Obviously someone else has already noticed the remarkable similarity between the structure of the human brain and that revealed by computer simulations of the large-scale structure of the Universe.
Does this mean that dark matter is really just all in the mind?
Amidst the doom and gloom of spending cuts and Ministerial incompetence we’re sometimes liable to forget what it’s all about. Last night provided us with a reminder, in the form of the Astronomy Photographer of the Year competition held at the National Maritime Museum (site of the Royal Observatory at Greenwich). There’s a varied selection of gorgeous entries on today’s Guardian, but this stunning image by Tom Lowe was the overall winner. Congratulations to him!
I don’t know why, but last week was my most popular week ever, at least in terms of blog hits! I was going to follow up with a foray into the role of spin in quantum mechanics, but decided instead to settle for a less ambitious project for this evening.
Yesterday I walked past the cricket ground at the SWALEC Stadium in Sophia Gardens, Cardiff, during the Twenty20 international between England and Pakistan. There is another match of this type tomorrow night which I’ll actually be going to, as long as it’s not rained off, but I have too many things to do to go to both games. Anyway, England’s excellent off-spinner Graham Swann was bowling when I watched through a gap in the stands at the river end of the stadium. He seemed to be getting an impressive amount of turn, and I got wondering about how fast a bowler like “Swannee” actual spins the ball.
For those of you not so familiar with cricket here’s a clip of another prodigious spinner of the ball, Australia’s legend of legspin Shane Warne:
For beginners, the game of cricket is a bit similar to baseball (insofar as it’s a game involving a bat and a ball), but the “strike zone” in cricket is a physical object ( a “wicket” made of wooden stumps with bails balanced on the top) unlike the baseball equivalent, which exists only in the mind of the umpire. The batsman must prevent the ball hitting the wicket and also try to score runs if he can. In contrast to baseball, however, he doesn’t have to score; he can elect to play a purely defensive shot or even not play any short at all if he judges the ball is going to miss, which is what happened to the hapless batsman in the clip.
You will see that Warne imparts considerable spin on the ball, which has the effect of making it change direction when it bounces. The fact that the ball hits the playing surface before the batsman has a chance to play it introduces extra variables that you don’t see in baseball, such as the state of the pitch (which generally deteriorates over the five days of a Test match, especially in the “rough” where bowlers have been running in). A spin bowler who causes the ball to deviate from right to left is called a legspin bowler, while one who makes it turn the other way is an offspin bowler. An orthodox legspinner generates most of the spin from a flick of the wrist while an offspinner mainly lets his fingers do the torquing.
Another difference that’s worth mentioning with respect to baseball is that the ball is bowled, i.e. the bowler’s arm is not supposed to bend during the delivery (although apparently that doesn’t apply if he’s from Sri Lanka). However, the bowler is allowed to take a run up, which will be quite short for a spin bowler, but long like a javelin thrower if it’s a fast bowler. Fast bowlers – who can bowl up to 95 mph (150 km/h) – don’t spin the ball to any degree but have other tricks up their sleeve I haven’t got time to go into here. A typical spin bowler delivers the ball at speeds ranging from 45 mph to 60 mph (70 km/hour to 100 km/hour).
The physical properties of a cricket ball are specified in the Laws of Cricket. It must be between 22.4 and 22.9 cm in circumference, i.e. 3.57 to 3.64 cm in radius and must weigh between 155.9g and 163g. It’s round, made of cork, and surrounded by a leather case with a stitched seam.
So now, after all that, I can give a back-of-the-envelope answer to the question I was wondering about on the way home. Looking at the video clip my initial impression was that the ball is deflected by an angle as large as a radian, but in fact the foreshortening effect of the camera is quite deceptive. In fact the ball deviates by less than a metre between pitching and hitting the stumps. There is a gap of about 1 metre between the popping crease (where the batsman stands) and the stumps – it looks much less from the camera angle shown – and the ball probably pitches at least 2 metres in front of the crease. I would guess therefore that it actually deflects by an angle less than twenty degrees or so.
What happens physically is that some of the rotational kinetic energy of the ball is converted into translational kinetic energy associated with a component of the velocity at right angles to the original direction of travel. In order for the deflection to be so large, the available rotational kinetic energy must be non-negligible compared to the original kinetic energy of the ball. Suppose the mass of the ball is 
Approximating the ball as a uniform sphere of mass 
or 
This estimate is obviously very rough because it ignores the direction of spin and the efficiency with the ball grips on the pitch – friction is obviously involved in the change of direction – but it gives a reasonable ballpark (or at least cricketground) estimate.
Of course if the bowler does the same thing every time it’s relatively easy for the batsman to allow for the spin. The best bowlers therefore vary the amount and angle of spin they impart on each ball. Most, in fact, have at least two qualitatively different types of ball but they disguise the differences in the act of delivery. Offspinners typically have an “arm ball” which doesn’t really spin but holds its line without appearing to be any different to their spinning delivery. Legspinners usually have a variety of alternative balls, including a topspinner and/or a flipper and/or a googly. The latter is a ball that comes out of the back of the hand and actually spins the opposite way to a legspinner while being produced with apparently the same action. It’s very hard to bowl a googly accurately, but it’s a deadly thing when done right.
