Archive for May, 2013

An Apology: The Royal Institution

Posted in Uncategorized with tags , , , on May 21, 2013 by telescoper

Earlier this year, in common with other media, this blog pledged its support to a campaign to save the Royal Institution from financial oblivion. In doing so I may have given the impression that the Royal Institution is a venerable and  highly esteemed organization dedicated to the task of bring science closer to the public and inspiring future generations with its exciting range of outreach activities, including its famous public lectures.

However, in the light of the Royal Institution’s recent decision to trademark the phrase “Christmas Lectures” , I now realize that this was misleading and in fact the Royal Institution is just another rapaciously self-serving organization, run by small-minded buffoons, which is dedicated to nothing but its own self-aggrandizement. It has further become clear that the RI will do anything it can to maintain its cushy existence in a  fancy property in Mayfair to the detriment of all  outreach activities elsewhere, and  should therefore be shut down immediately as a threat to the future health of UK science.

Moreover, as a protest, this blog calls upon all University science departments in the United Kingdom to organize their own series of  Christmas Lectures Yuletide Discourses  under the title Not the Royal Institution Christmas Lectures, beginning each presentation with a lengthy preamble describing the unpleasant and idiotic actions of the Royal Institution and explaining why its Christmas Lectures® should be boycotted.

I hope this clarifies the situation.

P.S. For more blog outrage, see here, here here…. (cont., p94).

Heiliger Dankgesang

Posted in Music, Poetry with tags , , , , , on May 20, 2013 by telescoper

Not much time to post these days, what with one thing and another, but music is always a good standby. In fact I’ve had this at the back of my mind for some time; hearing it on the radio last week gave me the nudge I needed to post it. I always feel a but uncomfortable about posting just a movement from a classical piece, but I think it is justifiable in this case. This is the 3rd Movement of String Quartet No. 15 (in A minor) by Ludwig van Beethoven (Opus 132).

The third movement is headed with the words

Heiliger Dankgesang eines Genesenen an die Gottheit, in der lydischen Tonart

I take the liberty of translating the first two words, using my schoolboy German, as “A Holy Song of Thanksgiving”; Beethoven wrote the piece after recovering from a very serious illness which he had feared might prove fatal. The movement begins in a mood of quiet humility but slowly develops into a sense of hope and deeply felt joy. The most remarkable  thing about this movement to me, though,  is that the music possesses the same restorative powers that it was written to celebrate. This music has a therapeutic value all of its own.

I don’t know if William Wordsworth (of whose poetry I am also extremely fond) ever had the chance to hear Beethoven’s Quartet No. 15 , and in Tintern Abbey he was writing about the therapeutic power of nature rather than music, but surely the  “tranquil restoration” described in that poem is exactly the feeling  Beethoven achieves in his music:

These beauteous forms,
Through a long absence, have not been to me
As is a landscape to a blind man’s eye:
But oft, in lonely rooms, and ‘mid the din
Of towns and cities, I have owed to them
In hours of weariness, sensations sweet,
Felt in the blood, and felt along the heart;
And passing even into my purer mind,
With tranquil restoration: — feelings too

Of unremembered pleasure: such, perhaps,
As have no slight or trivial influence
On that best portion of a good man’s life,
His little, nameless, unremembered, acts
Of kindness and of love. Nor less, I trust,
To them I may have owed another gift,
Of aspect more sublime; that blessed mood,
In which the burthen of the mystery,
In which the heavy and the weary weight
Of all this unintelligible world,

Is lightened: — that serene and blessed mood,
In which the affections gently lead us on, —
Until, the breath of this corporeal frame
And even the motion of our human blood
Almost suspended, we are laid asleep
In body, and become a living soul:
While with an eye made quiet by the power
Of harmony, and the deep power of joy,
We see into the life of things.

All that matters in football….

Posted in Cricket, Football with tags , , , on May 19, 2013 by telescoper

..is the relative position of the two teams in 16th and 17th place in the final Premiership table!

league

Of course, it would have been more satisfying if Sunderland had finished one place lower but then you can’t have everything!

