Archive for March, 2016

The Trouble with Hitomi

Posted in The Universe and Stuff with tags , , on March 31, 2016 by telescoper

One of the stories I’ve been following a bit while taking a break from blogging has been that of the Japanese X-ray satellite Hitomi (formerly known as ASTRO-H), which was launched into a low-Earth orbit on February 17th 2016, experienced a “communication anomaly” on Saturday March 26th. It has now become clear that this was more than a simple communications glitch. Astronomer Jonathan McDowell posted this diagram on Twitter that showed a sudden decrease in the orbital period of the satellite:CekOyLxXEAAeNxF

Students of orbital dynamics will know that a decrease in orbital period corresponds to a decrease in the semi-major axis of the orbit, so Hitomi actually fell during this episode. It dropped only slightly – look at the % change on the graph – but by enough to be very worrying.

The plot thickened still further when radar detected five pieces of debris near the satellite and visual observations indicated the spacecraft to be tumbling rapidly. That suggested a very grim picture.

Putting the evidence together it seems that some kind of explosive event – possibly connected with out-gassing of cryogenic material from one of the on-board experiments – had damaged the satellite, changed its orbit and set it spinning uncontrollably.

Since then ground stations have picked up some signals from Hitomi, which is good news,  but these broadcasts are just from the on-board beacon. It has not yet proved possible to communicate with the attitude control system which is the only way to get it back into a stable state.

Obviously it’s touch and go as to whether the Japanese Space Agency JAXA will be able to regain control of Hitomi, but at least there’s more hope than on Saturday when many of us thought the vehicle had fallen apart. In fact the pieces of debris reported may be rather small (ten cm or so is detectable) and the main body of the telescoper may be intact. Maybe.

Update: April 1st. Tracking facilities are now reporting 11 pieces of debris, and also suggesting the object whose period is plotted in the above graph may not be the main part of the spacecraft. This does not sound good.

Update: April 2nd. The debris from Hitomi has now spread out due to different orbital speeds. The two largest pieces are both spinning out of control. I would say at this point that hope of a recovery has now disappeared. It’s very sad.

How to cite social media in academic writing

Posted in Uncategorized on March 30, 2016 by telescoper

I have often wondered how to do this properly. Now I know!

I am told my blog has been cited in the literature a few times but I have been unable to find any evidence for this as I don’t think there’s any mechanism for tracking citations to blogs. Or is there?

Social Media for Learning

Image source: https://en.wikipedia.org/wiki/Wikipedia:Citation_needed Image source: https://en.wikipedia.org/wiki/Wikipedia:Citation_needed

Referencing and citation is an important part of any writing. This post looks at some recommendations and consideration when citing social media. Citations have several important purposes:

  • to uphold intellectual honesty (or avoiding plagiarism),
  • to attribute prior or unoriginal work and ideas to the correct sources, to allow the reader to determine independently whether the referenced material supports the author’s argument in the claimed way,
  • and to help the reader gauge the strength and validity of the material the author has used. (Wikipedia)

At Sheffield Hallam University (SHU) the Guide to Referencing offers detailed guidance for producing citations and references according to the Harvard method in the Harvard-SHU style recommended by the library. You may be asked to use another method, or a variation of the Harvard style. If this is the case, you may wish to refer to guidance that matches this style. However the recommendations below…

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Farewell, Independent, and thanks for all the dictionaries..

Posted in Biographical, Crosswords, Uncategorized with tags , , , , , on March 30, 2016 by telescoper

I thought I’d resume blogging activity rather gently with a short post to mark the end of an era. Both the Independent and the Independent on Sunday have ceased to exist, at least in their print editions.  It was about three years ago that I switched from the Observer to the Independent on Sunday, which involved switching from the Azed cryptic crossword to Beelzebub for my most testing weekly crossword challenge. I stopped doing the Saturday Prize Cryptic puzzle in the Saturday Guardian too, in favour of the Independent Saturday Prize crossword in the Independent which immediately paid dividends in terms of prizes!

For crossword aficianados both the Azed and Beelzebub crosswords are composed by strict adherents of the rules set by the great Ximenes and both feature grids with no black squares, in contrast to the more normal Everyman puzzle. Jonathan Crowther, who sets the Azed puzzles is the successor to Ximenes in the Observer; he’s been setting puzzles there since 1971.