Another thing also worth mentioning is that the rotation of the cricket ball also causes a deviation of its flightpath through the air, by virtue of the Magnus effect. This causes the ball to curve in the air in the opposite direction to which it is going to deviate on bouncing, i.e. it would drift into a right-handed batsman before breaking away from him off the pitch. You can see a considerable amount of such movement in the video clip, away from the left-hander in the air and then back into him off the pitch. Nature clearly likes to make things tough for batsmen!
With a number of secret weapons in his armoury the spin bowler can be a formidable opponent, a fact that has apparently been known to poets, philosophers and astronomers for the best part of a thousand years:
The Ball no Question makes of Ayes and Noes,
But Right or Left, as strikes the Player goes;
And he that toss’d Thee down into the Field,
He knows about it all — He knows — HE knows!
The Rubaiyat of Omar Khayyam [50]
The blogosphere, even the tiny little bit of it that I know anything about, has a habit of summoning up strange coincidences between things so, following EM Forster’s maxim “only connect”, I thought I’d spend a lazy saturday lunchtime trying to draw a couple of them together.
A few days ago I posted what was intended to be a fun little item about the wave-particle duality in quantum mechanics. Basically, what I was trying to say is that there’s no real problem about thinking of an electron as behaving sometimes like a wave and sometimes like a particle because, in reality (whatever that is), it is neither. “Particle” and “wave” are useful abstractions but they are not in an exact one-to-one correspondence with natural phenomena.
Before going on I should point out that the vast majority of physicists are well away of the distinction between, say, the “theoretical” electron and whatever the “real thing” is. We physicists tend to live in theory space rather than in the real world, so we tend to teach physics by developing the formal mathematical properties of the “electron” (or “electric field”) or whatever, and working out what experimental consequences these entail in certain situations. Generally speaking, the theory works so well in practice that we often talk about the theoretical electron that exists in the realm of mathematics and the electron-in-itself as if they are one and the same thing. As long as this is just a pragmatic shorthand, it’s fine. However, I think we need to be careful to keep this sort of language under control. Pushing theoretical ideas out into the ontological domain is a dangerous game. Physics – especially quantum physics – is best understood as a branch of epistemology. What is known? is safer ground than what is there?
Anyway, my little piece sparked a number of interesting comments on Reddit, including a thread that went along the lines “of course an electron is neither a particle nor a wave, it’s actually a spin-1/2 projective representation of the Lorentz Group on a Hilbert space”. That description, involving more sophisticated mathematical concepts than those involved in bog-standard quantum mechanics, undoubtedly provides a more complete account of natural phenomena associated with the electrons and electrical fields, but I’ll stick to my guns and maintain that it still introduces a deep confusion to assert that the electron “is” something mathematical, whether that’s a “spin-1/2 projective representation” or a complex function or anything else. That’s saying something physical is a mathematical. Both entities have some sort of existence, of course, but not the same sort, and the one cannot “be” the other. “Certain aspects of an electron’s behaviour can be described by certain mathematical structures” is as I’m prepared to go.
Pushing deeper than quantum mechanics, into the realm of quantum field theory, there was the following contribution:
The electron field is a quantum field as described in quantum field theories. A quantum field covers all space time and in each point the quantum field is in some state, it could be the ground state or it could be an excitation above the ground state. The excitations of the electron field are the so-called electrons. The mathematical object that describes the electron field possesses, amongst others, certain properties that deal with transformations of the space-time coordinates. If, when performing a transformation of the space-time coordinates, the mathematical object changes in such a way that is compatible with the physics of the quantum field, then one says that the mathematical object of the field (also called field) is represented by a spin 1/2 (in the electron case) representation of a certain group of transformations (the Poincaré group, in this example).I understand your quibbling, it seems natural to think that “spin 1/2″ is a property of the mathematical tool to describe something, not the something itself. If you press on with that distinction however, you should be utterly puzzled of why physics should follow, step by step, the path led by mathematics.
For example, one speaks about the ¨invariance under the local action of the group SU(3)” as a fundamental property of the fields that feel the nuclear strong force. This has two implications, the mathematical object that represents quarks must have 3 ¨strong¨ degrees of freedom (the so-called color) and there must be 32-1 = 8 carriers of the force (the gluons) because the group of transformations in a SU(N) group has N2-1 generators. And this is precisely what is observed.
So an extremely abstract mathematical principle correctly accounts for the dynamics of an inmensely large quantity of phenomena. Why does then physics follow the derivations of mathematics if its true nature is somewhat different?
No doubt this line of reasoning is why so many theoretical physicists seem to adopt a view of the world that regards mathematical theories as being, as it were, “built into” nature rather than being things we humans invented to describe nature. This is a form of Platonic realism.
I’m no expert on matters philosophical, but I’d say that I find this stance very difficult to understand, although I am prepared to go part of the way. I used to work in a Mathematics department many years ago and one of the questions that came up at coffee time occasionally was “Is mathematics invented or discovered?”. In my experience, pure mathematicians always answered “discovered” while others (especially astronomers, said “invented”). For what it’s worth, I think mathematics is a bit of both. Of course we can invent mathematical objects, endow them with certain attributes and proscribe rules for manipulating them and combining them with other entities. However, once invented anything that is worked out from them is “discovered”. In fact, one could argue that all mathematical theorems etc arising within such a system are simply tautological expressions of the rules you started with.