Anyway, that’s the Premiership over for another season. Time to concentrate on the cricket. If the Ashes Tests producing anything like today’s play against New Zealand then it should be an exciting summer!

The Threat to STEM from HEFCE’s Funding Policies

Posted in Education, Finance with tags , , , , , on May 19, 2013 by telescoper

In my job here as Head of the School of Mathematical and Physical Sciences (MPS)  at the University of Sussex, I’ve been been spending a lot of time recently on trying to understand the way the School’s budget works, sorting out what remains to be done for this financial year, and planning the budget for next year. In the course of doing all that it has become clear to me that the current funding arrangements from the Higher Education Funding Council for England (HEFCE) are extremely worrying for Science, Technology, Engineering and Mathematics (STEM) disciplines.

Before the introduction  of the £9K tuition fees this academic year (i.e. in the `old regime’), a University would receive income from tuition fees of up to £3375 per student and from a `unit of resource’ or `teaching grant’ that depends on the subject. As shown in the upper part of Table C below which is taken from a HEFCE document:

Budgets

In the old regime, the  maximum income per student in Physics was thus £8,269 whereas for a typical Arts/Humanities student the maximum was £5,700. That means there was a 45% difference in funding between these two types of subject. The reason for this difference is that subjects such as physics are much more expensive to teach. Not only do disciplines like physics require expensive laboratory facilities (and associated support staff), they also involve many more contact hours between students and academic staff than in, e.g. an Arts subject.  However, the differential is not as large as you might think: there’s only a factor two difference in teaching grant between the lowest band (D, including Sociology, Economics, Business Studies, Law and Education) and the STEM band B (including my own subject, Physics). The real difference in cost is much larger than that, and not just because science subjects need laboratories and the like.

To give an example, I was talking recently to a student from a Humanities department at a leading University (not my employer). Each week she gets 3 lectures and one two-hour seminar, the latter  usually run by a research student. That’s it for her contact with the department. That meagre level of contact is by no means unusual, and some universities offer even less tuition than that.

In my School, MPS, a typical student can expect around 20 contact hours per week including lectures, exercise classes, laboratory sessions, and a tutorial (usually in a group of four). The vast majority of these sessions are done by full-time academic staff, not PDRAs or PhD students, although we do employ such folks in laboratory sessions and for a very small number of lectures. It doesn’t take Albert Einstein to work out that 20 hours of staff time costs a lot more than 3, and that’s even before you include the cost of the laboratories and equipment needed to teach physics.

Now look at what happens in the `new regime’, as displayed in the lower table in the figure. In the current system, students still pay the same fee for STEM and non-STEM subjects (£9K in most HEIs) but the teaching grant is now £1483 for Physics and nothing at all for Bands C and D. The difference in income is thus just £1,483 or in percentage terms, a difference of just 16.4. Worse than this, there’s no requirement that this extra resource be spent on the disciplines with which it is associated anyway. In most universities, all the tuition income goes into central coffers and is dispersed to Schools and Departments according to the whims of the University Management.

Of course the new fee levels have led to an increase in income to Universities across all disciplines, which is welcome because it should allow institutions to improve the quality of their teaching bu purchasing better equipment, etc. But the current arrangements as a powerful disincentive for a university to invest in expensive subjects, such as Physics, relative to Arts & Humanities subjects such as English or History. It also rips off  staff and students in those disciplines, the students because they are given very little teaching in return for their fee, and the staff because we have to work far harder than our colleagues in other disciplines, who  fob off  most of what little teaching their supposed to do onto PhD students badged as Teaching Assistants. It is fortunate for this country that scientists working in its universities show such immense dedication to teaching as well as research that they’re prepared to carry on working in a University environment that is so clearly biased against STEM disciplines.

