Author Archive

Astrophobos

Posted in Poetry with tags , , on June 23, 2012 by telescoper

In the midnight heavens burning
Thro’ ethereal deeps afar,
Once I watch’d with restless yearning
An alluring, aureate star;
Ev’ry eye aloft returning,
Gleaming nigh the Arctic car.

Mystic waves of beauty blended
With the gorgeous golden rays;
Phantasies of bliss descended
In a myrrh’d Elysian haze;
And in lyre-born chords extended
Harmonies of Lydian lays.

There (thought I) lies scenes of pleasure,
Where the free and blessed dwell,
And each moment bears a treasure
Freighted with a lotus-spell,
And there floats a liquid measure
From the lute of Israfel.

There (I told myself) were shining
Worlds of happiness unknown,
Peace and Innocence entwining
By the Crowned Virtue’s throne;
Men of light, their thoughts refining
Purer, fairer, than our own.

Thus I mus’d, when o’er the vision
Crept a red delirious change;
Hope dissolving to derision,
Beauty to distortion strange;
Hymnic chords in weird collision,
Spectral sights in endless range.

Crimson burn’d the star of sadness
As behind the beams I peer’d;
All was woe that seem’d but gladness
Ere my gaze with truth was sear’d;
Cacodaemons, mir’d with madness,
Thro’ the fever’d flick’ring leer’d.

Now I know the fiendish fable
That the golden glitter bore;
Now I shun the spangled sable
That I watch’d and lov’d before;
But the horror, set and stable,
Haunts my soul for evermore.

by H.P. Lovecraft (1890-1937)

“It’s a girl thing” is patronising drivel.

Posted in Uncategorized with tags , , , on June 22, 2012 by telescoper

This excruciating  video, produced under the auspices of the European Commission via “Women in Research and Innovation”,  is (I suppose) meant to encourage more young women to become scientists.

Based on the female scientists I know, and the general reaction to it on Twitter (see hashtag #sciencegirlthing) and elsewhere this morning, I’d say it’s more likely to make them throw a brick at their screens….

..and make the rest of us  wonder why the EU is wasting its money on tripe like this.

UPDATE: 23rd June. They seem to have removed the video. Good.
UPDATE to the UPDATE: 23rd June. It’s back again.

Health and Beauty

Posted in Uncategorized with tags , , on June 21, 2012 by telescoper

This picture, obtained from here, explains why I am so healthy and so beautiful…

A Return to O-levels?

Posted in Education, The Universe and Stuff with tags , , , , , , , on June 21, 2012 by telescoper

I woke up this morning as usual to the 7am news on BBC Radio 3, which included an item about how Education Secretary Michael Gove is planning to scrap the current system of GCSE Examinations and replace them with something more like the old GCE O-levels, which oldies like me took way back in the mists of time.

There is a particular angle to this in Wales, because Michael Gove doesn’t have responsibility for education here. That falls to the devolved Welsh Government, and in particular to Leighton Andrews. He’s made it quite clear on Twitter that he has no intention to take  Wales  back to O-levels. Most UK media sources – predominantly based in London – seem to have forgotten that Gove speaks for England, not for the whole United Kingdom.

This is not the central issue, however. The question is whether GCSEs are, as Michael Gove claims, “so bad that they’re beyond repair”. Politicians, teachers and educationalists are basically saying that students are doing better; others are saying that the exams are easier. It’s a shouting match that has been going for years and which achieves very little. I can’t add much to it either, because I’m too old to have done GCSEs – they hadn’t been invented then. I did O-levels.

It does, however, give me the excuse to show you  the O-level physics paper I took way back in 1979. I’ve actually posted this before, but it seems topical to put it up again:

You might want to compare this with a recent example of an Edexcel GCSE (Multiple-choice) Physics paper, about which I have also posted previously.