Anyway, the last Independent on Sunday was published on Sunday 20th March and it included a list of the winners of the last two Beelzebub puzzles; the very final one was No. 1,358:

Beelzebub

It’s a nice way to mark the end of an era! One last dictionary to add to the collection. I’ve completely lost track of the number of books of words I’ve won from the weekly puzzles in the Independent, but it’s certainly more than 50. I’ve given many away but there’s still a large stack in Dorothy’s office.

Anyway, I spent some of my Easter weekend off doing the Guardian  prize crossword (extra-large size, but quite easy) followed by Everyman and Azed in the Observer. I guess that’s my diet from now on…

 

Interlude

Posted in Uncategorized on March 19, 2016 by telescoper

For reasons I’d rather not go into at the moment, I’ve decided to take a break from blogging for a while. I’ll probably be back after Easter, but in the meantime there will be a short intermission.

 

 

More fine structure silliness …

Posted in Bad Statistics, The Universe and Stuff with tags , on March 17, 2016 by telescoper

Wondering what had happened to claims of a spatial variation of the fine-structure constant?

Well, they’re still around but there’s still very little convincing evidence to support them, as this post explains…

R.I.P. Asa Briggs (1921-2016)

Posted in History with tags , , on March 16, 2016 by telescoper
ASA

Asa Briggs (1921-2016)

The frivolity of yesterday’s post it’s time today for a piece of sad news. Eminent historian and distinguished former Vice Chancellor Asa Briggs (Lord Briggs of Lewes) has passed away at the age of 94.

There will be many others who can comment more meaningfully on his immense contribution to academic research, but it seems to me that Asa Briggs was a rare example of a historian whose work transcended the boundaries of academic research. Even an ignorant astrophysicist like me has read his marvellous Social History of England , for example. He was Vice Chancellor of Sussex University from 1967 until 1976, but when he retired from his post as Provost of Worcester College, Oxford, in 1991, he lived in Lewes which is just a few miles up the road from the Falmer campus so his association with the University remained strong.

Having twice been based at Sussex during my career I was of course familiar with Asa’s name and work but it wasn’t until two years ago that I finally got to meet him, at a Commemoration Dinner in the Royal Pavilion. For some reason I was seated next to him at this event and we talked about a wide range of subjects, including football. He was quite frail at that time, but full of good humour and very friendly. In short he was excellent company and clearly a very nice man.

Rest in Peace Asa Briggs (1921-2016).

 

Cavete, Quod Idibus Martiis

Posted in Film, History with tags , , on March 15, 2016 by telescoper

Today is the Ides of March and we’re entering the final straight before crossing the finishing line of term and collapsing in a sweaty mess into the arms of the Easter holiday. I’ve been ridiculously busy today so, being too knackered to think of anything else to post, I thought I’d tap into a priceless bit of British cultural history relevant to this auspicious day.

This is from the First Folio Edition of Carry On Cleo, and stars the sublime Kenneth Williams as Julius Caesar delivering one of the funniest lines in the whole Carry On series. The joke may be nearly as old as me, but it’s still a cracker…

 

 

The Great Photon Escape

Posted in The Universe and Stuff with tags , on March 14, 2016 by telescoper

Although it won’t be launched for a few years yet, the communications team behind the James Webb Space Telescope project, or JSWST for short, is already gearing up. Here’s a nice video they’ve made which I came across the other day and thought I would share on here..

Far Out

Posted in Poetry with tags , , on March 14, 2016 by telescoper

Beyond the dark cartoons
Are darker spaces where
Small cloudy nests of stars
Seem to float on air.

These have no proper names:
Men out alone at night
Never look up at them
For guidance or delight,

For such evasive dust
Can make so little clear:
Much less is known than not,
More far than near.

by Philip Larkin (1922-85)

 

 

“British physics” – A Lesson from History

Posted in History, Politics, Science Politics, The Universe and Stuff with tags , , , , , , , , , , , , , , , , on March 13, 2016 by telescoper

The other day I came across the following tweet

The link is to an excellent piece about the history of European science which I recommend reading; as I do with this one.

I won’t pretend to be a historian but I can’t resist a comment from my perspective as a physicist. I am currently teaching a course module called Theoretical Physics which brings together some fairly advanced mathematical techniques and applies them to (mainly classical) physics problems. It’s not a course on the history of physics, but thenever I mention a new method or theorem I always try to say something about the person who gave it its name. In the course of teaching this module, therefore, I have compiled a set of short biographical notes about the people behind the rise of theoretical physics (mainly in the 19th Century). I won’t include them here – it would take too long – but a list  makes the point well enough: Laplace, Poisson,  Lagrange, Hamilton, Euler, Cauchy, Riemann, Biot, Savart, d’Alembert, Ampère, Einstein, Lorentz, Helmholtz, Gauss, etc etc.