To get another angle on this argument, consider the comments made by senior members of the legal profession who are concerned about the drastic overproduction of law graduates. Only about half those doing the Bar Professional Training Course after a law degree stand any chance of getting a job as a lawyer in the UK. Contrast this with the situation in science subjects, where we don’t even produce enough graduates to ensure that schools have an adequate supply of science teachers. The system is completely out of balance. Here at Sussex, only about a quarter of students take courses in STEM subjects; nationally the figure is even lower, around 20%…

I don’t see anything on the horizon that will alter this ridiculous situation. STEM subjects will continue to be stifled as universities  follow the incentive to invest in cheaper subjects and will continue to overproduce graduates in other areas. The present Chief Executive of HEFCE is stepping down. Will whoever takes over from him have the guts to do anything about this anti-STEM bias?

I doubt the free-market ideologues in Westminster would even think of intervening either, because the only two possible changes are: (i) to increase the fee for STEM subjects relative to others; and (ii) to increase the teaching grant. Option (i) would lead to a collapse in demand for the very subjects it was intended to save and option (ii) would involve increasing public expenditure, which is anathema to the government even if it is an investment in the UK’s future. Or maybe it’s making a complete botch of the situation deliberately, as part of a cunning plan to encourage universities to go private?

All models are wrong

Posted in The Universe and Stuff with tags , , , , , , , , , on May 17, 2013 by telescoper

I’m back in Cardiff for the day, mainly for the purpose of attending presentations by a group of final-year project students (two of them under my supervision, albeit now remotely).  One of the talks featured a famous quote by the statistician George E.P. Box:

Essentially, all models are wrong, but some are useful.

I agree with this, actually, but only if it’s not interpreted in a way that suggests that there’s no such thing as reality and/or that science is just a game.  We may never achieve a perfect understanding of how the Universe works, but that’s not the same as not knowing anything at all. 

A familiar example that nicely illustrates my point  is the London Underground or Tube map. There is a fascinating website depicting the evolutionary history of this famous piece of graphic design. Early versions simply portrayed the railway lines inset into a normal geographical map which made them rather complicated, as the real layout of the lines is far from regular. A geographically accurate depiction of the modern tube network is shown here which makes the point:

geo_tubemap

A revolution occurred in 1933 when Harry Beck compiled the first “modern” version of the map. His great idea was to simplify the representation of the network around a single unifying feature. To this end he turned the Central Line (in red) into a straight line travelling left to right across the centre of the page, only changing direction at the extremities. All other lines were also distorted to run basically either North-South or East-West and produce a much more regular pattern, abandoning any attempt to represent the “real” geometry of the system but preserving its topology (i.e. its connectivity).  Here is an early version of his beautiful construction:

Note that although this a “modern” map in terms of how it represents the layout, it does look rather dated in terms of other design elements such as the border and typefaces used. We tend not to notice how much we surround the essential things with embellishments that date very quickly.

More modern versions of this map that you can get at tube stations and the like rather spoil the idea by introducing a kink in the central line to accommodate the complexity of the interchange between Bank and Monument stations as well as generally buggering about with the predominantly  rectilinear arrangement of the previous design:

I quite often use this map when I’m giving popular talks about physics. I think it illustrates quite nicely some of the philosophical issues related with theoretical representations of nature. I think of theories or models as being like maps, i.e. as attempts to make a useful representation of some  aspects of external reality. By useful, I mean the things we can use to make tests. However, there is a persistent tendency for some scientists to confuse the theory and the reality it is supposed to describe, especially a tendency to assert there is a one-to-one relationship between all elements of reality and the corresponding elements in the theoretical picture. This confusion was stated most succintly by the Polish scientist Alfred Korzybski in his memorable aphorism :

The map is not the territory.

I see this problem written particularly large with those physicists who persistently identify the landscape of string-theoretical possibilities with a multiverse of physically existing domains in which all these are realised. Of course, the Universe might be like that but it’s by no means clear to me that it has to be. I think we just don’t know what we’re doing well enough to know as much as we like to think we do.

A theory is also surrounded by a penumbra of non-testable elements, including those concepts that we use to translate the mathematical language of physics into everday words. We shouldn’t forget that many equations of physics have survived for a long time, but their interpretation has changed radically over the years.

The inevitable gap that lies between theory and reality does not mean that physics is a useless waste of time, it just means that its scope is limited. The Tube  map is not complete or accurate in all respects, but it’s excellent for what it was made for. Physics goes down the tubes when it loses sight of its key requirement, i.e. to be testable, and in order to be testable it has to be simple enough to calculate things to be compared with observations. In many cases that means a simplified model is perfectly adequete.

