Archive for February, 2020

Solidarity with the UCU Strike!

Posted in Education, Politics with tags , , on February 20, 2020 by telescoper

So the latest round of strikes by members of the University and College Union (UCU) began today. There will be fourteen days of strikes spread over four weeks between now and 13th March. The cause of the long-running dispute is twofold: (1) the long-running saga of the Universities pension scheme (about which there were strikes in 2018); and (2) over pay, equality, workloads and the ever-increasing casualization of lecturing and other work.

Among the UK institutions to be involved in the industrial action are Cardiff, Sussex and Nottingham where I have worked at various times in the past. Nobody likes going on strike but the UK higher education system is a very poor state right now, and many of my former colleagues feel that they have no alternative. It will be tough out there on the picket lines in the cold weather, and losing 14 days’ pay is no fun either, but that’s what it means to go on strike.

I’m no longer involved in the UK university system so can’t do much directly to support those taking industrial action but thought the least I could do is wear my union badge* for the duration of the strike. The Irish Federation of University Teachers (IFUT) will no doubt be expressing their support for comrades on strike. It’s not as if higher education in Ireland is immune from casualisation and workload issues.

*On reflection, I should have taken the picture a different way…

Evidence for a Spatially Flat Universe?

Posted in The Universe and Stuff with tags , , , , , , on February 19, 2020 by telescoper

Yesterday I saw a paper by George Efstathiou and Steve Gratton on the arXiv with the title The Evidence for a Spatially Flat Universe. The abstract reads:

We revisit the observational constraints on spatial curvature following recent claims that the Planck data favour a closed Universe. We use a new and statistically powerful Planck likelihood to show that the Planck temperature and polarization spectra are consistent with a spatially flat Universe, though because of a geometrical degeneracy cosmic microwave background spectra on their own do not lead to tight constraints on the curvature density parameter ΩK. When combined with other astrophysical data, particularly geometrical measurements of baryon acoustic oscillations, the Universe is constrained to be spatially flat to extremely high precision, with ΩK = 0.0004 ±0.0018 in agreement with the 2018 results of the Planck team. In the context of inflationary cosmology, the observations offer strong support for models of inflation with a large number of e-foldings and disfavour models of incomplete inflation.

You can download a PDF of the paper here. Here is the crucial figure:

This paper is in part a response to a paper I blogged about here and some other related work with the same general thrust. I thought I’d mention the paper here, however, because it contains some interesting comments about the appropriate choice of priors in the problem of inference in reference to cosmological parameters. I feel quite strongly that insufficient thought is given generally about how this should be done, often with nonsensical consequences. It’s quite frustrating to see researchers embracing the conceptual framework of Bayesian inference but then choosing an inappropriate prior. The prior is not an optional extra – it’s one of the key ingredients. This isn’t a problem limited to the inflationary scenarios discussed in the above paper, by the way, it arises in a much wider set of cosmological models. The real cosmological flatness problem is that too many cosmologists use  flat priors everywhere!

 

What’s the Vector, Victor?

Posted in Film, mathematics, The Universe and Stuff with tags , , , on February 18, 2020 by telescoper

Following on from Sunday’s post about the trials and tribulations caused by Storm Dennis, here is a clip of a plane (an Airbus 380)  landing at Heathrow airport on Saturday.

There are other clips of this same event on Youtube and some of them describe this landing as `dangerous’. Although it undoubtedly involved skill and concentration by the pilot it’s not actually dangerous. Aircrew are trained to land in windy weather like this, and it’s fairly routine. My plane to Dublin (an Airbus 320) landed like this on Saturday evening and, although the pilot got a well-deserved round of applause on landing, nobody was ever really at risk.

As it happens, this week I start teaching vector algebra to my first-year Engineering students, so the weekend’s weather events have  given me a good illustration of vector addition. The plane has to have a velocity vector relative to the air such that the sum of it and the wind vector adds to a resultant vector directed along the runway. Lots of people seem to think this is just guesswork but it isn’t. It’s applied mathematics.

This is in principle simple as long as the crosswind is steady, but obviously the pilot needs to be alert to gusting and make adjustments along the way. When the plane has slowed down enough to land in normal conditions, the wind over the wings is still causing a bit of extra lift. You can see that in the last moments before touchdown this aircraft is gliding because of this effect. I’m told that because of this, in windy conditions planes usually descend at a steeper angle than usual.

