I've suggested (& published in 21 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

Sunday, 30 December 2012

Minority Report


I've been trying to put some information about MiHsC onto the wikipedia pages for "Dark Matter" and "Galaxy Rotation Curves" and have been deleted by anonymous editors because of "undue weight". I don't see five lines about MiHsC among several pages about dark matter as being undue weight. MiHsC is a far better theory than dark matter. Both hypotheses fit the data but dark matter has infinite adjustability: you can add dark matter where you like to make general relativity fit the galaxy rotation data, so it is not surprising it fits, whereas MiHsC has no adjustable parameters so it is surprising that it fits.

Another complaint of the anonymous was that MiHsC is the view of a tiny minority (ie: me). I'd like to point out that scientific progress does not work by democracy, and certainly not by committee, but I have been through the peer-review process. At least let peer-reviewed new ideas be discussed, otherwise what is the point of it?

Anyway, I here reproduce the text I wrote for the dark matter and galaxy rotation curve pages, in the sections on: alternative explanations for the galaxy rotation problem:

Another possible explanation is Modified inertia due to a Hubble scale Casimir effect (called MiHsC, or quantised inertia). This model assumes that inertia is due to Unruh radiation and that the waves of this radiation have to fit exactly within the Hubble scale, like the waves between the plates in the Casimir effect. MiHsC predicts a new loss of inertial mass for very low accelerations, since the Unruh waves become long and a smaller proportion fit within the Hubble scale. The predicted loss of inertia for stars at the edges of galaxies means that they can be pulled into a bound orbit even by the visible matter of the galaxy, and MiHsC predicts the observed rotation curves correctly (within error bars) without dark matter, and has no adjustable parameters.

References:

McCulloch, M.E., 2012. Testing quantised inertia on galactic scales. A&SS, 342, 2, 575. http://link.springer.com/article/10.1007%2Fs10509-012-1197-0
http://arxiv.org/abs/1207.7007

Wednesday, 19 December 2012

Comments to NASA

A few months ago, NASA asked for comments from the general public. One of their questions was: What is your understanding and opinion of NASA's current vision, mission and strategic direction? If you think NASA's vision, mission and strategic direction should be different from the above, please state what they should be and why. Part of the answer I sent in, slightly edited, was this:

I think the NASA vision ("Improve life here, extend life to there, and find life beyond") should have the 'extend life to there' first, and 'improve life here' second, not because the latter is unimportant, but because NASA's unique goal should be the outwards push. This push will improve life here eventually since science and technology are always spurred to develop by people coping with new environments, but other government bodies exist primarily to look inwards. NASA alone is pushing out, and that shouldn't be diluted in my view.

NASA is developing a system to take humans to target an asteroid by 2025 and Mars by the 2030s. I think the target should be more immediate (within ten years), bold but achievable, and most important: permanent. By permanent I mean the infrastructure that is set up should be permanent and can grow with time, rather than being doomed to destruction like the ISS or the shuttles (great achievements, but they fade rather than growing). There are limits to growth on an asteroid. The easiest target that fits these criteria is a permanent base on the Moon. Of course, NASA has been to the Moon before, but I'd like to point out the difference between the abortive Viking visits to America and the Pilgrim fathers who settled and 'grew' into something new that contributed to human culture and science (and unfortunately displaced the native Americans, but happily there's no one to displace on the Moon). So I'd suggest a permanent base on the Moon: and Mars later on, since it is little better in terms of livability and too far away for easy travel and interaction. These goals would be more achievable if NASA utilised companies like SpaceX who have proven their efficiency.
 
Also, I think NASA needs to start thinking more about game changing technologies for Earth-Moon-Mars travel and fund people to look into it (ahem). Further, making NASA independent of political control with a fixed budget would enable it to follow a steadier course. Decisions are sometimes not being made logically by scientists, but emotionally by politicians to please states or groups, and this decreases efficiency.

Wednesday, 28 November 2012

The Importance of Being Empirical


The problem with mainstream theoretical physics today is a lack of connection to reality. String theory or loop quantum gravity, for example, are like constructed virtual realities that bear no direct relation to the real world. The proof is that neither of the theories are testable: they cannot be disproven, and this has given them a longevity they do not deserve.

There is a related trend in modern art and this is interesting because both art and science are ways of modelling the world. In a similar way, art used to be testable. An artist draws a face or and lanscape and there is an objective test. Does it look like the real thing? If so, we can say that the artist has skill. Then the camera came along and this skill became obsolete. Art reappeared in a form detached from reality: abstract art. I won't attempt to judge modern art, but a science detached from reality is a disaster, and takes us back before Empiricism and Roger Bacon!

String theorists may say it is not their fault that the theory cannot be tested. But it IS their fault. If they are scientists they need to work on theories that are testable. Either devise a test or forget the theory and start looking at the real world. This used to be the first rule of science, but it has been allowed to lapse. It reminds me of a comment I once read about ancient Greek science when it had passed its peak and humanity was heading for the dark ages: "Speculation ran way beyond the testable and dwindled into metaphysics" (McEvedy, 1961). I hope we are not drifting into a dark age where smug scholars in ivory towers discuss uselessly what came before the big bang, when they can't explain how local galaxies behaved last week, or even why the turbulence in a pipe starts when it does. The best progress has always come from a little thought applied to interesting observations: a prism experiment lead to a better theory of light, a view of Jupiter's orbiting moons through a telescope inspired heliocentricity and gravity, and the null result from the Michelson-Morley experiment lead to relativity.

On a positive note, I worked for ten years at the UK Met Office, in the ocean forecasting section (not climate research) and the ethos in this Ocean Forecasting section and also in the NWP (Numerical Weather Prediction) was healthy, because the ocean or atmosphere models had to forecast data that was continually coming in from satellites, weather stations and ocean buoys in the real world, so there was a constant check from reality to test and improve the models. This is the best way to do science: lots of data, some anomalies, and a little thinking applied.

I'll leave the last word to Sherlock Holmes' creator: "It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts." - Sir Arthur Conan Doyle.

References:

McEvedy, C., 1961. The Penguin Atlas of Ancient History. Penguin Books. (Page 92).

Sunday, 25 November 2012

Predictability and Understanding

I've drawn a schematic that classifies how I see various physical theories. The y axis shows how successful the theory is at predicting the real world, or its testability. For example quantum mechanics (QED) can be tested and is very accurate, whereas Lovelock's Gaia Theory is not very predictive or testable, yet, and string theory is not at all. On the x axis I have Understanding, which is supposed to be a rough measure of whether the theory comes with a physical mechanism that explains intuitively how it works. So, thermodynamics is well explained as being due to the statistical motion of atoms, but the onset of turbulence in fluid dynamics is not at all understood:
The top left box is for empirical theories which predict the world quickly, but without the need for an understanding. They usually have adjustable parameters. Many models have been born in this box and end up migrating to the right into the physics box when they are understood better, eg: quantum mechanics originated from Planck's empirical formula, with the adjustable parameter being Planck's constant.