I think most of the questions in the GCSE paper are much easier than the O-level paper above. Worse, there are many that are so sloppily put together that they  don’t make any sense at all. Take Question 1:

I suppose the answer is meant to be C, but since it doesn’t say that A is the orbit of a planet, as far as I’m concerned it might just as well be D. Are we meant to eliminate D simply because it doesn’t have another orbit going through it?

On the other hand, the orbit of a moon around the Sun is in fact similar to the orbit of its planet around the Sun, since the orbital speed and radius of the moon around its planet are smaller than those of the planet around the Sun. At a push, therefore you could argue that A is the closest choice to a moon’s orbit around the Sun. The real thing would be something close to a circle with a 4-week wobble variation superposed.

You might say I’m being pedantic, but the whole point of exam questions is that they shouldn’t be open to ambiguities like this, at least if they’re science exams. I can imagine bright and knowledgeable students getting thoroughly confused by this question, and many of the others on the paper.

Here’s a couple more, from the “Advanced” section:

The answer to Q30 is, presumably, A. But do any scientists really think that galaxies are “moving away from the origin of the Big Bang”?  I’m worried that this implies that the Big Bang was located at a specific point. Is that what they’re teaching?

Bearing in mind that only one answer is supposed to be right, the answer to Q31 is presumably D. But is there really no evidence from “nebulae” that supports the Big Bang theory? The expansion of the Universe was discovered by observing things Hubble called “nebulae”..

I’m all in favour of school students being introduced to fundamental things such as cosmology and particle physics, but my deep worry is that this is being done at the expense of learning any real physics at all and is in any case done in a garbled and nonsensical way.

Lest I be accused of an astronomy-related bias, anyone care to try finding a correct answer to this question?

The more of this kind of stuff I see, the more admiration I have for the students coming to study physics and astronomy at University. How they managed to learn anything at all given the dire state of science education represented by this paper is really quite remarkable.

Ultimately, however, the issue is not whether we have GCSEs or O-level examinations. There’s already far too much emphasis in the education system on assessment instead of   learning. That runs all the way through schools and into the university system. The excessive time we spend examining students reduces what we can teach them and turns the students’ learning experience into something resembling a treadmill. I agree that we need better examinations than we have now, but we also need   fewer. And we need to stop being obsessed by them.

ESA Endorses Euclid

Posted in Euclid, Science Politics, The Universe and Stuff with tags , , , , , , on June 20, 2012 by telescoper

I’m banned from my office for part of this morning because the PHYSX elves are doing mandatory safety testing of all my electrical whatnots. Hence, I’m staying at home, sitting in the garden, writing this little blog post about a bit of news I found on Twitter earlier.

Apparently the European Space Agency, or rather the Science Programme Committee thereof, has given the green light to a space mission called Euclid whose aim is to “map the geometry of the dark Universe”, i.e. mainly to study dark energy. Euclid is an M-class mission, pencilled in for launch in around 2019, and it is basically the result of a merger between two earlier proposals, the Dark Universe Explorer (DUNE, intended to measure effects of weak gravitational lensing) and the Spectroscopic All Sky Cosmic Explorer (SPACE, to measure wiggles in the galaxy power spectrum known as baryon acoustic oscillations); Euclid will do both of these.

Although I’m not directly involved, as a cosmologist I’m naturally very happy to see this mission finally given approval. To be honest, I am a bit sceptical about how much light Euclid will actually shed on the nature of dark energy, as I think the real issue is a theoretical not an observational one. It will probably end up simply measuring the cosmological constant to a few extra decimal places, which is hardly the issue when the value we try to calculate theoretically is a over a hundred orders of magnitude too large! On the other hand, big projects like this do need their MacGuffin..

The big concern being voiced by my colleagues, both inside and outside the cosmological community, is whether Euclid can actually be delivered within the agreed financial envelope (around 600 million euros). I’m not an expert in the technical issues relevant to this mission, but I’m told by a number of people who are that they are sceptical that the necessary instrumental challenges can be solved without going significantly over-budget. If the cost of Euclid does get inflated, that will have severe budgetary implications for the rest of the ESA science programme; I’m sure we all hope it doesn’t turn into another JWST.

