Archive for March, 2017

Recycled Bach

Posted in Music with tags , , , , , , on March 31, 2017 by telescoper

I had the office to myself this morning so I was listening to Essential Classics presented by Rob Cowan on BBC Radio 3 earlier on. During the course of the programme he pointed out that Johann Sebastian Bach was not averse to a bit of recycling and gave the following example. I’m sure that everyone has heard of Bach’s Mass in B Minor (BWV232), which is widely regarded as one of the greatest works ever composed in the entire history of music.

However, although this work is often depicted as a kind of culmination of Bach’s career as a composer and it wasn’t completed until 1749 (the year before Bach’s death), many sections were in fact recycled from much earlier compositions.

For example, give a listen to this. It is the Aria Ach, bleibe doch, mein liebstes Leben from the Cantata Lobet Gott in seinen Reichen (BWV11), often called the Ascension Oratorio, which was first performed in 1735. Apart from the fact that it sets a different text in a different language – the B Minor Mass is a setting of the complete `Ordinary’ of the Latin mass – and there are one or two musical differences here and there, this is instantly recognizable as an earlier incarnation of the sublime Agnus Dei from the B Minor Mass..

Oh, and if you’ve got half an hour to spare you could watch this video of a sparkly and sprightly performance of the entire cantana.

 p.s. It’s Bach’s birthday today: he was born on March 31 1685.

 

 

A Question of Equilibrium

Posted in Cute Problems with tags , on March 30, 2017 by telescoper

It’s been quite a while since I’ve been able to find time to post any items in the cute problems folder, and I don’t have much time today either, but here’s a quickie. You may well find this a lot harder than it looks at first sight. At least I did!

An isolated system consists of two identical components, each of constant heat capacity C, initially held at temperatures T1 and T2 respectively. What is the maximum amount of work that can be extracted from the system by allowing the  two components to reach equilibrium with each other?

As usual, answers through the comments box please. There is no prize, even if you’re right.

 

 

We’ll Be Together Again

Posted in Jazz, Politics with tags , , , , , on March 29, 2017 by telescoper

So, we’ve come to it at last.

At 12.30 BST the Prime Minister’s letter invoking Article 50 of the Lisbon Treaty will be delivered to the President of the European Council, Donald Tusk. This will begin the process by which the United Kingdom leaves the European Union. It also begins the process of dismantling the United Kingdom itself. Scottish independence is now an inevitability as is, probably on a slightly longer timescale, the reunification of Ireland.

I am sad beyond words that this country has taken this path to self-destruction, but can only hope that we eventually see sense and change or mind at some point in the next two years, or return to the fold at some later stage.

No artist was better at conveying a sense of tragedy and loss through their music than Billie Holiday, and here’s a track by her that perfectly expresses my feelings at this bleak time:

No tears, no fears
Remember there’s always tomorrow
So what if we have to part
We’ll be together again

 

 

The Threepenny Opera

Posted in Biographical with tags , on March 28, 2017 by telescoper

Yesterday’s announcement of the launch of a new 12-sided pound coin reminded me of the old three-penny bit, which had the same number of sides but a different composition and overall design.

Threepenny bit

The old coin had been around since the 16th century, but was phased out when the United Kingdom switched to decimal currency back in 1971. Youngsters won’t remember the old currency, but a pound used to be divided into 20 shillings, each of which was 12 `old’ pence. A threepenny bit was therefore worth 1/80 of a pound sterling. Other old coins of note were the tanner (sixpence), the shilling (one bob) and the half-crown (‘two and six’, i.e. two shillings and sixpence). There was also a penny (which was a rather large coin), the halfpenny and even the farthing (half a halfpenny). Pound coins didn’t exist in those days, only pound notes. There were also `ten bob’ notes, corresponding to half a pound, which converted to 50p coins on decimalization.

Tomorrow the Prime Minister of the United Kingdom will trigger Article 50 of the Lisbon Treaty which will begin our country’s regression into the past. I can’t help feeling that it won’t be long until go back to the old money too.