On the top right is the physics box, which mixes predictability with some understanding. The ideal physics is in here. Ideal physics can predict nature, but also includes an intuitive mechanism which helps us to extrapolate the ideas to other parts of nature. I've listed thermodynamics and special relativity very high on both axes since the mechanisms for both are well understood and they both make testable predictions that fit nature.

On the bottom right is the box for philosophy which is all about understanding, without necessarily a need for directly predicting details of the real world. Some beautiful ideas that end up as part of theories start off here, like Mach's idea about observables which helped to produce special relativity.

I'm not sure what to call the bottom left quadrant, but here the theories are neither well understand, nor do they make any testable predictions about nature. This is the worst kind of model: untestable. The kind that Pauli would have called: "Not even wrong". Most of contemporary theoretical physics is here. This is probably the case in every epoch: the only theories we remember from the past are the better ones that survive. These tend to be born in the fertile empirical box and migrate slowly to the right, sometimes with a dash of insight from the philosophical box.

Sunday, 11 November 2012

Explaining MiHsC: Whirling a Ball around on a String


Imagine you are standing there in your garden with a ball tied to a string. Slowly you whirl the ball around you so it is pulled outwards. What it pulling it outwards? No one understands the mechanism, but this effect is called inertia. The idea is that objects tend to keep going in the same direction at the same speed until something pushes on them. The ball has inertial mass so it wants to go in a straight line, but you and the string are pulling it towards you. A balance is reached: an orbit, until you let go of the string and send your friends running for cover.

Zooming out by a factor of a million million million, galaxies are similar. Balls of fusion (stars) mutually orbiting, with inertia pulling them apart and gravity pulling them together. The problem is that galaxies spin around so fast that the inertia as we know it, should win over gravity and tear the galaxies apart. Yet galaxies remain stably intact. The small amount of matter we can see lit up in fusion (ie: stars) seems to hold all the stars together. How?

In the 1930s a Swiss called Fritz Zwicky proposed that matter that we cannot see is responsible: dark matter. This sounds fair enough, but the dark matter is needed only in the outer edges of galaxies, and no particles have been detected that could provide the very specific new physics, and the extended distribution (the halo), needed to account for the observed galactic rotations. Dark matter is also not a satisfying theory because it is not predictive or falsifiable. Given any galaxy you can add dark matter wherever you want to fit your predicted rotation curve to the one observed.

If we come back to you whirling a ball around in the garden for a minute. Imagine you could whirl the ball so fast it becomes a blur. Surely the string would break under the inertial pull outwards. What if it didn't? Well, you could conclude that the string was made of strong carbon fibre so it can pull inwards without breaking (just like extra matter in a galaxy provides extra inwards pull), or otherwise you could conclude that the ball is hollow and has less inertial mass than you thought. This means it is less inclined to follow a straight line and zoom off, and more easily bent into a curved orbit even by an ordinary string.

Similarly, instead of adding extra gravitational mass to the galaxy, can we reduce the inertial mass of its stars? There is a way to do this using what is called: "Unruh radiation". This is similar to the Hawking radiation you get in a gravitational field, but you see Unruh radiation only when you accelerate. You also see inertia only when you accelerate, so maybe inertia is linked to Unruh radiation.

Unruh radiation is a wave with a wavelength that depends inversely upon the acceleration. At the edge of galaxies the acceleration is tiny and the Unruh waves become so long that a smaller proportion of them can be measured, and Ernst Mach once said that if you cannot measure something you should discard it, and this kind of thinking led Newton to discard Descartes' vortices and led Einstein to discard the aether, so let us say that if the Unruh waves cannot be seen, then they cannot contribute to inertia, so galactic edge stars lose inertial mass in a new way. On galactic "scales" they have lost mass (forgive the pun). A lower inertial mass means the stars can be more easily bent into a bound orbit, even by the small amount of stellar mass we see in the galaxy.

To cut a long story short, such a model, called MiHsC or quantised inertia, works and fits galaxy rotation curves without dark matter (see the paper below). It also does this without adjustable parameters, which means it gives only one answer, and that happens to be the right one.

McCulloch, M.E., 2012. Testing quantised inertia on galactic scales. Astronomy and Space Science. Vol. 342, No. 2, 575-578.
Journal paper: http://www.springerlink.com/content/1778177x0570j647/

Tuesday, 6 November 2012

MiHsC and entropy?


A paper has just been published by J. Gine called "The Holographic Scenario, the Modified Inertia and the Dynamics of the Universe" (see the link below). I haven't understood the two-screen holographic model he is suggesting yet (I always find these so called 'holographic screens' to be very contrived and unnatural), but I found the last section of the paper particularly intriguing (especially eq. 44) because he uses MiHsC :) He takes the usual MiHsC expression for inertia and rewrites it in terms of Unruh temperatures (though in the paper he doesn't quite complete this conversion..) which allows MiHsC to be thought of in a more overtly thermodynamic way. Whether this will prove useful or not I don't know! Gine's paper is here:

http://www.worldscientific.com/doi/abs/10.1142/S0217732312502082?journalCode=mpla

All this thermodynamics reminds me of a thermal experiment I suggested in 2007: the effect of MiHsC on Unruh radiation (disallowing the longer, colder, wavelengths) should also apply to normal radiation, so the energy radiated by a very cold object should be very slighly less than that expected from the Stefan-Boltzmann law. For more details see the last part (around eq. 13) of this paper:

http://arxiv.org/abs/astro-ph/0612599
McCulloch, MNRAS, 376, 338-342.

Tuesday, 30 October 2012

Forks in the Road


Newton had his prism, and knew just what it meant.
Darwin saw some finchs' beaks, differently bent.
Einstein had Lenard's data, Michelson-Morley's too.
Reading these anomalies, they worked out what is true.

The cosmos has an imagination, greater than anyone.
It is difficult to outguess it, so what is to be done?
Rather: set up crucial experiments, like forks in a road.
The direction nature takes, will reveal the cosmic code.

Thursday, 25 October 2012

The Irrelevance of Craziness


There's a interesting discussion going on over at Backreaction over a craziness factor for new theories. The proposal is that one should check how crazy (different to the standard model) is a new theory, and if it is a bit crazy that's good, but if it is very crazy it is bad. As I've said in a few comments over at Backreaction, I think this is misguided, since in my opinion the sole criteria for judging a new theory should be whether it "predicts nature better and is simpler" than the old models. These things can be determined objectively, whereas the agreement of the theory with human expectations is subjective, and should not be used to judge it.

There's a song, by Seal, that contains the line: "but we're never going to survive, unless we get a little crazy", and that's right in my view. The deeper workings of the cosmos probably would seem mad, if suddenly revealed, relative to our quaint conceptions, so our minds are going to have to learn to 'think crazy' relative to our current modes of thought, to understand the universe as we move out into new regimes, as we already do a little to understand relativity and quantum mechanics. Our world view is better than that of the ancient Greeks, but they would see our worldview as bizarre. Plato would have difficulty imagining that people are standing upside down in the antipodes. Who knows what parochial views we are a victim to?