I stand ready to be slapped down by more committed Euclideans for those remarks.

A Cross Country Ban….

Posted in Uncategorized with tags , on June 20, 2012 by telescoper

Following on from the X-rating awarded to this blog by Orange Mobile, my learned colleague Dr Dread informs me that it is also banned from Cross Country Trains:

Inappropriate or malicious? Who, me?

The Higgs Buzz

Posted in The Universe and Stuff with tags , , , , on June 19, 2012 by telescoper

Reaction to rumours about the Higgs, and a not-entirely good-tempered comment thread about the ethics of blogging. All in a day’s work for a particle physicist, I guess! Read the inside story on this post…

..and if you read this article you’ll see where the rumour originated.

Matt Strassler's avatarOf Particular Significance

The rumors about the Higgs particle at the Large Hadron Collider [LHC] have begun again, and since that’s all anyone is going to want to talk about until we actually get the news for real, at the ICHEP conference in Melbourne in a couple of weeks, we may as well get started.

[This is especially true since we learned last year that some well-known non-particle-physicist bloggers have information pipelines directly into the experiments.  It is perhaps inevitable that there are scientists who see it in their best interest to subvert the scientific process.]

The current hot rumor is that the LHC experiments ATLAS and CMS have seen, in the new 2012 data, very roughly what they saw last December in the 2011 data, at least as far as the signal from a Higgs decaying to two photons (particles of light) in the mass range of 125 GeV/c2

View original post 1,101 more words

Opening Access – The Finch Report

Posted in Open Access with tags , , , on June 19, 2012 by telescoper

Just a quickie this morning for those of you who have been following the debate about Open Access to academic research. Yesterday saw the publication of the Finch Report which was commissioned by David Willetts at the end of 2011. Here’s part of the opening paragraph of the announcement:

The report of the Working Group chaired by Dame Janet Finch published on 18 June recommends a programme of action to enable more people to read and use the publications arising from research. Better, faster communication of research results will bring benefits for public services and for economic growth. It will also bring improved efficiency for researchers, and opportunities for more public engagement with research.

Sounds promising. Even more promising is the following statement you can find in the summary:

The principle that the results of research that has been publicly funded should be freely accessible in the public domain is a compelling one, and fundamentally unanswerable

However, it is a long report that also raises many difficulties, some real but many (in my opinion) imaginary. It will take a while to digest it and judge whether the momentum that seems to have been generated towards open access dissipates under pressure from the academic publishing industry, which has been lobbying vigorously in recent months. At first reading, however, I’m bound to say that it looks like a sell-out.

A particular worry is that the report favours the so-called “Gold” open access model in which authors pay up front to make their articles publicly available, rather than publishing them in journals to which access is restricted to subscribers. There’s a danger that this will simply provide the publishers with another way of profiteering and won’t save any money at all. In fact, as the Finch report says, phasing in such a system alongside the old one would cost an additional $50 million per year.

My favoured solution is to dispense with the academic journal racket altogether, and for researchers just to put their results on publicly accessible repositories, like the arXiv. Disciplines such as Physics and Astronomy could stop using journals immediately at no additional cost whatsoever, and with an enormous saving in library subscriptions. This option – the so-called “Green” Open Access – is favoured by most researchers but obviously not the academic publishing lobby. Of course this report could turn out to be an irrelevance, if UK researchers have the courage to go Green unilaterally.

I don’t really have time to do a full job on the Finch Report now, but fortunately you can find a number of commentaries already, including a blog piece by Stephen Curry, a piece by Alok Jha in the Grauniad, an item in the Times Higher, and an article on the BBC Website.