Anyway, I have specific memories of the threepenny bit because once, when I was little, I swallowed one and had to go to hospital. Don’t ask me how or why this happened. I didn’t feel particularly unwell but they did an X-ray and there it was, bold as brass, in all its dodecagonal glory. I don’t remember the eventual emergence of the coin but when we went back to the hospital a few days later it had vanished from the radar. Nature had clearly taken its course.

That little episode wasn’t as funny as my cousin Gary, who once had to go to hospital because he got a marble stuck up his nose. In Newcastle the word for a a marble is a `liggy’, by the way. I was with Gary when this happened (!) and ended up going along to casualty with him. He was in some discomfort as we sat in the waiting room, then a rather burly nurse came in. She looked at him carefully, then raised her right hand and delivered a resounding smack on the back of his head, whereupon the liggy stotted out across the floor. Job done.

Is there a kinematic backreaction in cosmology?

Posted in The Universe and Stuff with tags , , , , , on March 28, 2017 by telescoper

I just noticed that a paper has appeared on the arXiv with the confident title There is no kinematic backreaction. Normally one can be skeptical about such bold claims, but this one is written by Nick Kaiser and he’s very rarely wrong…

The article has a very clear abstract:

Kaiser

This is an important point of debate, because the inference that the universe is dominated by dark energy (i.e. some component of the cosmic energy density that violates the strong energy condition) relies on the assumption that the distribution of matter is homogeneous and isotropic (i.e. that the Universe obeys the Cosmological Principle). Added to the assumption that the large-scale dynamics of the Universe are described by the general theory of relativity, this means that we evolution of the cosmos is described by the Friedmann equations. It is by comparison with the Friedmann equations that we can infer the existence of dark energy from the apparent change in the cosmic expansion rate over time.

But the Cosmological Principle can only be true in an approximate sense, on very large scales, as the universe does contain galaxies, clusters and superclusters. It has been a topic of some discussion over the past few years as to whether the formation of cosmic structure may influence the expansion rate by requiring extra terms that do not appear in the Friedmann equations.

Nick Kaiser says `no’. It’s a succinct and nicely argued paper but it is entirely Newtonian. It seems to me that if you accept that his argument is correct then the only way you can maintain that backreaction can be significant is by asserting that it is something intrinsically relativistic that is not covered by a Newtonian argument. Since all the relevant velocities are much less than that of light and the metric perturbations generated by density perturbations are small (~10-5) this seems a hard case to argue.

I’d be interested in receiving backreactions to this paper via the comments box below.

Data-Intensive Physics and Astrophysics

Posted in Biographical, Education with tags , , , , on March 27, 2017 by telescoper

One of the jobs I’ve got in my current position (which is divided between the School of Physics & Astronomy and the Data Innovation Research Institute) is to develop new teaching activities, focussing on interdisciplinary courses involving a Data Science component. Despite the fact that I only started work developing them in September last year the first two such courses have been formally approved and are now open for admission of new students to begin their courses in September 2017. That represents a very fast-track for such things as there are many hurdles to get over in preparing new courses. Meeting the deadlines hasn’t been easy, which is largely why I’ve been whingeing on here about workload issues, but we’re finally there!

The two new courses are both at Masters (MSc) level and are called Data-Intensive Physics and Data-Intensive Astrophysics and they are both taught jointly by staff in the School of Physics and Astronomy and the School of Computer Science and Informatics in a kind of major/minor combination.

The aim of these courses is twofold.

One is to provide specialist postgraduate training for students wishing to go into academic research in a ‘data-intensive’ area of physics or astrophysics, by which I mean a field which involves the analysis and manipulation of very large or complex data sets and/or the use of high-performance computing for, e.g., simulation work. There is a shortage of postgraduates with the necessary combination of skills to being PhD programmes in such areas, and we plan to try to fill the gap with these courses.

The other aim is to cater for students who may not have made up their mind whether to go into academic research, but wish to keep their options open while pursuing a postgraduate course. The unique combination of physics/astrophysics and computer science will give those with these qualifications the option of either continuing or going into another sphere of data-intensive research in the wider world of Big Data.