Some will always try to fit the universe into our present notions of sanity, or stay close to them, by adding patches where they can, but this will eventually be inadequate. I'm not saying that we should deliberately try to be crazy, but I am saying that subjective measures like apparent craziness should not be considered when judging theories. Crazy or not, if they predict nature, and are simpler, then let them stand.

There is a pleasure sure, in being mad, which none but madmen know.
- John Dryden.

Tuesday, 23 October 2012

The Star Trek London Convention


This last Sunday I went to the Star Trek Destination London convention. It is only the second Star Trek meeting I have been to, but it was extremely interesting, also when I assess my own reaction to it: I wandered around in awe. There was Chekov (Walter Koenig) walking around smiling broadly with a cap on, Data (Brent Spiner) looking out of this world with his bright white hair, all five Captains in booths, hidden by autograph queues. I paid particular interest to the characters from Enterprise (Bakula, Keating, Mongomery, Trineer). I like that series since in many ways it is more realistic, and closer to home timewise, and I like Scott Bakula's portrayal of Captain Archer, I saw his blond hair and big nose from afar. Archer is less decisive and passionate than Kirk, less Professional than Picard, maybe less caring then Janeway, who I also saw from afar (I haven't seen much DS9), but for me Scott Bakula gave the most realistic portrayal of all the captains of an explorer: someone trying to push the human envelope despite huge obstacles, and trying to work out how to do something right, that has never been done or imagined (note: I had only seen Enterprise Seasons 1 & 2 at this time).

I paid to get the autograph of William Shatner, who I have adored since childhood, and paid to see his talk, which was characteristically entertaining. When asked which film was his favourite he said of course: his own Star Trek V. For this film he'd ordered a rock monster breathing fire, but after paying $250,000 a guy in a monster suit showed up with a couple of rocks on his back and instead of breathing fire he emitted a wisp of smoke that blew away in the desert wind. I've read this story before, but Shatner's telling of it was as white-hot passionate as ever. His final comment was that he'd tried to play Kirk with "Awe and Wonder" at the universe, even when faced with death. I looked down at my four year old son, who was asleep draped across me and my dear wife (who reluctantly, but kindly, accompanied me to the convention). Awe and wonder: that is indeed what the universe deserves... No, Shatner didn't dissapoint me. Earlier in the day I got his autograph, and after thanking him I said I'd written a paper (and submitted it to a journal) suggesting that faster than light travel is possible, but he just said "You're very welcome". He was probably in a daze having thousands of people traipse past his booth.

I was certainly in awe and wonder, but also at my own reaction. I am well aware that these are actors and are paid to pretend to be explorers, so why do they affect trekkies this way? Well, sometimes as children we see a situation that we'd love to be in when we grow up. Like my son, who'd love to drive a train. Maybe Star Trek is like that for humanity (the technically-minded part of it anyway). It is a good future for us, with decent morals, interesting explorations and the possibility of healthy growth, and these actors remind us of this future. We are fooled by it, of course, because it is just imaginary, but we allow ourselves to be fooled, since it makes us happy.

There's a saying by Johnny Cash: "You gotta be what you are. Whatever you are, you gotta be it". I think this means that, while feelings may indeed seem to be based on rubbish or even illogic, if it makes you happy: go with the flow. This is like going with the grain of your internal nature instead of across it. More importantly, feelings can be wise in ways that logic can never hope to follow. The initial impulse for research can be irrational too, and although ultimately logic and data must be shown to agree, it may be true that if we believe in the possibility first, it may just be the thing needed to make it all come true.

Anyway, I had a good few hours wandering around in my irrational nirvana.

Friday, 5 October 2012

Relativity & the GPS


Yesterday I gave my first lecture of term, all about the Global Positioning System (GPS), and managed to cover some very interesting things with the students. For example, special (SR) and general relativity (GR), which is important for GPS satellites which are fast moving, so time slows for them (SR), and higher up in the Earth's gravity well, so time speeds up for them (GR).

To explain relativity, I talked about a couple of mirrors with light bouncing between them to form a clock: say, each bounce is a second. Now if the mirrors move sideways relative to you the light has further to travel along the diagonal, but because the speed of light is supposed to be the same in all reference frames the light can't speed up, so the mirror-clock ticks more slowly for the moving mirrors: time dilation.

As I told my students (who were healthily sceptical of all this!): you might think that the slowness of the clock is just an apparent thing because we are seeing it from afar, but no! This has been tested. Some scientists (Hafele and Keating, 1971) left one atomic clock at home and took one for a ride on a fast and high plane to slow it down and speed it up by relativity. When they brought the clocks back together the effects of relativity were still there. This is amazing, because it means that the slowing down of time, is "real" (whatever that means) and not just apparent. This has a huge implication: that reality is what you can observe. It seems that because it is impossible in our reference frame to ever perceive the clock going at the 'normal' speed, then it doesn't go at the normal speed, it goes at the only speed we can perceive it to go.

Similarly, in MiHsC, the idea is that because we can never in principle measure the longer Unruh waves that don't fit exactly within the Hubble scale, they cannot exist. It's not particularly that we as humans cannot see them (it's not subjective), but rather that they cannot be seen "in principle", a more objective view. I'm suggesting that relativity should be modified very slightly, by MiHsC, based on this kind of thinking. It may seem strange that the world works in this Wycsiwyg (What you can see is what you get) manner, but the cosmos is no stranger to strangeness (sometimes it seems about as sane as a Penrose triangle). The point is that thinking like this does make correct predictions of nature, and that's the important thing.

Sunday, 30 September 2012

Gravity beyond Einstein


Last Thursday I presented a talk at a "Gravity beyond Einstein" workshop at the Institute of Physics in London. First of all, the fact that the IoP's Gravity Group set up this workshop shows that they are open to new ideas, which is great. There were also many talented young physicists there, who I think only lacked the freedom to create, which means the freedom the "break" things, if justified. The impression I got was that the other speakers were trying to get beyond Einstein by bending his field equations using extra terms, tensors & dimensions, but without breaking anything. The resulting theories were full of adjustable parameters, like Ptolemy's epicycles.

Einstein was aware that general relativity (GR) was not the final word (see Surely You're Joking Mr Feynman, page 80, lines 12-14). He spent his last years trying to replace it, but was working without the help of the 'anomalies' (experimental signposts) that he had had before for special relativity (the Michelson-Morley experiment) and quantum mechanics (Lenard's photoelectric experiment). The relevant clues for the next generation theory: the galaxy rotation problem, the supernova data and spacecraft trajectories, only appeared much later in the 1970s, 1980s & 1990s and the replacement of machine-based thinking with information technology has occured recently too. GR is still rather entrenched, but all theories are flawed. They are like mathematical cartoons of nature, not the thing itself, and theorists sometimes forget that.

