amy's right which damps the Unruh radiation there and drags her to the right. Oddly enough, Amy is now following Sheldon's motion! "This is very annoying" thinks Amy since she's trying to play hard to get (difficult enough with Sheldon already!), but she is willing to admit, being a member of the fair sex, that this is logical in the MiHsCian world.

What all of this means is that when you consider Mach and MiHsC, and you have two bodies side by side in an empty universe. If you move one, the other will move to follow it. If you have three bodies though, it won't be the same since the mutual accelerations are now more complex, so that if Howard and his turtleneck was there as well, then Amy would be less sensitive to Sheldon's movements and could play hard to get more successfully. This is what is predicted by MiHsC for this contrived situation.

So where's the evidence? Well, in our far more complex world it is difficult to set this experiment up, but in my opinion an inkling of this occurred when Martin Tajmar span his supercooled disc and a nearby accelerometer moved with the disc without frictional contact, rather similar to the way that Amy moved with Sheldon in the thought experiment. Indeed MiHsC predicts these Tajmar results pretty well (McCulloch, 2011). This effect is likely to be more obvious on a cosmic scale, since objects in deep space are closer to being lone masses, and it has been found recently for example that quasar and galaxy spins are aligned.

References

McCulloch, M.E., 2011. The Tajmar effect from quantised inertia. EPL, 95, 39002. arXiv