We’ll be putting out some official promotional materials for these courses very soon, but I thought I’d mention them here partly because it might help with recruitment and partly because I’m so relieved that they’ve actually made it into the prospectus.

 

Tim Garland Electric Quartet

Posted in Jazz with tags , , , on March 27, 2017 by telescoper

Time for  a quick report on a superb concert I attended on Friday evening, at the Royal Welsh College of Music and Drama, by the Tim Garland Electric Quartet. I don’t get to hear anything like as much live jazz as I would like to, but did manage to get my act together in time for this one.

The band consisted of Tim Garland (tenor & soprano saxophones and bass clarinet, Jason Rebello (keyboards), Ant Law (acoustic and electric guitars) and Asaf Sirkis (drums and other percussion). Although named the ‘Electric Quartet’ it turned out to have a larger acoustic component than I expected, because Jason Rebello had clearly taken a shine to the splendid grand piano that had been provided and did much of his work on that rather than the synthesizers and other electronica he had brought with him. I think the music we heard therefore had a different flavour from similar concerts they have been doing around the country, echoing the words of Shelly Manne (about jazz musicians): “We never play anything the same way once.”

Here’s a little intro to the band I found on Youtube:

As well as being a very fine soloist and bandleader, Tim Garland is also a prolific composer and many of the pieces played at this concert were his own original compositions. My favourites of these were the hauntingly evocative Tyne Song (written in celebration of the town of my birth, which brought a tear to my eye) and The Eternal Greeting , which is from the band’s latest album One. They also played lovely versions of two familiar jazz standards, Good Morning Heartache (made famous by Billie Holiday) and the Miles Davis & Bill Evans classic Blue in Green. The programme was very varied, with middle-eastern, classical and flamenco influences, as well as the Jazz/Rock Fusion of the 80s, and the overall standard of music exceptionally high and with a wonderful sense of freshness and sponteneity. Tim Garland also introduced each number in a very engaging and laid-back way, pointing out little items of interest about the music.

I loved every minute and it served to remind me how much I love to hear live jazz. I must make more of an effort to get to concerts. And if you haven’t had the chance to hear this band, do go and hear them – they’re terrific!

At the end of the gig, as an added bonus, the members of the band appeared in the foyer to sign CDs. I had the chance to thank them for the wonderful performance and also now have a signed CD of Songs to the North Sky.

United for Europe 

Posted in Uncategorized on March 25, 2017 by telescoper

Well, as promised, I made it to today’s march in London, despite the best efforts of Late Western Railways.

Apparently the turnout (~100,000) was larger than anticipated so we were much delayed at the start. In fact I was still in Park Lane when the front of the demonstration reached Trafalgar Square.

It was a very pleasant, good-humoured occasion, attended by people of all ages and walks of life. It won’t change the Prime Minister’s decision to activate Article 50 next week, but at least it will remind her that the 48% of the electorate who voted Remain have not gone, and will not go, away.

Here are some pictures I took…

Parliament Square was packed when I arrived so I couldn’t really join the final rally. Instead I went to the spot on Westminster Bridge where a man lost his life on Wednesday and paid my respect. Then I came back to Cardiff.

It’s been a long day, but a very good one. 

March for Europe

Posted in Politics with tags , on March 24, 2017 by telescoper

Just a quick post to say that I’ll be travelling from Cardiff to London first thing tomorrow morning in order to take part in this March to Parliament.

March for Europe

After Wednesday’s terrorist attack near the Palace of Westminster, there has been some talk – some of apparently emanating from BrExit-supporters wanting to sabotage the event – about cancelling this demonstration against the folly of BrExit, and to celebrate the 60th Anniversary of the signing of the Treaty of Rome, but I’m glad to say it is going ahead. I think Wednesday’s events make it even more important that we exercise our democratic rights including the right to engage in peaceful protest. The march goes ahead with the full support of the Police.

For more details please see the facebook page here. I hope this will be a big one!