Of course physicists use mathematics to construct models that describe natural phenomena. Here the process is different from mathematical discovery as what we’re trying to do is work out which, if any, of the possible theories is actually the one that accounts best for whatever empirical data we have. While it’s true that this programme requires us to accept that there are natural phenomena that can be described in mathematical terms, I do not accept that it requires us to accept that nature “is” mathematical. It requires that there be some sort of law governing some of aspects of nature’s behaviour but not that such laws account for everything.
Of course, mathematical ideas have been extremely successful in helping physicists build new physical descriptions of reality. On the other hand, however, there is a great deal of mathematical formalism that is is not useful in this way. Physicists have had to select those mathematical object that we can use to represent natural phenomena, like selecting words from a dictionary. The fact that we can assemble a sentence using words from the Oxford English Dictionary that conveys some information about something we see doesn’t not mean that what we see “is” English. A whole load of grammatically correct sentences can be constructed that don’t make any sense in terms of observable reality, just as there is a great deal of mathematics that is internally self-consistent but makes no contact with physics.
Moreover, to the person whose quote I commented on above, I’d agree that the properties of the SU(3) gauge group have indeed accounted for many phenomena associated with the strong interaction, which is why the standard model of particle physics contains 8 gluons and quarks carrying a three-fold colour charge as described by quantum chromodynamics. Leaving aside the fact that QCD is such a terribly difficult theory to work with – in practice it involves nightmarish lattice calculations on a scale to make even the most diehard enthusiast cringe – what I would ask is whether this description in any case sufficient for us to assert that it describes “true nature”? Many physicists will no doubt disagree with me, but I don’t think so. It’s a map, not the territory.
So why am I boring you all with this rambling dissertation? Well, it brings me to my other post – about Stephen Hawking’s comments about God. I don’t want to go over that issue again – frankly, I was bored with it before I’d finished writing my own blog post – but it does relate to the bee that I often find in my bonnet about the tendency of many modern theoretical physicists to assign the wrong category of existence to their mathematical ideas. The prime example that springs to my mind is the multiverse. I can tolerate certain versions of the multiverse idea, in fact. What I can’t swallow, however is the identification of the possible landscape of string theory vacua – essentially a huge set of possible solutions of a complicated set of mathematical equations – with a realised set of “parallel universes”. That particular ontological step just seems absurd to me.
I’m just about done, but one more thing I’d say to finish with is concerns the (admittedly overused) metaphor of maps and territories. Maps are undoubtedly useful in helping us find our way around, but we have to remember that there are always things that aren’t on the map at all. If we rely too heavily on one, we might miss something of great interest that the cartographer didn’t think important. Likewise if we fool ourselves into thinking our descriptions of nature are so complete that they “are” all that nature is, then we might miss the road to a better understanding.
I woke up this morning to the news that, according to Stephen Hawking, God did not create the Universe but it was instead an “inevitable consequence of the Law of Physics”. By sheer coincidence this daft pronouncement has come out at the same time as the publication of Professor Hawking’s new book, an extract of which appears in todays Times.
It’s interesting that such a fatuous statement managed to become a lead item on the radio news and a headline in all the national newspapers despite being so obviously devoid of any meaning whatsoever. How can the Universe be “a consequence” of the theories that we invented to describe it? To me that’s just like saying that the Lake District is a consequence of an Ordnance Survey map. And where did the Laws of Physics come from, if not from God?
Stephen Hawking is undoubtedly a very brilliant theoretical physicist. However, something I’ve noticed about theoretical physicists over the years is that if you get them talking on subjects outside physics they are generally likely to say things just as daft as some drunk bloke down the pub. I’m afraid this is a case in point.
Part of me just wants to laugh this story off, but another part is alarmed at what must appear to many to be an example of an arrogant scientist presuming to pass judgement on subjects that are really none of his business. When scientists complain about the lack of enthusiasm shown by sections of the public towards their subject, perhaps they should take seriously the alienating effect that such statements can have. This kind of thing isn’t what I’d call public engagement. Quite the opposite, in fact.
In case anyone is interested, I am not religious but I do think that there are many things that science does not – and probably will never – explain, such as why there is something rather than nothing. I also believe that science and religious belief are not in principle incompatible – although whether there is a conflict in practice does depend of course on the form of religious belief and how it is observed. God and physics are in my view pretty much orthogonal. To put it another way, if I were religious, there’s nothing in theoretical physics that would change make me want to change my mind. However, I’ll leave it to those many physicists who are learned in matters of theology to take up the (metaphorical) cudgels with Professor Hawking.
No doubt this bit of publicity will increase the sales of the new book, so I’ve decided to point out that I have written a book myself on precisely this question, which is available from all good airports bookshops. I’m sure you’ll understand that there isn’t a hint of opportunism in the way I’m drawing this to your attention. If you think this is a cynical attempt to cash in then all I can say is
I also noticed that today’s Grauniad is offering a poll on the existence or non-existence of God. I noticed some time ago that there’s a poll facility on WordPress, so this gives me an excuse to try repeating it here. Anything dumb the Guardian can do, I can do dumber. However, owing to funding cuts I’ve decided to do a single poll encompassing several topical news stories at the same time.