I think my attitude is better. In my talk I started from an anomalous observation: the galaxy rotation problem, tested a simple new physical principle that has no adjustable parameters (MiHsC) on this problem, obtained good agreement and made further predictions that can be tested.

It is time we had the confidence to replace GR, and that cannot be done by bending it, it must be done at a deeper level. I think MiHsC (quantised inertia) is a step towards that because, to summarise: it agrees with the data without adjustable parameters, it is simple, it makes predictions from parameters that can be fairly directly observed like baryonic matter, the speed of light and the Hubble scale rather than things that cannot be directly observed like dark matter, curved space and extra dimensions, and rather than the old machine-based physics, it points towards a new way of thinking based on information.

For further details see: http://arxiv.org/abs/1207.7007 (Published in Astrophysics and Space Science, online early) and a more accessible account of it is here.

Thursday, 13 September 2012

QI & MoND vs the data: new figure.


Someone helpfully suggested that I should redo the Figure that I published in this paper (in Astrophysics and Space Science) using a vertical log scale, and the result is much clearer and is shown below. This Figure shows the baryonic mass of the astronomical system in Solar masses along the x axis, from the light dwarf galaxies, through gas discs and spiral galaxies and up to galaxy clusters. The vertical log axis shows the rotation speed of the system in km/s. The black circles are the observations (from McGaugh et al., 2010).



















MoND predicts the two dotted lines, but to do this you must "tune" its adjustable parameter (a0) by hand to be 1.2x10^-10 m/s^2 or 2x10^-10 m/s^2. Quantised inertia (MiHsC) predicts the dashed line without any adjustable parameters. See here or the preprint for more details. So both MoND and MiHsC agree with the data within its uncertainty but MoND has to be "tuned" to fit, whereas MiHsC works as it is.

Monday, 20 August 2012

Quantised inertia in galaxies


This is a short summary of a paper I have just published in Astrophysics and Space Science (here). Galaxies and galaxy clusters have been seen to rotate so fast that the (inertial) centrifugal forces should tear them apart. Yet, they sit there obviously a stable collection of bound stars. Therefore, the small amount of matter we can see lit up in fusion (ie: stars) seems to hold them together. How?

Some have proposed that matter that we cannot see is responsible: dark matter. This sounds fair enough, but dark matter is needed only in the outer edges of galaxies, and no particles have been detected that could provide the very specific new physics, and the extended distribution (the halo), needed to account for the observed galactic rotations. Dark matter is also not a satisfying theory because it is not falsifiable. Given any galaxy you can add dark matter wherever you want to fit your predicted rotation curve to that observed.

Instead of increasing the gravitational mass in the galaxy to hold it in by force, one can also decrease the inertial mass of the stars in it to make them more easily bind. I have suggested a model called "Modified inertia due to a Hubble-scale Casimir effect" (MiHsC), or quantised inertia (QI) for short, that does this. In QI the inertial mass decreases in a specific new way for low accelerations. Stars at the edge of galaxies have low accelerations, so QI predicts they have less inertial mass, for the same gravitational mass. A lower inertial mass means the stars can be more easily bent into a bound orbit, even by the small amount of stellar mass we see in the galaxy. In the paper I have shown that QI predicts the rotation speeds of galaxies and galaxy clusters without needing any fitting parameters or dark matter. QI also predicts the change from the Newtonian behaviour in the galactic centre, to the anomalous rotation near the edge.

The main controversy with QI is that it violates the equivalence principle (very slightly), but as I have discussed in another paper (in the discussion of the paper here) this violation could not have been detected by the torsion balance experiments that have been used to test this principle so far.

The journal paper is here, and an arxiv preprint is here.

Friday, 27 July 2012

Quantised inertia on galactic scales


I'm pleased that my paper (Testing quantised inertia on galactic scales) has just been accepted by the journal Astrophysics and Space Science. I used the data published by McGaugh, Schombert, de Blok and Zagursky (2006) listing the baryonic mass and circular velocity of dwarf galaxies, spiral galaxies and galaxy clusters. In the paper I show that MiHsC (quantised inertia) predicts the observed circular velocity of all these structures (within the uncertainties) from their baryonic mass only (ie: without dark matter).

In more detail: MiHsC overestimates the circular velocity of galaxies (but still agrees within the error bars) whereas MOND agrees better with galaxies, if you set its adustable parameter (a0) correctly. On the other hand MiHsC agrees better with large galaxy clusters, where MoND has always had trouble, and a very important advantage of MiHsC is that it doesn't have any adjustable parameters. The paper is on the arxiv here.

Monday, 9 July 2012

Beyond the Pail: Mach's Principle


If you spin a bucket (pail) of water, initially only the bucket spins, the water remains static and its surface flat. Soon, because of friction, the water spins too, and piles up around the edges, because inertia means it moves in a straight line, and outwards from the spin axis. Eventually, a concave water surface and a pressure gradient forms that balances the inertial tendency outwards. What does this inertial force depend upon? Not, noticeably, on motion relative to the bucket wall, because at first when the fluid was moving relative to the wall there was no curve in its surface. Newton concluded that there was only a curve when the water was moving relative to absolute space. Later, Berkeley and Mach said there was no such thing as absolute space (Einstein based relativity on this) and that the spin has to be measured relative to something observable like the fixed stars, so that a pail spinning in endless emptiness would not experience inertial forces at all. Einstein called this idea Mach's principle: inertia here is due to masses there. Considering the fixed stars also allowed Mach to wonder what would happen if Newton's bucket was static, but the fixed stars span around it. He said: "no one is competent to say how this experiment would turn out." (Bradley, 1971). Would the surface of the water curve or not?

MiHsC works in a similar way to Mach's Principle and states that the inertia of an object here increases with its acceleration relative to other masses there. It is predictive, so it has something new to say about Newton's bucket: if the fixed stars were whirled around it, there would be the same mutual acceleration between, each part of, the water and the stars, that occurs when the water spins and the stars are fixed. So, according to MiHsC, the inertial mass of the water would increase in the same way in both cases. By MiHsC & the conservation of momentum, in the bucket-spin case the initial spin would be slowed by the gain in inertia, and in the fixed-stars-spin case the water would start to rotate following the stars.

For observational evidence I can cite the flyby anomalies and the Tajmar experiment. With the flyby anomalies, small observed jumps in flyby spacecraft speed can be explained by MiHsC as being due to changes in the inertia of the craft as they accelerate relative to all the matter in the spinning Earth (McCulloch, 2008). In Martin Tajmar's experiments, a ring (instead of the fixed stars) was spun around a gyroscope (in a cold environment to purge all other accelerations), and the gyro followed the rotation of the ring (slightly), just as predicted by MiHsC: the gyro gains inertial mass when the ring accelerates, and to conserve momentum it has to spin with the ring (McCulloch, 2011). In Tajmar's experiment, there was also a parity violation which is predicted by MiHsC as being due to the Earth's spin relative to the fixed stars. The success of MiHsC in predicting these cases, shows that in low acceleration environments (cold or deep space) Mach's Principle may have been glimpsed.