Another quote by George Box expands upon this point:

Remember that all models are wrong; the practical question is how wrong do they have to be to not be useful.

In any case, an attempt to make a grand unified theory of the London Underground system would no doubt produce a monstrous thing so unwieldly that it would be useless in practice. I think there’s a lesson there for string theorists too…

Many modern-day physicists are obsessed with the idea of a “Theory of Everything” (or TOE). Such a theory would entail the unification of all physical theories – all laws of Nature, if you like – into a single principle. An equally accurate description would then be available, in a single formula, of phenomena that are currently described by distinct theories with separate sets of parameters. Instead of textbooks on mechanics, quantum theory, gravity, electromagnetism, and so on, physics students would need just one book. But would such a theory somehow be  physical reality, as some physicists assert? I don’t think so. In fact it’s by no means clear to me that it would even be useful..

Proletarian Democracy Eurovision Song Contest Preview (Part 1)

Posted in Politics with tags , , , on May 16, 2013 by telescoper

As we approach the evening of interminable tedium that is the Eurovision Song Contest, it’s refreshing to stumble across a Blog post that reveals the competitions true political and cultural significance…

Proletarian Democracy

The Eurovision Song Contest, cultural Marxism’s flagship spectacle, is a highlight in every communist’s calendar, or should be. We proudly present part 1 of the official Proletarian Democracy preview of all the entries. The following score system applies.

PD eurovision score table

1: Austria – Natalia Kelly – Shine

When hurt is all you’re feeling, your heart is slowly bleeding
The only memories to hold on to
When you almost stop believing, you’re cold, alone and freezing
You think you’re lost and don’t know where to go
Look up to the starlit sky, reignite the fire
You will shine, shine and fight the shadows in the sky

What’s it about?
The loneliness of the far-left paper seller.

Sounds like:
A somnambulant Travis.

VERDICT

Little bit communism

2: Estonia – Birgit Õigemeel – Et Uus Saaks Alguse

The curtain is being raised once more
The second act is starting, where I pick myself up and dust myself down

View original post 1,620 more words

How to make a knotted vortex ring

Posted in The Universe and Stuff with tags , , , , on May 15, 2013 by telescoper

Not long ago I posted a short item about the physics of vortex rings. More recently I stumbled across this video that shows how University of Chicago physicists have succeeded in creating a vortex knot—a feat akin to tying a smoke ring into a knot. Linked and knotted vortex loops have existed in theory for more than a century, but creating them in the laboratory had previously eluded scientists. I stole that bit shamelessly from the blurb on Youtube, by the way. I’m not sure whether knotting a vortex tube has any practical applications, but then I don’t really care  much about that because it’s fun!

Lines Composed upon the Relegation of Wigan Athletic from the Premiership

Posted in Football, Poetry with tags , , on May 15, 2013 by telescoper

So farewell, then,
Wigan Athletic.
You weren’t
Athletic enough,
Apparently.

Keith’s mum says
Wigan is not
In the Midlands.
But she’s wrong.
Obviously.

by Peter Coles (aged nearly 50).

Hall and Knight (or `z + b + x = y + b + z’)

Posted in The Universe and Stuff with tags , , , , on May 14, 2013 by telescoper

This poem will be a bit of a puzzle to younger readers, so I’ll just explain that Messrs Hall & Knight mentioned in the poem were the authors of a famous textbook about algebra “Elementary Algebra for Schools” that first went into publication in the 19th Century (1885, I think) and is still in press over a century later. It’s a classic book, fully meriting a celebration in verse, even if it’s a bit tongue-in-cheek!

When he was young his cousins used to say of Mr Knight:
‘This boy will write an algebra – or looks as if he might.’
And sure enough, when Mr Knight had grown to be a man,
He purchased pen and paper and an inkpot, and began.