When I was an undergraduate I was often told by lecturers that I should find quantum mechanics very difficult, because it is unlike the classical physics I had learned about up to that point. The difference – or so I was informed – was that classical systems were predictable, but quantum systems were not. For that reason the microscopic world could only be described in terms of probabilities. I was a bit confused by this, because I already knew that many classical systems were predictable in principle, but not really in practice. I blogged about this some time ago, in fact. It was only when I had studied theory for a long time – almost three years – that I realised what was the correct way to be confused about it. In short, quantum probability is a very strange kind of probability that displays many peculiarities and subtleties that one doesn’t see in the kind of systems we normally think of as “random”, such as coin-tossing or roulette wheels.
To illustrate how curious the quantum universe is we have to look no further than the very basic level of quantum theory, as formulated by the founder of wave mechanics, Erwin Schrödinger. Schrödinger was born in 1887 into an affluent Austrian family made rich by a successful oilcloth business run by his father. He was educated at home by a private tutor before going to the University of Vienna where he obtained his doctorate in 1910. During the First World War he served in the artillery, but was posted to an isolated fort where he found lots of time to read about physics. After the end of hostilities he travelled around Europe and started a series of inspired papers on the subject now known as wave mechanics; his first work on this topic appeared in 1926. He succeeded Planck as Professor of Theoretical Physics in Berlin, but left for Oxford when Hitler took control of Germany in 1933. He left Oxford in 1936 to return to Austria but fled when the Nazis seized the country and he ended up in Dublin, at the Institute for Advanced Studies which was created especially for him by the Irish Taoiseach, Eamon de Valera. He remained there happily for 17 years before returning to his native land at the University of Vienna. Sadly, he became ill shortly after arriving there and died in 1961.
Schrödinger was a friendly and informal man who got on extremely well with colleagues and students alike. He was also a bit scruffy even to the extent that he sometimes had trouble getting into major scientific conferences, such as the Solvay conferences which are exclusively arranged for winners of the Nobel Prize. Physicists have never been noted for their sartorial elegance, but Schrödinger must have been an extreme case.
The theory of wave mechanics arose from work published in 1924 by de Broglie who had suggested that every particle has a wave somehow associated with it, and the overall behaviour of a system resulted from some combination of its particle-like and wave-like properties. What Schrödinger did was to write down an equation, involving a Hamiltonian describing particle motion of the form I have discussed before, but written in such a way as to resemble the equation used to describe wave phenomena throughout physics. The resulting mathematical form for a single particle is
in which the term 
At the time Schrödinger was developing his theory of wave mechanics it had a rival, called matrix mechanics, developed by Werner Heisenberg and others. Paul Dirac later proved that wave mechanics and matrix mechanics were mathematically equivalent; these days physicists generally use whichever of these two approaches is most convenient for particular problems.
Schrödinger’s equation is important historically because it brought together lots of bits and pieces of ideas connected with quantum theory into a single coherent descriptive framework. For example, in 1911 Niels Bohr had begun looking at a simple theory for the hydrogen atom which involved a nucleus consisting of a positively charged proton with a negatively charged electron moving around it in a circular orbit. According to standard electromagnetic theory this picture has a flaw in it: the electron is accelerating and consequently should radiate energy. The orbit of the electron should therefore decay rather quickly.
Bohr hypothesized that special states of this system were actually stable; these states were ones in which the orbital angular momentum of the electron was an integer multiple of Planck’s constant. This simple idea endows the hydrogen atom with a discrete set of energy levels which, as Bohr showed in 1913, were consistent with the appearance of sharp lines in the spectrum of light emitted by hydrogen gas when it is excited by, for example, an electrical discharge. The calculated positions of these lines were in good agreement with measurements made by Rydberg so the Bohr theory was in good shape. But where did the quantised angular momentum come from?
The Schrödinger equation describes some form of wave; its solutions 
The Schrödinger equation can be applied successfully to systems which are much more complicated than the hydrogen atom, such as complex atoms with many electrons orbiting the nucleus and interacting with each other. In this context, this description is the basis of most work in theoretical chemistry. But it also poses very deep conceptual challenges, chiefly about how the notion of a “particle” relates to the “wave” that somehow accompanies it.
To illustrate the riddle, consider a very simple experiment where particles of some type (say electrons, but it doesn’t really matter; similar experiments can be done with photons or other particles) emerge from the source on the left, pass through the slits in the middle and are detected in the screen at the right.
In a purely “particle” description we would think of the electrons as little billiard balls being fired from the source. Each one then travels along a well-defined path, somehow interacts with the screen and ends up in some position on the detector. On the other hand, in a “wave” description we would imagine a wave front emerging from the source, being diffracted by the screen and ending up as some kind of interference pattern at the detector. This is what we see with light, for example, in the phenomenon known as Young’s fringes.
In quantum theory we have to think of the system as being in some sense both a wave and a particle. This is forced on us by the fact that we actually observe a pattern of “fringes” at the detector, indicating wave-like interference, but we also can detect the arrival of individual electrons as little dots. Somehow the propensity of electrons to arrive in positions on the screen is controlled by an element of waviness, but they manage to retain some aspect of their particleness. Moreover, one can turn the source intensity down to a level where there is only every one electron in the experiment at any time. One sees the dots arrive one by one on the detector, but adding them up over a long time still yields a pattern of fringes.
Curiouser and curiouser, said Alice.