Bradley, J., 1971. Mach's philosophy of science. The Athlone Press.
McCulloch, M.E., 2008. Modelling the flyby anomalies using a modification of inertia. MNRAS, 389(1), L57-60. http://arxiv.org/abs/0806.4159
McCulloch, M.E., 2011. The Tajmar effect from quantised inertia. EPL, 95, 39002. http://arxiv.org/abs/1106.3266

Thursday, 28 June 2012

Cosmic acceleration from MiHsC


Newton's first law, the inertial one, says that the default acceleration is zero, so, in a vacuum, objects move happily along at constant velocity until something external pushes on them.

MiHsC or quantised inertia (see the references below) predicts something slightly (usually undetectably) different: that the default acceleration is non-zero and equal to 2c^2/Theta where c is the speed of light and Theta is the Hubble scale, so 2c^2/Theta = 6.9*10^-10 m/s^2. This is tiny, but is equal to the recently-observed cosmic acceleration that some have attributed to 'dark energy', and model by grotesquely adding a cosmological constant term to Einstein's field equation. I'll try and explain here how MiHsC predicts the observed cosmic acceleration using just its two assumptions, which are:

1) Inertia is caused by Unruh radiation (a kind of wave) and..
2) ..these waves must fit exactly into the Hubble scale (like a Hubble-scale Casimir effect or cosmic seiche).

The thing about Unruh waves is that as an object's acceleration decreases the Unruh waves it sees get longer. With a boundary this becomes significant. If you make small waves in a bath with, say, an electric toothbrush, then most of the little waves will propagate, but if you make large waves with a paddle, then you'll have to get the wavelength exactly right or the waves won't fit. The point is that for longer wavelengths, a smaller proportion of the waves are allowed because of the boundary condition: this resonant behaviour is called a seiche in oceanography and happens a lot with waves in lakes and harbours. This implies straight away that Newton's first law (default acceleration = 0) won't quite work in MiHsC, because if the acceleration is zero, or close enough to zero, the Unruh waves are as large or larger than the observable universe, ie: unobservable, and as Mach said: if it can never be observed, forget it! (to paraphrase).

In MiHsC, the same process as in the bath works with objects moving into deep space. As they move away from other gravitating matter their acceleration drops. Therefore, the Unruh waves they see lengthen, and a greater proportion are disallowed, so that the inertia of the object eventually decreases very fast, making it easier to accelerate even with a distant gravitating mass, and this stabilises the acceleration at a minimum of 2c^2/Theta. Happily, this is the acceleration that has been seen in the deep cosmos. It has been attributed to the vague concept of dark energy, and modelled by adding the cosmological constant term (an adjustable parameter) to Einstein's field equations, but MiHsC predicts it far more easily, and without any adjustable parameters.

References:

McCulloch, M.E, 2010. Minimum accelerations from quantised inertia. EPL, 90, 29001. http://arxiv.org/abs/1004.3303
McCulloch, M.E., 2007. The Pioneer anomaly as modified inertia. MNRAS, 376, 338. http://arxiv.org/abs/astro-ph/0612599

Monday, 25 June 2012

Globular clusters: crucial experiments?


I think that the way to approach physics is not to aim to invent beautiful theories, but to look for the data that shows the way. One of the sign-post papers that happened to influence me in this way was: Scarpa, Marconi and Gilmozzi, 2006, although I've read similarly clear ones by, eg: M. Milgrom, S. McGaugh & X. Hernandez.

Scarpa et al. make the point in their introduction that Newton's laws have never been tested at the tiny accelerations that exist at the edge of galaxies and that "deviations from Newtonian dynamics are always observed when, and only when, the gravitational acceleration falls below ~10^-10 m/s^2 as computed considering only baryons". They go on to state that it is agreed that dark matter cannot affect things on the small scale of globular clusters (dark matter haloes are large and smooth), so they looked at three globular clusters and showed that, indeed, below the critical acceleration (from the mass in the cluster) they deviate from Newton, just like larger galaxies. This suggests the presence of new physics rather than dark matter.

They also make the point that the external gravitational field, from the larger galaxy, acting on the globular clusters is above the critical acceleration, but the non-Newtonian behaviour is still seen. This points away from MoND where dynamics depend on the total acceleration, and points towards MiHsC where it is the local mutual accelerations that matter.

Scarpa et al. isn't perfect, only three globular clusters were analysed, but I'd like to express my appreciation to all those, like them, who risk unpopularity to base their conclusions on direct observations of nature, eg: M. Milgrom, S. McGaugh, X. Hernandez, J. Anderson, M. Tajmar, CERN (especially the OPERA team).... Observing new regimes is hugely risky, but is the only way to get to new physics.

Saturday, 9 June 2012

Hartle, Hawking & Hertog's first sentence.


I should say first, that I have found Hawking's earlier work to be useful (ie: Hawking-Unruh radiation). However, I do not agree with the attitude to science represented by his recent attempt, with colleagues Hartle and Hertog, to make 11-dimensional string theory compatible with a very abstract version of reality, by adding even further complexity to string theory (they add a so-called Escher space). See: arxiv:1205.3807v2 (Accelerated expansion from negative Lambda, Hartle et al., 2012).

To make my point I can start with the first statement they make in their abstract: "Wave functions specifying a quantum state of the universe must satisfy the constraints of general relativity". The implication is that general relativity (GR) is the truth, and everything else must be measured against it. Well, whether or not GR is the final truth, and I am pretty sure it is not, what should have been said is something like: theories specifying the state of the universe must satisfy the constraints of observational data. This seems like nit-picking, but is not. It is fundamental that the data must always come before the theories.

GR only agrees with galaxy rotation data if, typically, 10 times as much matter as can be seen is added ad-hoc in an unphysical way to the galaxies to make it fit. This seems to me to be an example of theorists adding complexity to a theory (adding dark matter and the new physics needed for it) in a desperate attempt to save it (like Ptolemy's epicycles were invented to help geocentric theories fit the observed planetary ephemerides). Sure, the idea of dark matter worked in the case of Neptune, whose existence was postulated to fit the motion of Uranus to Newtonian gravity, but this was the addition of a small amount of normal matter in the plausible shape of a planet, whereas dark matter needs the addition of 10 times as much matter as is seen, in a new form and with new physics to go with it to explain its bizarre halo-like configuration.

The physicist's focus should always be on the data and not the theory, which is why I am so keen to critise the first sentence of Hartle et al.. In contrast, MiHsC is not a finished theory yet, but I have developed it from the bottom up, by looking at messy anomalous observations and disregarding most of the existing top-level theories. As a result, MiHsC is simple and can explain cosmic acceleration, dwarf and disc galaxy rotation (I've just submitted a paper on this), the flyby anomalies, the Pioneer anomaly (although so can Turyshev et al.'s complex thermal model), and the Tajmar effect (albeit unrepeated experimentally), without the need for adjustable parameters, extra dimensions, or Escher space.