I feel I should also draw your attention to a related piece in the Daily Mail which, in a manner that’s typical for said organ, gets hold of the wrong end of the stick and proceeds to beat about the bush with it. At least it doesn’t claim that Open Access will have a devastating effect on house prices.

Anyway, I’m sure to return to this when I’ve had time to read the report thoroughly, but in the meantime please feel free to comment through the usual channel…

P.S. Let me also plug my recent piece on open access in the Guardian

Honours and Admissions

Posted in Politics, Science Politics with tags , , , on June 18, 2012 by telescoper

Time for a quick comment on the Queen Birthday Honours List for 2012 which, if you’re interested, you can download in full here.

The honours system must appear extremely curious to people from outside the United Kingdom. It certainly seems so to me. On the one hand, I am glad that the government has a mechanism for recognising the exceptional contributions made to society by certain individuals. Musicians, writers, sportsmen, entertainers and the like generally receive handsome financial rewards, of course, but that’s no reason to begrudge a medal or two in recognition of the special place they occupy in our cultural life.  It’s  good to see scientists recognized too, although they tend not to get noticed so much by the press.

First of all, therefore, let me congratulate space scientist, and occasional commenter on this blog, Professor Monica Grady on her award of a CBE. I also couldn’t resist commenting on the award of a knighthood to the Chair of the Science and Technology Facilities Council

..Professor Michael Sterling, who has turned round the Science and Technology Facilities Council

according to the official government announcement; the emphasis is mine. The phrase “turned around” is an interestingly frank way of putting it, and a refreshing admission from a very high level  that STFC was in disarray under its previous management.

Although I’m happy to see recognition given to such people, as I did last year on this occasion I can’t resist stating my objections to the honours system for the record. One is that the list of recipients  of certain categories of award is overwhelmingly dominated by career civil servants, for whom an “honour”  goes automatically with a given rank. If an honour is considered an entitlement in this way then it is no honour at all, and in fact devalues those awards that are  given on merit to people outside the Civil Service. Civil servants get paid for doing their job, so they should have no more expectation of an additional reward than anyone else.

Honours have relatively little monetary value on their own, of course so this is not question of financial corruption. An honour does, however, confer status and prestige on the recipient so what we have is a much more subtle form of sleaze. One wonders how many names listed in the current roll of honours are there because of political donations, for example.

I wouldn’t accept an honour myself, but that’s easy to say because I’m sure I’ll never be nominated for one. However, I imagine that even people like me who are against the whole system are probably still tempted to accept such awards when offered, as they generate good publicity for one’s field, institution and colleagues. Fortunately, having less than a cat in hell’s chance of being nominated, I’m never going to be tempted in that way!

Classical Fluids via Quantum Mechanics

Posted in The Universe and Stuff with tags , , , , , , on June 17, 2012 by telescoper

The subject of this post is probably a bit too technical to interest many readers, but I’ve been meaning to post something about it for a while and seem to have an hour or so to spare this morning so here goes. This is going to be a battle with the clunky WordPress latex widget too so please bear with me if it’s a little difficult to read.

The topic something I came across a while ago when thinking about the way the evolution of the matter distribution in cosmology is described in terms of fluid mechanics, but what I’m going to say is not at all specific to cosmology, and perhaps isn’t all that well known, so it might be of some interest to readers with a general physics background.

Consider a fluid with density \rho= \rho (\vec{x},t). The velocity of the fluid at any point is \vec{v}=\vec{v}(\vec{x},t). The evolution of such a fluid can be described by the continuity equation:

\frac{\partial \rho}{\partial t} + \vec{\nabla}\cdot (\rho\vec{v})= 0

and the Euler equation

\frac{\partial \vec{v}}{\partial t} + (\vec{v}\cdot\vec{\nabla})\vec{v} +\frac{1}{\rho} \vec{\nabla} P + \vec{\nabla} V = 0,

in which P is the fluid pressure (pressure gradients appear in the above equation) and V is a potential describing other forces on the fluid (in a cosmological context, this would include its self-gravity). To keep things as simple as possible, consider a pressureless fluid (as might describe cold dark matter) and restrict consideration to the case of a potential flow, i.e. one in which