Eventually the community of physicists settled on a party line that most still stick to: that the wave-function controls the probability of finding an electron at some position when a measurement is made. In fact the mathematical description of wave phenomena favoured by physicists involves complex numbers, so at each point in space at time 
I’m not going to into the various philosophical arguments about the interpretation of quantum probabilities here, but I will pass on an analogy that helped me come to grips with the idea that an electron can behave in some respects like a wave and in others like a particle. At first thought, this seems a troubling paradox but it only appears so if you insist that our theoretical ideas are literal representations of what happens in reality. I think it’s much more sensible to treat the mathematics as a kind of map or sketch that is useful for us to do find our way around nature rather than confusing it with nature itself. Neither particles nor waves really exist in the quantum world – they’re just abstractions we use to try to describe as much as we can of what is going on. The fact that it doesn’t work perfectly shouldn’t surprise us, as there are are undoubtedly more things in Heaven and Earth than are dreamt of in our philosophy.
Imagine a mediaeval traveller, the first from your town to go to Africa. On his journeys he sees a rhinoceros, a bizarre creature that is unlike anything he’s ever seen before. Later on, when he gets back, he tries to describe the animal to those at home who haven’t seen it. He thinks very hard. Well, he says, it’s got a long horn on its head, like a unicorn, and it’s got thick leathery skin, like a dragon. Neither dragons nor unicorns exist in nature, but they’re abstractions that are quite useful in conveying something about what a rhinoceros is like.
It’s the same with electrons. Except they don’t have horns and leathery skin. Obviously.
It’s pouring with rain so, rather than set off home and get drenched, I thought I’d spend a few minutes on the blog and hope that the deluge dies down before I leave. Knowing my luck it will probably get worse.
Anyway, I thought I’d put together a short item on the theme of sketching. This is quite a strange subject for me to pick because drawing is something I’m completely useless at, but I hope you’ll bear with me and hopefully it will make some sense in the end.
What spurred me on to think about it was the exhibit I’ve been involved with for the forthcoming Architecture Biennale in Venice as part of a project called Beyond Entropy organized by the Architectural Association School of Architecture. Unfortunately, although I’d originally planned to attend I can’t be there for the opening Symposium, but I hope it turns out to be as successful event as it promises to be!
Anyway, in the course of this project I came across this image of the Moon as drawn by Galileo
This led to an interesting discussion about the role of drawings like this in science. Of course the use of sketches for the scientific representation of images has been superseded by photographic techniques, initially using film and more recently by digital techniques. The advantage of these methods is that they are quicker and also more “objective”. However, there are still many amateur astronomers who make drawings of the Moon as well as objects such as Jupiter and Saturn (which Galileo also drew). Moreover there are other fields in which experienced practioners continue to use pencil drawings in preference to photographic techniques. Archaeology provides many good examples, e.g.
The reason sketching still has a role in such fields is not that it can compete with photography for accuracy or objectivity but that there’s something about the process of sketching that engages the sketcher’s brain in a way that’s very different from taking a photograph. The connection between eye, brain and hand seems to involve a cognitive element that is extremely useful in interpreting notes at a later date. In fact it’s probably their very subjectivity that makes them useful. A thicker stroke of the pencil, or deliberately enhanced shading, or leaving out seemingly irrelevant detail, can help pick out features that seem to the observer to be of particular significance. Months later when you’re trying to write up what you saw from your notes, those deliberate interventions against objectivity will take you back to what you saw with your mind, not just with your eyes.
It doesn’t even matter whether or not you can draw well. The point isn’t so much to explain to other people what you’ve seen, but to record your own interaction with the object you’ve sketched in a way that allows you to preserve something more than a surface recollection.
You might think this is an unscientific thing to do, but I don’t think it is. The scientific process involves an interplay between objective reality and theoretical interpretation and drawing can be a useful part of this discourse. It’s as if the pencil allows the observer to interact with what is observed, forming a closer bond and probably a deeper level of understanding patterns and textures. I’m not saying it replaces a purely passive recording method like photography, but it can definitely help it.
I have not a shred of psychological evidence to back this up, but I’d also assert that sketching is very good for the learning process too. Nowadays we tend to give out handouts of diagrams involved in physics, whether they relate to the design of apparatus or the geometrical configuration of a physical system. There’s a reason for doing this – they take a long time to draw and there’s a likelihood students will make mistakes copying them down. However, I’ve always found that the only way to really take in what a diagram is saying is to try to draw it again myself. Even if the level of draftsmanship is worse, the level of understanding is undoubtedly better.Merely looking at someone else’s representation of something won’t give your brain as a good a feeling for what it is trying to say as you would get if you tried to draw it yourself.
Perhaps what happens is that simply looking at a diagram only involves the connection between eye and brain. Drawing a copy requires also the connection between brain and hand. Maybe this additional connection brings in additional levels of brain functionality. Sketching iinvolves your brain in an interaction that is different from merely looking.
The problem with excessive use of handouts – and this applies not only to figures but also to lecture notes – is that they turn teaching into a very passive process. Taking notes in your own hand, and supplementing them with your own sketches – however scribbly and incomprehensible they may appear to other people – is a much more active way to learn than collecting a stack of printed notes and meticulously accurate diagrams. And if it was good enough for Galileo, it should good enough for most of us!
Now it’s stopped raining so I’m off home!