Friday, 1 June 2012

Against Dark Matter: needs new mass and new laws


To me, the dark matter hypothesis seems to be rather like Ptolemy's epicycles, Descartes invisible Vortices or the aether: a fudge. One question is: if so-called dark matter only feels gravity, then what keeps it from collapsing in on itself? The collapse under gravity of ordinary matter can be arrested because, to give one example, as matter is squeezed, temperatures rise, fusion begins, and an outward pressure appears (the exchange of momentum is due to the electromagnetic, EM, force) and a balanced system, a star, is formed. This could never happen with dark matter (DM) since it does not feel the EM force and so it can't be held up by pressure (but despite this, they say it can still lose kinetic energy, and collapse inward, via three-particle collisions). To allow general relativity to predict galaxy rotation curves correctly huge amounts of dark matter must be assumed to remain in an uncollapsed state in a huge sphere (halo) around a galaxy's visible matter. The gravitation forces on this halo would be ten times that due to the baryonic matter and the halo is not spinning to provide inertially-supportive forces (no flattening) so the dark matter should have collapsed quickly. To be held out there, gravity must be assumed to be balanced by some outward force.

This force can't be assumed to be the EM force (pressure) or the strong force because DM can't possibly feel them (if it did, experiments would have seen it) and the weak force is limited to very short ranges of ~10^-17 metres.

What keeps the proposed DM in an uncollapsed state? The physics does not exist to do it. People often refer to MiHsC as "exotic" physics, but it seems exotic physics is unavoidable. Either invent a new kind of invisible (dark) matter and new physics to go with it, or (neater & simpler) keep matter unchanged and modify only the physics. MiHsC is an example of the latter approach, and models galaxy rotation like this.

Saturday, 19 May 2012

Launching with physics instead of chemistry.


I've just seen the attempted launch of the Falcon 9 rocket (their next try will be on Tuesday) and I think SpaceX is the most exciting thing to come out of the USA since the Apollo program. The UK's SKYLON project looks potentially bold too and I wish these, the consistent Russian manned space program, the growing new Chinese program, and other space programs the best of luck, but seeing launches like this I always think there must be a way to launch to space without chemistry, and maybe there is using MiHsC:

If inertia is due to Unruh radiation then it should be possible to modify the inertia of objects by interfering with, or enhancing, the Unruh radiation they see. Then, as their inertia changes, the conservation of momentum should cause them to move. I proposed one test of this at the end of this paper (published in EPL, 90, 29001, 2010, see the section just before the Conclusions):

Since then I have tested MiHsC on some experiments done by Tajmar (the Tajmar effect), by assuming (as above) that the sudden acceleration of an object (a ring in this case) near to a gyroscope changes the Unruh waves it sees, and therefore its inertia, causing it to move to conserve momentum. MiHsC predicted the anomalous observations very well: see this paper (published in EPL, 95, 39002, 2011). I discuss the idea of launching using inertia here (unfortunately, this abstract has been deleted, email me if you want a copy).

Of course, getting funding to test this is going to be difficult, but I think it would be worth it, since it could provide a new method of launching without dangerous high explosives.

Friday, 11 May 2012

In Between the Models.


Yesterday I attended a talk here at UoP by an academic from Swansea. He was a nice chap who gave a brilliant talk on a subject he passionately believes in: string theory and the AdS/CFT (Anti-deSitter Space/Conformal Field Theory) duality. So while being tremendously impressed by him, I was unimpressed by string theory.

The summary is that a unbelievably complex string theory in 11 dimensions looks rather like a 4 dimensional Conformal Field Theory without gravity. At the end of his talk I asked him whether "it might be just a meaningless coincidence that 11-d string theory looks a bit like 4-d CFT?' and I told him that an experimental test was needed somewhere. He said that when you actually do the calculation the similarity is so miraculous, even from such a complicated theory, that it must be right. Not necessarily! Maybe it is just coincidentally how the maths works out in the collapse from 11 dimensions to 4. Maybe theorists have now played around with so many 11-d string models that they have finally found one that by accident looks like the 4-d CFT model? Ptolemy's epicycles were very complex and reproduced the observed behaviour, but were wrong. To do physics, string theorists have to suggest an experimental test whose behaviour would be different depending on whether string theory is true or not, otherwise it is mathematics, not physics.

Mathematics is essential for setting up predictive models, but is just a human invention, a derived thing, and I don't believe you can get paradigm shifts in physical theory by just "mixing up" old mathematical models. In the same way, there are probably an infinite number of concepts whose description lies outside the words we have, and you'll never get to them using existing words. Something non-verbal from outside is needed as a initial guide: from observation & intuition and then words (or maths) can be invented to describe them.

Unfortunately, the uber-mathematical approach is the fashion in theoretical physics right now, and it always reminds me of a quote about the death of ancient Greek science: "speculation went way beyond the testable, and into metaphysics" (words or maths with no input from nature) , so to avoid this I always try to think about anomalous observations, which is very difficult, messy and even misleading sometimes, but at least makes me feel I am doing something real and new.

Wednesday, 9 May 2012

The Metal Box Problem.


In spring last year (6th April) I was asked to visit St Andrew's Physics and Astronomy Department to talk about MiHsC. Well, the reality is I managed to get myself invited because I had met one of them, Dr HongSheng Zhao, at an Alternative Gravities conference in 2006.

Prof Keith Horne kindly organised my visit, and it was a fruitful in some ways, although nothing came of it regarding collaboration. At lunch, before I was to give my talk, one incisive chap, whose name I forget, rattled me by asking me whether the Unruh waves I use to generate inertia could penetrate a metal box (Faraday box). This is something I thought about years ago and I eventually decided that MiHsC-inertia would be unaffected by a metal box, since the Unruh waves for the accelerations we see on Earth are 10^16 metres long and should be able to penetrate (submarines can pick up very long EM waves deep under the conducting sea). The consensus round the table was that the EM component that I was focusing on could not penetrate, but other components of the Unruh radiation could.

Later at coffee, one chap (C.Hooley) suggested that what might be possible is that the sub-selection of Unruh waves by the Hubble scale Casimir effect, that I use in MiHsC, might be already tuned into the local space (like a curvature?) and so wouldn't have to get into the metal box and this would also solve the communication with the cosmic boundary problem. I also wonder if the waves might actually get in through the time dimension rather than the spatial (the same thing?). If only I had access to these kind of stimulating conversations every day! Anyway, disregarding for the moment how nature actually does it, the Hubble scale Casimir effect does seem to work for the specific experiments I've looked at so far. Keith asked whether I'd tried to get gravity from MiHsC too, using a sheltering method. I have now tried this and it produced the wrong kind of dependences, but another method is proving more successful..