The interesting bit for me is that the plane touches down in such a way that its body is at an angle to the runway. As soon as it has landed it has to correct this and point along the runway. I think this is done with the rudder rather than the undercarriage, but I don’t know. Perhaps any experienced pilots that happen to be reading this could give more details through the comments box?

P.S. The title of this post is a reference to the film Airplane!

 

Thelonious Monk plays Duke Ellington

Posted in Jazz with tags , , , , on February 17, 2020 by telescoper

This morning there was a reminder on the radio that today is the anniversary of the death of the great Thelonious Monk, who died on 17th February 1982. I went to a concert by British pianist Stan Tracey the day after the sad news broke and he threw away his intended play list and played nothing but Monk tunes for the whole evening. It was a wonderful concert and a moving tribute from one musician to another who had clearly influenced him deeply.

Last week I was asked by a young man to recommend some albums because he wanted to find out more about Monk’s music. Among those I suggested was Thelonious Monk plays Duke Ellington which was recorded in 1956 for the Riverside Label, and features a trio of Thelonious Monk (piano), Oscar Pettiford (bass) and Kenny Clarke (drums).

This is an unusual album because it finds Monk doing what the recording executives asked, namely to play standard tunes rather than his original compositions. The most performed jazz composer of all time* is Duke Ellington so he was a natural source of material to choose, and the album that resulted is absolutely fascinating not least because Monk clearly relates very well to Ellington’s music. In fact it’s one of my all-time favourites. Here is just one track from it, I let a Song go out of my Heart. Enjoy!

*The second most performed jazz composer of all time is none other than Monk himself!

LGBTQ+ STEMinar 2020 – The Conference Photograph!

Posted in Biographical, LGBT with tags , , , on February 17, 2020 by telescoper

Regular readers of this blog – both of them – will be aware that last month I attended the 2020 LGBTQ+ STEMinar at the University of Birmingham. This was fifth of these and the largest one of these do far, with around 250 participants. Anyway, I’ve just received delivery of the conference photo!

You’ll see me on the extreme left about half way up. Of course there are fewer than 250 in the photograph: not everyone wanted to be in it (for a variety of reasons).

Anyway, the next one of these will be in 2021 in Oxford where, I am told, there is also a university.

The Growing Inaccessibility of Science

Posted in Open Access on February 16, 2020 by telescoper

No comment necessary, except to thank Brendan O’Brien for sending this to me via Twitter.

Weekend Weather and Travel Updates

Posted in Biographical, Cardiff with tags , , , on February 16, 2020 by telescoper

I got back from London to Dublin last night, rather later than planned courtesy of Storm Dennis. I made my way to Heathrow more in hope than expectation, as there seemed to be a significant probability that my flight would be cancelled (as several were), but in the end it was only delayed by about an hour. It was a bit wobbly coming in to land, but the weather in Dublin wasn’t all that bad last night so there wasn’t the level of drama I expected. I did miss the last Hopper bus, though, and had to take a taxi to Maynooth.

There was another bit of disruption earlier in the day when I discovered that there were no Piccadilly or District line trains between Hyde Park Corner and Acton Town (in either direction), which makes it impossible to get to Heathrow directly by Tube. That gave me an opportunity to explore the London Underground to find a way through. I had plenty of time so I thought it would be fun. In the end I chose the Central Line to Ealing Broadway then a quick couple of stops on the District Line to Acton Town where there were trains to Mornington Crescent Heathrow Airport.

Dublin is to leeward when bad weather comes in from the Atlantic, so doesn’t get the worst of it. This seems to have been the case for Storm Dennis. Wales hasn’t been so lucky and I’ve spent the morning following messages on social media from friends and former colleagues about flooding along the Rover Taff. At one point there were 85 active flood warnings in Wales:

When I bought my house in Pontcanna I signed up for Flood Alerts, and I got one of them too. Here are some pictures of the area taken this morning:

This grim scene is not far from my house, but it’s not as scary as it looks. The River Taff is flanked by steep embankments as it passes into Cardiff and these provide strong flood defences. There is also a tidal barrage across Cardiff Bay which prevents tidewater coming up the River Taff while floodwater is trying to come down it, which is the usual recipe for a flood. The whole system is designed so that before these are breached, water floods out further North over Pontcanna Fields (a wide flat area that is part of the natural flood plain of the Taff that doesn’t have houses on it). A huge amount of water can be `parked’ in this area until the spate subsides. This happened before when I lived in Cardiff in 2009 and it’s nothing to worry too much about. It’s not good for people wanting to play rugby on the playing fields though!