For tonight’s post I thought I’d compose a commentary on a couple of connected controversies suggested by an interestingly provocative piece by Nigel Hawkes in the Independent this weekend entitled Peer Review journals aren’t worth the paper they’re written on. Here is an excerpt:
The truth is that peer review is largely hokum. What happens if a peer-reviewed journal rejects a paper? It gets sent to another peer-reviewed journal a bit further down the pecking order, which is happy to publish it. Peer review seldom detects fraud, or even mistakes. It is biased against women and against less famous institutions. Its benefits are statistically insignificant and its risks – academic log-rolling, suppression of unfashionable ideas, and the irresistible opportunity to put a spoke in a rival’s wheel – are seldom examined.
In contrast to many of my academic colleagues I largely agree with Nigel Hawkes, but I urge you to read the piece yourself to see whether you are convinced by his argument.
I’m not actually convinced that peer review is as biased as Hawkes asserts. I rather think that the strongest argument against the scientific journal establishment is the ruthless racketeering of the academic publishers that profit from it. Still, I do think he has a point. Scientists who garner esteem and influence in the public domain through their work should be required to defend it our in the open to both scientists and non-scientists alike. I’m not saying that’s easy to do in the face of ill-informed or even illiterate criticism, but it is in my view a necessary price to pay, especially when the research is funded by the taxpayer.
It’s not that I think many scientists are involved in sinister activities, manipulating their data and fiddling their results behind closed doors, but that as long as there is an aura of secrecy it will always fuel the conspiracy theories on which the enemies of reason thrive. We often hear the accusation that scientists behave as if they are priests. I don’t think they do, but there are certainly aspects of scientific practice that make it appear that way, and the closed world of academic publishing is one of the things that desperately needs to be opened up.
For a start, I think we scientists should forget academic journals and peer review, and publish our results directly in open access repositories. In the old days journals were necessary to communicate scientific work. Peer review guaranteed a certain level of quality. But nowadays it is unnecessary. Good work will achieve visibility through the attention others give it. Likewise open scrutiny will be a far more effective way of identifying errors than the existing referee process. Some steps will have to be taken to prevent abuse of the access to databases and even then I suspect a great deal of crank papers will make it through. But in the long run, I strongly believe this is the only way that science can develop in the age of digital democracy.
But scrapping the journals is only part of the story. I’d also argue that all scientists undertaking publically funded research should be required to put their raw data in the public domain too. I would allow a short proprietary period after the experiments, observations or whatever form of data collection is involved. I can also see that ethical issues may require certain data to be witheld, such as the names of subjects in medical trials. Issues will also arise when research is funded commercially rather than by the taxpaper. However, I still maintain that full disclosure of all raw data should be the rule rather than the exception. After all, if it’s research that’s funded by the public, it is really the public that owns the data anyway.
In astronomy this is pretty much the way things operate nowadays, in fact. Maybe stargazers have a more romantic way of thinking about scientific progress than their more earthly counterparts, but it is quite normal – even obligatory for certain publically funded projects – for surveys to release all their data. I used to think that it was enough just to publish the final results, but I’ve become so distrustful of the abuse of statistics throughout the field that I think it is necessary for independent scientists to check every step of the analysis of every major result. In the past it was simply too difficult to publish large catalogues in a form that anyone could use, but nowadays that is simply no longer the case. Astronomers have embraced this reality, and it is liberated them.
To give a good example of the benefits of this approach, take the Wilkinson Microwave Anisotropy Probe (WMAP) which released full data sets after one, three, five and seven years of operation. Scores of groups around the world have done their best to find glitches in the data and errors in the analysis without turning up anything particularly significant. The standing of the WMAP team is all the higher for having done this, although I don’t know whether they would have chosen to had they not been required to do so under the terms of their funding!
In the world of astronomy research it’s not at all unusual to find data for the object or set of objects you’re interested in from a public database, or by politely asking another team if they wouldn’t mind sharing their results. And if you happen to come across a puzzling result you suspect might be erroneous and want to check the calculations, you just ask the author for the numbers and, generally speaking, they send the numbers to you. A disagreement may ensue about who is right and who is wrong, but that’s the way science is supposed to work. Everything must be open to question. It’s often a chaotic process, but it’s a process all the same, and it is one that has servedus incredibly well.
I was quite surprised recently to learn that this isn’t the way other scientific disciplines operate at all. When I challenged the statistical analysis in a paper on neuroscience recently, my request to have a look at the data myself was greeted with a frosty refusal. The authors seemed to take it as a personal affront that anyone might have the nerve to question their study. I had no alternative but to go public with my doubts, and my concerns have never been satisfactorily answered. How many other examples are there wherein application of the scientific method has come to a grinding halt because of compulsive secrecy? Nobody likes to have their failings exposed in public, and I’m sure no scientists likes see an error pointed out, but surely it’s better to be seen to have made an error than to maintain a front that perpetuates the suspicion of malpractice?
Another, more topical, example concerns the University of East Anglia’s Climatic Research Unit which was involved in the Climategate scandal and which has apparently now decided that it wants to share its data. Fine, but I find it absolutely amazing that such centres have been able to get away with being so secretive in the past. Their behaviour was guaranteed to lead to suspicions that they had something to hide. The public debate about climate change may be noisy and generally ill-informed but it’s a debate we must have out in the open.