\vec{v} = \vec{\nabla}\phi

where \phi=\phi(\vec{x},t) is a velocity potential; such a flow is curl-free. It is convenient to take the first integral of the Euler equation with respect to the spatial coordinates, which yields an equation for the velocity potential (cf. the Bernoulli equation):

\frac{\partial \phi}{\partial t} + \frac{1}{2} (\nabla \phi)^{2} + V=0.

The continuity equation becomes

\frac{\partial \rho}{\partial t} + \vec{\nabla}\cdot(\rho\vec{\nabla}\phi) = 0

This is all standard basic classical fluid mechanics. Now here’s the interesting thing. Introduce a new quantity \Psi defined by

\Psi(\vec{x},t) \equiv R\exp(i\phi/\nu),

in which R=R(\vec{x},t) and \nu is a constant. Using this construction, it turns out that

\rho = \Psi\Psi^{\ast}= |\Psi|^2=R^2.

After a little bit of fiddling around putting this in the previous equation you can obtain the following:

i\nu \frac{\partial \Psi}{\partial t} = -\frac{\nu^2}{2} \nabla^2{\Psi} + V\Psi + Q\Psi

which, apart from the last term Q and a slightly different notation, is identical to the Schrödinger equation of quantum mechanics; the term \nu would be  proportional to Planck’s constant h in that context, but in this context is a free parameter.

The mysterious term Q is pretty horrible:

Q = \frac{\nu^2}{2} \frac{\nabla^2 R}{R},

and it turns the Schrödinger equation into a non-linear equation, but its role can be understood by seeing what happens if you start with the normal single-particle Schrödinger equation and work backwards; this is the approach taken historically by David Bohm and others. In that case the term Q appears as a strange extra potential term in the Bernoulli equation which is sometimes called the quantum potential. In the context of fluid flow, however, the term describes  the the effect of pressure gradients that would arise if the fluid were barotropic. In the approach I’ve outlined, going in the opposite direction, this term is consequently sometimes called the “quantum pressure”. The parameter \nu controls the size of this term, which has the effect of blurring out the streamlines of the purely classical solution.

This transformation from classical fluid mechanics to quantum mechanics is not a new idea; in fact it goes back to Madelung who, in the 1920s, was trying to find a way to express quantum theory in the language of classical fluids.

What interested me about this approach, however, is more practical. It might seem strange to want transform relatively simple classical fluid-mechanical setup into a quantum-mechanical framework, which isn’t the obvious way to make progress, but there are a number of advantages of doing so. Perhaps chief among them is that the construction of \Psi means that the density \rho is guranteed positive definite; this means that a perturbation expansion of \Psi will not lead to unphysical negative densities in the same way that happens if perturbation theory is applied to \rho directly. This approach also has interesting links to other methods of studying the growth of large-scale structure in the Universe, such as the Zel’dovich approximation; the “waviness” controlled by the parameter \nu is useful in ensuring that the density does not become infinite at shell-crossing, for example.

Anyway, here are some links to references with more details:

http://adsabs.harvard.edu/abs/1993ApJ…416L..71W
http://adsabs.harvard.edu/abs/1997PhRvD..55.5997W
http://adsabs.harvard.edu/abs/2002MNRAS.330..421C
http://adsabs.harvard.edu/abs/2003MNRAS.342..176C
http://adsabs.harvard.edu/abs/2006JCAP…12..012S
http://adsabs.harvard.edu/abs/2006JCAP…12..016S
http://adsabs.harvard.edu/abs/2010MNRAS.402.2491J

I think there are many more ways this approach could be extended, so maybe this will encourage someone out there to have a look at it!