London looking back

Posted in Biographical with tags , , , on March 23, 2017 by telescoper

I thought I’d do a quick post as a reaction to yesterday’s terrible events in London in which four people lost their lives and several are still critically injured. We now know that the attacker was British and that he was known to the intelligence services. He appears to have acted alone and was armed with knives and drove an ordinary car onto the pavement, hitting a number of people before crashing the car and managing to stab a police officer to death before he was himself shot and killed. Whatever his motivations were, it looks more likely on the basis of information currently available that these were the actions of a crazed individual than part of an international terrorist conspiracy. We should, however, avoid jumping to conclusions and wait for the investigation to be completed.

The first thing I want to do is to express my condolences to the families and friends of those who lost their lives. My thoughts are also with those who were critically injured and I hope with all my heart that they will all recover speedily and completely. Physical healing will take time, but they will need help, support and time  to come to terms with the mental trauma too. The same is true for those who were caught up in this attack and received minor injuries or even just witnessed what happened, because they must have been shocked by the experience. I hope they receive all the help they need at what must be a very difficult time.

The second point is that it’s clear that the police and other emergency services acted with great courage and professionalism yesterday. One policeman sadly died, but the swift actions of his colleagues prevented further loss of life. Ambulances, paramedics and members of the public all responded magnificently to care for those injured, and we shall probably find that their response saved many lives too. They deserve all our thanks.

Finally, I noticed a number of ill-informed comments on Twitter from the usual gang of Far-Right hate-mongers, especially professional troll Katie Hopkins, claiming that London was “cowed” and “afraid” because this attack. I don’t believe that for one minute, and I want to explain why.

I lived in London for about eight years (between 1990 and 1998). During that time I found myself in relatively close proximity to three major bomb explosions, though fortunately I wasn’t close enough to be actually harmed. I also concluded that my proximity to these events was purely coincidental…

The first, in 1993, was the Bishopsgate Bombing. I happened to be looking out of the kitchen window of my flat in Bethnal Green when that bomb went off. I had a clear view across Weavers Fields towards the City of London and saw the explosion happen. I heard it too, several seconds later, loud enough to set off the car alarms in the car park beneath my window.

This picture, from the relevant Wikipedia page, shows the devastation of the area affected by the blast.

The other two came in quick succession. First, a large bomb exploded in London Docklands on Friday February 8th 1996, at around 5pm, when our regular weekly Astronomy seminar was just about to finish at Queen Mary College on the Mile End Road. We were only a couple of miles from the blast, but I don’t remember hearing anything and it was only later that I found out what had happened.

Then, on the evening of Sunday 18th February 1996, I was in a fairly long queue trying to get into a night club in Covent Garden when there was a loud bang followed by a tinkling sound caused by pieces of glass falling to the ground. It sounded very close but I was in a narrow street surrounded by tall buildings and it was hard to figure out from which direction the sound had come from. It turned out that someone had accidentally detonated a bomb on a bus in Aldwych, apparently en route to plant it somewhere else (probably King’s Cross). What I remember most about that evening was that it took me a very long time to get home. Several blocks around the site of the explosion were cordoned off. I lived in the East End, on the wrong side of sealed-off area, so I had to find a way around it before heading home. No buses or taxis were to be found so I had to walk all the way. I arrived home in the early hours of the morning.

Anyway, my point is that amid these awful terrorist atrocities of the 1990s, people were not “cowed” or “afraid”. Londoners are made of sterner stuff than that. It is true that one’s immediate response when confronted with, e.g. , a bomb explosion is to be a bit rattled. I’m sure that was true for many Londoners yesterday. That soon gives way to a determination to get on with your life and not let the bastards win. The events of the 1990s gave us a London of road blocks, security barriers and many other irritating inconveniences, but they did not bring the city to a standstill, as some have suggested happened yesterday. For the most part it was “business as usual”.

I don’t live in London anymore, but I think Londoners are as unlikely to be frightened today as they were back then. And it will take much more than one man to “shut down the city”. As a matter of fact, I think only a coward would suggest otherwise.

 

P.S. I forgot to mention another event, in 2005, when I was at the precise location of a bomb explosion but precisely 24 hours early…