I’m not going to get all sanctimonious about `pure’ science nor am I going to question the motives of individuals working in disciplines I know very little about. I would, however, say that from the outside it certainly appears that there is often a lot more going on in the world of academic research than the simple quest for knowledge.
Of course there are risks in opening up the operation of science in the way I’m suggesting. Cranks will probably proliferate, but we’ll no doubt get used to them- I’m a cosmologist and I’m pretty much used to them already! Some good work may find it a bit harder to be recognized. Lack of peer review may mean more erroneous results see the light of day. Empire-builders won’t like it much either, as a truly open system of publication will be a great leveller of reputations. But in the final analysis, the risk of sticking to our arcane practices is far higher. Public distrust will grow and centuries of progress may be swept aside on a wave of irrationality. If the price for avoiding that is to change our attitude to who owns our data, then it’s a price well worth paying.
Just a short post to convey the very sad news that the great Italian physicist Nicola Cabibbo passed away today at the age of 75. I know I’m not alone in thinking that he should have received a share of the Nobel prize in 2008, which was awarded to Yoichiro Nambu (half the prize) and the other half was split between Makoto Kobayashi and Toshihide Maskawa.
As I wrote in 2008:
All three are extremely distinguished physicists and their contributions certainly deserve to be rewarded. But, in the case of Kobayashi and Maskawa, the Nobel Foundation has made a startling omission that I really can’t understand at all and which even threatens to undermine the prestige of the prize itself.The work for which these two were given half the Nobel Prize this year relates to the broken symmetry displayed by weak interactions between quarks. We now know that there are three generations of quarks, each containing quarks of two different flavours. The first generation contains the up (u) and the down (d), the second the strange (s) and the charmed (c), and the third has the bottom (b) and the top (t). OK, so the names are daft, but physicists have never been good at names.
The world of quarks is different to penetrate becauses quarks interact via the strong force which binds them close together into hadrons which are either baryons (three quarks) or mesons (a quark and an anti-quark).
But there are other kinds of particles too, the leptons. These are also arranged in three generations but each of these families contains a charged particle and a neutrino. The first generation is an electron and a neutrino, the second a muon and its neutrino, and the third has the tau and another neutrino. One might think that the three quark generations and the three lepton generations might have some deep equivalence between them, but leptons aren’t quarks so can’t interact at all by the strong interaction. Quarks and leptons can both interact via the weak interaction (the force responsible for radioactive beta-decay).
Weak interactions between leptons conserve generation, so the total number of particles of electron type is never changed (ignoring neutrino oscillations, which have only relatively recently been discovered). It seemed natural to assume that weak interactions between quarks should do the same thing, forbidding processes that hop between generations. Unfortunately, however, this is not the case. There are weak interactions that appear to convert u and/or d quarks into c and/or s quarks, but these seem to be relatively feeble compared to interactions within a generation, which seem to happen with about the same strength for quarks as they do for leptons. This all suggests that there is some sort of symmetry lurking somewhere in there, but it’s not quite what one might have anticipated.
The explanation of this was proposed by Nicola Cabibbo who, using a model in which there are only two quark generations, developed the idea that states of pure quark flavour (“u” or “d”, say) are not really what the weak interaction “sees”. In other words, the quark flavour states are not proper eigenstates of the weak interaction. All that is needed is to imagine that the required eigenstates are a linear combination of the flavour states and, Bob’s your uncle, quark generation needn’t be conserved. This phenomenon is called Quark Mixing. What makes it simple for only two generations is that it can be described entirely by one number: the Cabibbo angle, which measures how much the quark flavour basis is misaligned with the weak interaction basis. The angle is small so the symmetry is only slightly broken.
Kobayashi and Maskawa generalized the work of Cabibbo to the case of three quark generations. That’s actually quite a substantial task as the description of mixing in this case requires not just a single number but a 3×3 matrix each of whose entries is complex. This matrix is universally called the Cabibbo-Kobayashi-Maskawa (CKM) matrix and it now crops up all over the standard model of particle physics.
And there’s the rub. Why on Earth was Cabibbo not awarded a share of this year’s prize? I was shocked and saddened to find out that he’d been passed over despite the fact that his work so obviously led the way. I can think of no reason why he was omitted. It’s outrageous. I even feel sorry for Kobayashi and Maskawa, because there is certain to be such an outcry about this gaffe that it may detract from their success.
But really…
I hope, however, that controversy doesn’t intrude too much on what I hope will be the forthcoming celebration of Cabibbo’s immense contributions to particle physics. I’ll leave it to the experts to write more detailed appreciations that do better justice to his achievements. I’ll just say that I only met him once in real life, but found him charmingly modest and altogether quite delightful company. He will be greatly missed.
I feel obliged to pass on the news that the results of the Decadal Review of US Astronomy were announced yesterday. There has already been a considerable amount of reaction to what the Review Panel (chaired by the esteemed Roger Blandford) came up with from people much more knowledgeable about observational astronomy and indeed US Science Politics, so I won’t try to do a comprehensive analysis here. I draw your attention instead to the report itself (which you can download in PDF form for free) and Julianne Dalcanton’s review of, and comments on, the Panel’s conclusions about the priorities for space-based and ground-based astronomy for the next decade or so over on Cosmic Variance. There’s also a piece by Andy Lawrence over on The e-Astronomer’s blog. I’ll just mention that Top of the Pops for space-based astronomy is the Wide-Field Infrared Survey Telescope (WFIRST) which you can read a bit more about here, and King of the Castle for the ground-based programme is the Large Synoptic Survey Telescope (LSST). Both of these hold great promise for the area I work in – cosmology and extragalactic astrophysics – so I’m pleased to see our American cousins placing such a high priority on them. The Laser Interferometer Space Antenna (LISA), which is designed to detect gravitational waves, also did very well, which is great news for Cardiff’s Gravitational Physics group.