When I left Keith said that I'd 'Provided some entertainment and given them something to think about'. I wish I had more opportunity to interact with other physicists. I value tricky questions: in my experience progress comes after crises of doubt.

Tuesday, 1 May 2012

Criticism of the thermal model of the Pioneer anomaly


I have just read through the papers by Turyshev et al. (arxiv: 1204.2507, 1107.2886) in which they argue that the Pioneer anomaly is due to thermal radiation from the RTGs bouncing anisotropically off the spacecraft antenna. First of all, well done to them and the Planetary society for the Pioneer data rescue: the data is the important thing, and I appreciate a lot of work has gone into the finite element modelling. However, I have some criticisms of their thermal explanation of the anomaly:

1) An identical anomaly to the Pioneers' was also found by Anderson et al. in data from the Solar Ulysses probe, and, less conclusively, in Galileo probe data. See: http://arxiv.org/abs/gr-qc/9808081. These spacecraft were very different, and it's unlikely that thermal effects would cause the same acceleration.

2) As they themselves say in their 2011 paper (page 4) the Pioneer data is still too noisy to prove whether there is a decay with time in the anomaly or not, and a thermal explanation can't be supported without a proven decay.

3) The half life of the decay with time that best fits their thermal model is 28.8 or 36.9 years whereas the half life of the Plutonium on board is 87 years.

4) Their predicted anomaly is at its largest in the inner Solar system where there was no Pioneer anomaly. They have got around this by proposing there was an exactly cancelling push because the Sunward side of the craft was warmer due to sunlight (Turyshev kindly emailed me to point this out), but looking at their Fig. 2 from their latter paper this does not exactly cancel the onboard thermal effects, so I guess they had to adjust the momentum flux from photons close to the Sun that was originally assumed by Anderson et al.?

5) Anderson et al. (2002) (arXiv:gr-qc/0104064, p32-33) said that, since most of the heat from the RTGs was radiated from fins whose flat surfaces were not pointing at the antenna, only their narrow edges, only 4W of power, could have hit the antenna, leading to a maximum acceleration of only 0.55*10^-10 m/s^2.

6) Since the power radiation Q is proportional to the fourth power of temperature, I'd like to see the temperature errors they get, since any errors from this source would be hugely magnified.

More generally, I always find it difficult to accept a paper when a very complex and unrevealed process (over 3000 finite elements, not fully detailed in the paper) and with fitting parameters, is used to get to a previously known answer, and no experiment is suggested that might unambiguously test it against rivals. I dislike dark matter for similar reasons. I'd like to see them present a simplified order-of-magnitude calculation so others can reproduce what they have done on paper.

Here's my explanation for the Pioneer anomaly using MiHsC, published in MNRAS: preprint.

Monday, 23 April 2012

Breakfast at the 100 Year Starship

I went to the 100 Year Starship Symposium in Orlando, Florida, last year and presented some of my work on "Quantised Inertia and FTL". After my talk, this chap, a fellow presenter, Jack Sarfatti, stood up and said: "I'm very excited by your work, and it might even be true! However, what you need to ask is WHEN is your event horizon" (ie: the boundary I use for the Hubble-scale Casimir effect).

The next morning at breakfast a friendly chap from New York came and sat with me and said, in the nicest way possible, that my talk had reminded him why he'd left physics for the law. Anyway, I went to get my scrabbled eggs, plus watermelon on the side, and I saw Jack Sarfatti sitting alone at a table and said "Hello". He exploded out of his seat, and joined me and the lawyer. He quickly explained the holographic principle, how it explains why entropy increases, and again why he thinks I need to ask the question: "WHEN is my event horizon?". After 10 minutes of intensity my excluded lawyer friend stood up to go, and said to me: "It was nice meeting you" and then said to Jack: "Well, I didn't meet you, but it was very educational!". Jack didn't seem to notice this and carried on. I liked Jack immediately. Reading about him later, it seems he's dabbled into just about everything, but that's fine by me: to get good ideas you need lots of different ones, some crazy, so long as you do then test them properly. I do think it would be hard, in a conversation, to get him to listen for any length of time though.

I appreciated Jack's comment about causality. I have wondered for over 20 years how to make time flexible. I tried to write a paper (my first) back in 1992 suggesting a theory of fuzzy time, and someone from the physics department I'd just graduated from said: "Too woolly, you need to suggest a test, and also it sounds like Cramer". I learned then that John Cramer had suggested a transactional (noncausal) interpretation of quantum mechanics. Bizzarely, 20 years later it was him chairing our exotic session at the 100 Year Starship Symposium. Anyway, after over 20 years in physics I have learned to look for tests, so, for causality, where's the data to show the way?

Well, John Cramer is setting up a test for retrocausality, see: http://faculty.washington.edu/jcramer/

Thursday, 12 April 2012

An analogy for MiHsC


The following is one of my attempts at a rough analogy for MiHsC. Imagine an ant who has somehow strayed onto a drum. Everytime the poor ant tries to move, he makes waves on the drumskin that bounce him and slow him down (a sort of inertia). Now, only waves of certain wavelengths can exist on drumskins (and in harbours too) those with nodes (non moving parts) at the solid boundary or edge. The allowed waves are: ones with a wavelength twice the drum's diameter, the same size as the diameter, 2/3 times the diameter, 1/2 the diameter and so on.. If the ant knew this then maybe he could move in such a way that the waves he excites are too long, or the wrong wavelength, to fit onto the drumskin (are disallowed), then he could move without being bounced around (less inertial mass), and get back home quicker.

There's a saying: "More haste, less speed". In this case maybe "Less haste, more speed" would be more apt. MiHsC is similar, but replace the ant with any object, the drumskin waves with Unruh waves and the drumskin with the Hubble volume. To lose inertial mass, accelerate more slowly. The cosmos is a drum? - Feynman would have been chuffed.

Tuesday, 3 April 2012

At the NAM in Manchester

Last Thursday I attended one day of the UK-Germany National Astronomy Meeting in Manchester and I gave a talk in the (unofficial) Cosmology 4 'Dark Energy, Dark Matter and Modified Gravity' session on my recent work 'Testing quantised inertia with wide binaries'. I was asked a few interesting questions. Someone asked me whether I'd applied MiHsC/QI to the Cosmic Microwave Background (CMB). I have done some work on this: I can model the apparent supression of power at the largest scales using the Hubble-scale Casimir effect, but haven't taken account of curved space yet, and further: that CMB anomaly does not poke outside the error bars yet.

One chap suggested that I could look at photons since they traverse areas of low acceleration. OK, but looking for a more direct test, I am now trying to focus on either very simple astronomical tests (wide binaries) or terrestrial experiments (lab tests). He also said that I should not cite the Pioneer anomaly as a successful test any more because Turyshev et al. have modelled the Pioneer anomaly as a mundane thermal radiative reaction force: heat emitted from the RTGs bounces off and pushes the craft. However, although I haven't yet read their paper in detail, it seems they have used a complex reflection model with many adjustable parameters (tricky) and also I would have expected there to be a significant decay in the Pioneer anomaly if radiation was the cause since the RTGs should have significantly cooled over the 30 years of data, but Anderson et al. saw no decay in the anomaly. Turyshev et al. claim there is a decay. I need to look at the data to decide this.