There are a few British names too  including the Englishmen Newton and Faraday and the Scot Maxwell. Hamilton, by the way, was Irish. Another Englishman, George Green, crops up quite prominently too, for reasons which I will expand upon below.

Sir Isaac Newton is undoubtedly one of the great figures in the History of Science, and it is hard to imagine how physics might have developed without him, but the fact of the matter is that for a hundred years after his death in 1727 the vast majority of significant developments in physics took place not in Britain but in Continental Europe. It’s no exaggeration to say that British physics was moribund during this period and it took the remarkable self-taught mathematician George Green to breath new life into it.
I quote from History of the Theories of the Aether and Electricity (Whittaker, 1951) :

The century which elapsed between the death of Newton and the scientific activity of Green was the darkest in the history of (Cambridge) University. It is true that (Henry) Cavendish and (Thomas) Young were educated at Cambridge; but they, after taking their undergraduate courses, removed to London. In the entire period the only natural philosopher of distinction was (John) Michell; and for some reason which at this distance of time it is difficult to understand fully, Michell’s researches seem to have attracted little or no attention among his collegiate contemporaries and successors, who silently acquiesced when his discoveries were attributed to others, and allowed his name to perish entirely from the Cambridge tradition.

I wasn’t aware of this analysis previously, but it re-iterates something I have posted about before. It stresses the enormous historical importance of British mathematician and physicist George Green, who lived from 1793 until 1841, and who left a substantial legacy for modern theoretical physicists, in Green’s theorems and Green’s functions; he is also credited as being the first person to use the word “potential” in electrostatics.

Green was the son of a Nottingham miller who, amazingly, taught himself mathematics and did most of his best work, especially his remarkable Essay on the Application of mathematical Analysis to the theories of Electricity and Magnetism (1828) before starting his studies as an undergraduate at the University of Cambridge ,which he did at the age of 30. Lacking independent finance, Green could not go to University until his father died, whereupon he leased out the mill he inherited to pay for his studies.

Extremely unusually for English mathematicians of his time, Green taught himself from books that were published in France. This gave him a huge advantage over his national contemporaries in that he learned the form of differential calculus that originated with Leibniz, which was far more elegant than that devised by Isaac Newton (which was called the method of fluxions). Whittaker remarks upon this:

Green undoubtedly received his own early inspiration from . . . (the great French analysts), chiefly from Poisson; but in clearness of physical insight and conciseness of exposition he far excelled his masters; and the slight volume of his collected papers has to this day a charm which is wanting in their voluminous writings.

Great scientist though he was, Newton’s influence on the development of physics in Britain was not entirely positive, as the above quote makes clear. Newton was held in such awe, especially in Cambridge, that his inferior mathematical approach was deemed to be the “right” way to do calculus and generations of scholars were forced to use it. This held back British science until the use of fluxions was phased out. Green himself was forced to learn fluxions when he went as an undergraduate to Cambridge despite having already learned the better method.

Unfortunately, Green’s great pre-Cambridge work on mathematical physics didn’t reach wide circulation in the United Kingdom until after his death. William Thomson, later Lord Kelvin, found a copy of Green’s Essay in 1845 and promoted it widely as a work of fundamental importance. This contributed to the eventual emergence of British theoretical physics from the shadow cast by Isaac Newton. This renaissance reached one of its heights just a few years later with the publication a fully unified theory of electricity and magnetism by James Clerk Maxwell.

In a very real sense it was Green’s work that led to the resurgence of British physics during the later stages of the 19th Century, and it was the fact that he taught himself from French books that enabled him to bypass the insular attitudes of British physicists of the time. No physicist who has taken even a casual look at the history of their subject could possibly deny the immense importance of mainland Europe in providing its theoretical foundations.

Of course science has changed in the last two hundred years, but I believe that we can still learn an important lesson from this particular bit of history. Science moves forward when scientists engage with ideas and information from as wide a range of sources as possible, and it stagnates when it retreats into blinkered insularity. The European Union provides all scientific disciplines with a framework within which scientists can move freely and form transnational collaborations for the mutual benefit of all. We need more of this, not less. And not just in science.