But he very soon discovered that he couldn’t write at all,
And his heart was filled with yearnings for a certain Mr Hall;
Till, after many years of doubt, he sent his friend a card:
‘Have tried to write an Algebra, but find it very hard.’

Now Mr Hall himself had tried to write a book for schools,
But suffered from a handicap: he didn’t know the rules.
So when he heard from Mr Knight and understood his gist,
He answered him by telegram: ‘Delighted to assist.’

So Mr Hall and Mr Knight they took a house together,
And they worked away at algebra in any kind of weather,
Determined not to give up until they had evolved
A problem so constructed that it never could be solved.

‘How hard it is’, said Mr Knight, ‘to hide the fact from youth
That x and y are equal: it is such an obvious truth!’
‘It is’, said Mr Hall, ‘but if we gave a b to each,
We’d put the problem well beyond our little victims’ reach.

‘Or are you anxious, Mr Knight, lest any boy should see
The utter superfluity of this repeated b?’
‘I scarcely fear it’, he replied, and scratched this grizzled head,
‘But perhaps it would be safer if to b we added z.’

‘A brilliant stroke!’, said Hall, and added z to either side;
Then looked at his accomplice with a flush of happy pride.
And Knight, he winked at Hall (a very pardonable lapse).
And they printed off the Algebra and sold it to the chaps.

by E. V. Rieu (1887-1972)

The Mystery of Cosmic Magnetism

Posted in The Universe and Stuff with tags , , , , , , on May 13, 2013 by telescoper

I came across an article in New Scientist recently on the topic of cosmological magnetism. The piece is about an article by Leonardo Campanelli, which is available on the arXiv and which is apparently due to be published in Physical Review Letters. So it must be right.

Here’s the abstract

We calculate, in the free Maxwell theory, the renormalized quantum vacuum expectation value of the two-point magnetic correlation function in de Sitter inflation. We find that quantum magnetic fluctuations remain constant during inflation instead of being washed out adiabatically, as usually assumed in the literature. The quantum-to-classical transition of super-Hubble magnetic modes during inflation, allow us to treat the magnetic field classically after reheating, when it is coupled to the primeval plasma. The actual magnetic field is scale independent and has an intensity of few \times 10^(-12) G if the energy scale of inflation is few \times 10^(16) GeV. Such a field account for galactic and galaxy cluster magnetic fields.

So why is this interesting? Let me explain….

If you’re stuck for a question to ask at the end of an astronomy seminar and don’t want to reveal the fact that you were asleep for most of it, there are some general questions that you can nearly always ask regardless of the topic of the talk without appearing foolish. A few years ago, “how would the presence of dust affect your conclusions?” was quite a good one, but the danger these days is that with the development of far-infrared and submillimetre instrumentation and the proliferation of people using it, this could actually have been the topic of the talk you just dozed through. However, no technological advances have threatened the viability of another old stalwart: “What about magnetic fields?”.

In theory, galaxies condense out of the Big Bang as lumps of dark matter. Seeded by primordial density fluctuations and amplified by the action of gravity, these are supposed to grow in a hierarchical, bottom-up fashion with little blobs forming first and then merging into larger objects. The physics of this process is relatively simple (at least if the dark matter is cold) as it involves only gravity.

But, by definition, the dark matter can’t be seen. At least not directly, though its presence can be inferred indirectly by dynamical measurements and gravitational lensing. What astronomers generally see is starlight, although it often arrives at the telescope in an unfamiliar part of the spectrum owing to the redshifting effect of the expansion of the Universe. The stars in galaxies sit inside the blobs of dark matter, which are usually called “haloes” although blobs is a better name. In art the whole purpose of a halo is that you can see it.

How stars form is a very complicated question to answer even when you’re asking about nearby stellar nurseries like the Orion Nebula. The basic idea is that a gas cloud cools and contracts, radiating away energy until it gets sufficiently hot that nuclear burning switches on and pressure is generated that can oppose further collapse. The early stages of this processs, though, involve very many imponderables. Star formation doesn’t just involve gravity but lots of other processes, including additional volumes of Landau & Lifshitz, such as hydrodynamics, radiative transfer and, yes, magnetic fields. Naively, despite the complicated physics, it might still be imagined that stars form in the little blobs of dark matter first and then gradually get incorporated in larger objects.