Anyway, someone then asked 'Can you tell me anything that would convince me that inertia is caused by Unruh radiation'. That nonplussed me because I'd just presented all my comparisons of MiHsC/QI with the data and the agreement with data is what convinces me. Anyway, I answered: 'My main reason is that it works'. By this I mean that if you do assume that inertia comes from Unruh radiation, and the Hubble-scale Casimir effect which follows, then you get successful experimental predictions that are unobtainable from other theories. I do not yet have a specific physical model for exactly how the Unruh radiation might interact with objects and cause inertia (I think this is what this person wanted, but for me that has to come later, and slowly). I have a few ideas about possible mechanisms, but no experiments to discriminate between them yet.

Tuesday, 20 March 2012

Sheldon's nightmare scenario.

Speaking of inertia: it affects subjects too. I'm sure it would horrify the character of Sheldon on The Big Bang Theory, but most of standard physics has been developed over the past three hundred years by people familiar mostly with the working of human-made machines. The implication is that theory reflects technology. This has led to a physics that predicts simple things well in the short term, but restricts us to the view that the machine-universe is running down to its inevitable heat death. I like to think instead that the universe is growing, in a way more akin to organisms or the www, and that now we are starting to understand biology and computing, which require us to use the idea of information, physics will have to be overhauled to take this view. Of course, this may be all new-age hot air, unless an experiment can be suggested that can discriminate between this new 'informatics' and the old physics.

I have lots of fun imagining Sheldon & Wolowitz from the Big Bang Theory (modern versions of Plato and Aristotle) discussing this idea. For example, how's this?:

Wolo: So...Sheldon. How about this idea that theoretical physicists get their paradigms from engineers?
Shel: Hokum, and I have some empirical data to disprove it.
Wolo: OK, bring it on!
Shel: Do I ever listen to you?
Wolo: Granted, but you can't base your argument on one data point.
Shel: Howard, I'm a theoretical physicist. I don't even need one data point!
Wolo: This is nonsense. Even you can't ignore objective reality!
Shel: Alright (sigh), if you insist on dragging mundane reality into it, then you know me to be a subscriber to the many-worlds interpretation of quantum mechanics.
Wolo: So?
Shel: I can assure you, that in none of those many worlds do any Sheldon's listen to you... That's an infinite number of data points right there!
Wolo: Note to self: don't argue with crazy people.

Friday, 2 March 2012

Zen and the Art of Physics?

Last night I dived back into an old favourite: R.M. Pirsig's Zen and the Art of Motorcycle Maintainance, and found an anecdote that summarises a point I've been longing to make: why naive observation is a good thing. Here it is: a teacher asks his students to write an original essay about their home town. One student finds that she cannot write anything original about this abstract concept, so the teacher tells her to focus on an actual house in the town. She notices an interesting brick and is immediately able to say original things about this brick and work outwards from there.

I like this vignette because it illustrates a problem I have with the tendency in modern physics, art and other subjects, to model things that cannot be directly observed or tested. For example, abstract art, or, in physics: the big bang. For me, studies of the big bang represent humans hubristically trying to impose whatever is going on inside their heads (standard physics) on the universe, rather than humbly allowing the universe to change what is going on in their heads (ie: by learning). The solution is to allow reality to inspire new ideas, most efficiently by looking for observational anomalies closer to home (interesting bricks) without presupposing any theory.

Wednesday, 29 February 2012

Experiments and logic

At the moment the OPERA faster than light (FTL) result is far too uncertain to be trusted, and needs replication, but, in an article just published in New Scientist [1] (see below) R. Garisto argues that: "models which explain [the FTL] by breaking relativity are ruled out". He says he knows this because a recent paper by Cohen and Glashow [2] proposed that a neutrino going faster than light "may lose energy rapidly by bremsstrahlung", and the OPERA neutrinos did not, so they cannot have travelled FTL. Surely there is an error in logic here, since Garisto is effectively saying: you cannot violate standard physics unless you do it using standard physics.

Travelling faster than light violates standard physics in about the biggest way possible, and it is wrong to reject theories that explain experimental results (as Garisto says he has) by saying that they violate standard physics. Such an attitude would doom fundamental physics to an endless sterility. In physics, experiment (even if later shown to be flawed) must come first. If the OPERA result is supported experimentally, then standard physics is going to have to mumble sheepish apologies, and new physics will be needed. My point here is not that I think the OPERA result is necessarily correct, but rather that, in cases like this, objective logic should be applied, rather than a blind faith in standard physics.

[1] http://www.newscientist.com/article/dn21515-lights-speed-limit-is-safe-for-now.html
[2] http://prl.aps.org/abstract/PRL/v107/i18/e181803

Saturday, 18 February 2012

Underlying randomness

One of the courses I teach is climatology, and I try to emphasise both the observations and the maths and theory. In climatology there are a lot of simple balances. For example (to simplify): in the north Atlantic the wind pushes the water up into a wide bump centred on the Azores and the ocean currents flow clockwise around this bump producing Coriolis forces inwards that balance the pressure-gradient forces outwards. This produces a simple circular pattern (in geostrophic balance). I think this illustrates an interesting point: systems, like the ocean, jiggle around randomly, until one day, by chance, they find a balance, and it is the nature of balances, once set up, to remain, since they are stable. By the time we get around to observing it, and for most of the time, this simple balance is what we see. I guess this also applies to the rest of physics and is behind the simplicity and predictability of what we see in the world, but the crazy underlying randomness is always there, ready to return.

Friday, 3 February 2012

Wide binaries

There has been a great observational study done recently by Hernandez et al. (see: http://arxiv.org/abs/1105.1873). They have looked at wide binary stars and found that when they are separated by 7000AU or more, so that their accelerations decrease below 2*10^-10 m/s^2, then their behaviour becomes non-Newtonian, in that their orbital speeds are so large that the centrifugal (inertial) forces separating them should be greater than the gravitational pull inwards from the mass that we can see, so they should zoom off to infinity. A similar behaviour is seen in galaxy rotation curves, which deviate from Newtonian behaviour below this same acceleration. For these simple binary systems, it is hard to see how dark matter (DM) could kick in at a particular acceleration, and Newton and MoND both predict only about 1/10th of the orbital speeds seen. This provides a experimentum crucis, and so I have recently been testing MiHsC on these data: because of their low acceleration, MiHsC predicts a decrease in the stars’ inertial masses so they manage to orbit each other at the faster speed without inertia separating them. The orbital speed predicted by MiHsC is still only 1/2 of that seen, but this is much better than the 1/10th from Newtonian dynamics and MoND. I have just today submitted an abstract on this to the UK’s National Astronomy Meeting (NAM 2012).