It will be interesting to see what effect – if any – these priorities have on the ranking of corresponding projects this side of the Atlantic. Some of the space missions involved in the Decadal Review in fact depend on both NASA and ESA so there clearly will be a big effect on such cases. For example, the proposed International X-ray Observatory (IXO) did less well than many might have anticipated, with clear implications for Europe (including the UK). The current landscape of X-ray astronomy is dominated by Chandra and XMM, both of which were launched in 1999 and which are both nearing the end of their operational lives. Since X-ray astronomy can only be done from space, abandoning IXO would basically mean the end of the subject as we know it, but the question is how to bridge the the gap between the end of these two missions and the start of IXO even if it does go ahead but not until long after 2020? Should we keep X-ray astronomers on the payroll twiddling their thumbs for the next decade when other fields are desperately short of manpower for science exploitation?
On a more general level, it’s not obvious how we should react when the US gives a high priority to a given mission anyway. Of course, it gives us confidence that we’re not being silly when very smart people across the Pond endorse missions and facilities similar to ones we are considering over here. However, generally speaking the Americans tend to be able to bring missions from the drawing board to completion much faster than we can in Europe. Just compare WMAP with Planck, for instance. Trying to compete with the US, rather than collaborate, seems likely to ensure only that we remain second best. There’s an argument, therefore, for Europe having a programme that is, in some respects at least, orthogonal to the United States; in matters where we don’t collaborate, we should go for facilities that complement rather than compete with those the Americans are building.
It’s all very well talking of priorities in the UK but we all know that the Grim Reaper is shortly going to be paying a visit to the budget of the agency that administers funding for our astronomy, STFC. This organization went through a financial crisis all of its very own in 2007 from which it is still reeling. Now it has to face the prospect of further savage cuts. The level of “savings” being discussed – at least 25% -means that the STFC management must be pondering some pretty drastic measures, even pulling out of the European Southern Observatory (which we only joined in 2002). The trouble is that most of the other ground-based astronomical facilities used by UK astronomers have been earmarked for closure, or STFC has withdrawn from them. Britain’s long history of excellence in ground-based astronomy now hangs in the balance. It’s scary.
I hope the government can be persuaded that STFC should be spared another big cut and I’m sure that there’s extensive lobbying going on. Indeed, STFC has already requested input to its plans for the ongoing Comprehensive Spending Review (CSR). With this in mind, the Royal Astronomical Society has produced a new booklet designed to point out the relevance of astronomy to wider society. However I can’t rid from my mind the memory a certain meeting in London in 2007 at which the STFC Chief Executive revealed the true scale of STFC’s problems. He predicted that things would be much worse at the next CSR, i.e. this one. And that was before the Credit Crunch, and the consequent arrival of a new government swinging a very large axe. I wish I could be optimistic but, frankly, I’m not.
When the CSR is completed then STFC will have yet again to do another hasty re-prioritisation. Their Science Board has clearly been preparing:
… Science Board discussed a number of thought provoking scenarios designed to explore the sort of issues that the Executive may be confronted with if there were to be a significant funding reduction as a result of the 2010 comprehensive spending review settlement. As a result of these deliberations Science Board provided the Executive with guidance on how to take forward this strategic planning.
This illustrates a big difference in the way such prioritisation exercises are carried out in the UK versus the USA. The Decadal Review described above is a high-profile study, carried out by a panel of distinguished experts, which takes detailed input from a large number of scientists, and which delivers a coherent long-term vision for the future of the subject. I’m sure not everyone agrees with their conclusions, but the vast majority respect its impartiality and level-headedness and have confidence in the overall process. Here in the UK we have “consultation exercises” involving “advisory panels” who draw up detailed advice which then gets fed into STFC’s internal panels. That bit is much like the Decadal Review. However, at least in the case of the last prioritisation exercise, the community input doesn’t seem to bear any obvious relationship to what comes out the other end. I appreciate that there are probably more constraints on STFC’s Science Board than it has degrees of freedom, but there’s no getting away from the sense of alienation and cynicism this has generated across large sections of the UK astronomy community.
The problem with our is that we always seem to be reacting to financial pressure rather than taking the truly long-term “blue-skies” view that is clearly needed for big science projects of the type under discussion. The Decadal Review, for example, places great importance on striking a balance between large- and small-scale experiments. Here we tend slash the latter because they’re easier to kill than the former. If this policy goes on much longer, in the long run we’ll end up a with few enormous expensive facilities but none of the truly excellent science that can be done from using smaller kit. A crucial aspect of this that that science seems to have been steadily relegated in importance in favour of technology ever since the creation of STFC. This must be reversed. We need a proper strategic advisory panel with strong scientific credentials that stands outside the existing STFC structure but which has real influence on STFC planning, i.e. one which plays the same role in the UK as the Decadal Review does in the States.
Assuming, of course, that there’s any UK astronomy left in the next decade…
In the Dark 