Unfortunately, it is becoming increasingly obvious that this naive picture doesn’t quite work. Deep surveys of galaxies suggest that the most massive galaxies formed their stars quite early in the Big Bang and have been relatively quiescent since then, while smaller objects contain younger stars. In other words, pretty much the opposite of what one might have thought. This phenomenon (known as “downsizing”) suggests that something inhibits star formation early on in all but the largest of the largest haloes. It could be that powerful feedback from activity in the nuclear regions associated with a central black hole might do this, or it could be something a little less exotic such as stellar winds. Or it could be that the whole scheme is wrong in a more fundamental way. I personally wouldn’t go so far as to throw out the whole framework, as it has scored many successes, but it is definitely an open question what is going on.

A paper  in Nature a few years ago by Art Wolfe and collaborators revealed the presence of an enormously strong magnetic field in a galaxy at the relatively high redshift of 0.692. Actually it’s about 84 microGauss. OK, so this is just one object but the magnetic field in it is remarkably strong. It could be a freak occurrence resulting from some kind of shock or bubble, but it does seem to fit in a pattern in which young galaxies generally seem to have much higher magnetic fields than previously expected. Obviously we need to know how many more such magnetic monsters are lurking out there.

So why are these results so surprising? Didn’t we already know galaxies have magnetic fields in them?

Well, yes we did. The Milky Way has a magnetic field with a strength of about 10 microGauss, much lower than that discovered by Wolfe et al. But the point is that if we understand them properly, galactic magnetic fields are supposed to be have been much lower in the past than they are now. The standard theoretical picture is that a (tiny) initial seed field is amplified by a kind of dynamo operating by virtue of the strong differential rotation in disk galaxies. This makes the field grow exponentially with time so that only a few rotations of the galaxy are needed to make a large field out of a very small one. Eventually this dynamo probably quenches when the field has an energy density comparable to the gas in the galaxy (which is roughly the situation we find in our own Galaxy).

Hopefully you now see the problem. If the field is being wound up quickly then younger galaxies (those whose light comes to us from a long way away) should have much smaller magnetic fields than nearby ones. But they don’t seem to behave in this way.

A few years ago, I wrote a paper about a model in which the galactic fields weren’t produced by a dynamo but were primordial in origin and quite large from the start. If that’s the case then the magnetic field need not evolve as quickly as it needs to if the initial field is very tiny.

The problem is that it has previously been thought very difficult for any cosmological model involving inflation to generate a significant primordial magnetic field without invoking very exotic physics, such as breaking the conformal invariance of electrodynamics (which would mean, among other things, giving the photon a rest mass).

The interesting thing about Campanelli’s paper is that it suggests a straightforwardmechanism for inflation to generate interesting magnetic phenomena. I’m not an expert on the techniques used in this paper, so can’t comment on the accuracy of the calculations. I’d be very grateful for any comments on this, actually. Me, I’m an old fogey who’s very suspicious of anything that relies too heavily on renormalization. I do however agree with Larry Widrow, quoted in the New Scientist piece.

But even if primordial magnetic fields can be generated by inflation, their impact on the origin and evolution of galaxies and other cosmic structures remains unsolved. Although we know magnetism exists, it is notoriously difficult to understand its behaviour when it is coupled to all the other messy things we have to deal with in astrophysics. It’s a kind of polar opposite of dark matter, which we don’t know (for sure) exists but which only acts through gravity, so its behaviour is easier to model. This is the main reason why cosmological theorists prefer to think about dark matter rather than magnetic fields. I’d hazard a guess that this is one problem that won’t be resolved soon either. Things are complicated enough already!

It is also worth considering the possibility that magnetic fields might play a role in moderating the processes by which gas turns into stars within protogalaxies. At the very least, a magnetic field generates stresses that influence the onset of collapse. Although the evidence is mounting that they may be important, it is still by no means obvious that magnetic fields do provide the required missing link between dark matter haloes and stars. On the other hand, we now have fewer reasons for ignoring them.