After the terrible floods of 1979 Cardiff built very strong flood defences, but the same is not true for smaller towns up in the Welsh valleys. It seems that Pontypridd has been particularly badly hit this time. There seems to be no political will to spend money protecting such places, which in my view would be far more worthwhile than building HS2.

This all reminds me of the time when I first moved in to my house in Pontcanna over a decade ago. Late one rainy evening the phone rang and it was an automated flood warning. I responded by doing everything the message told me not to do: I put on my coat and went to the river to see what was happening. It’s only a ten minute walk from my house to the embankment. When I got there, I found a crowd of about a dozen people watching. The river was only about a metre below the level of the embankment as it roared its way down to Cardiff Bay carrying along tree trunks, car tyres and various other items of rubbish. It was quite impressive, but I didn’t watch for long as it was very cold and wet.

I’m told that the worst part of the 1979 flood was not the surface water, but the fact that the drainage system couldn’t cope and sewage backed up into the houses and streets. That must have been horrible as well as causing a serious health hazard.

Update: I heard last night that the level of the Taff on Sunday was 80cm higher than it was during the 1979 floods.

Anyway, I was glad I did get back last night as today I am giving a talk at the Joint Congress of University Astronomical Societies. I’d better get on and write it!

Bethnal Green Memories

Posted in Biographical with tags , on February 15, 2020 by telescoper

In London yesterday for a couple of things, including the RAS Discussion Meeting in the afternoon, but on my way to that I thought I’d wander through the part of London where I lived many years ago, so got off the tube at Bethnal Green and went for a short walk.

Bethnal Green doesn’t seem to have changed very much and the street I used to live in looks very much the same as it did in the 90s. I couldn’t resist taking a quick snap of the front door that leads to my old flat as I walked past. I wonder who lives there now?

So much has happened since then it’s hard to believe I lived here for the best part of 9 years! I feel a complete stranger in London nowadays. The past is a foreign country.

Visiting places you used to live isn’t really a good idea. It’s likely to make you feel a bit strange. There are always ghosts hidden among the memories. Perhaps that’s why I keep having dreams that feature former residences. Only in the dreams those places are never quite the same as they actually were.

I remember having a weekend break in Newcastle with an old friend just after my Father died in 2007. At one point we walked past my old school and went in the grounds to have a look. That experience affected me rather a lot and I still don’t know why. The past is the past and it’s not comfortable when it intrudes on the present.

Yesterday, as I carried on walking towards Whitechapel, I suddenly remembered that when I moved in to that flat my Mam gave my a microwave oven. Thirty years on, I still have it and it still works well. It’s in the house in Cardiff. I suppose I’ll have to throw it away at some point. But not yet.

When I lived in Bethnal Green if I wanted to go into Town I would take the tube from either Bethnal Green on Whitechapel, depending on where exactly I wanted to go. This time I found that Whitechapel tube station was closed for refurbishment, so I had to walk on to Aldgate East.

It’s all a question of angles.

Posted in History, mathematics on February 14, 2020 by telescoper

I couldn’t resist reblogging this fascinating post on the origins of trigonometry by the inestimable Thony Christie..

The Renaissance Mathematicus

Thomas Paine (1736–1809) was an eighteenth-century political radical famous, or perhaps that should be infamous, for two political pamphlets, Common Sense (1776) and Rights of Man (1791) (he also wrote many others) and for being hounded out of England for his political views and taking part in both the French and American Revolutions.

Portrait_of_Thomas_Paine Thomas Paine portrait of Laurent Dabos c. 1792 Source: Wikimedia Commons

So I was more than somewhat surprised when Michael Brooks, author of the excellent The Quantum Astrologer’s Handbook, posted the following excerpt from Paine’s The Age of Reason, praising trigonometry as the soul of science:

EO_QsU2WkAIDGol

My first reaction to this beautiful quote was that he could be describing this blog, as the activities he names, astronomy, navigation, geometry, land surveying make up the core of the writings on here. This is not surprising as Ivor Grattan-Guinness in his single volume survey of the history…

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The Journal of Military History and Defence Studies

Posted in History, Maynooth, Open Access with tags , , , on February 13, 2020 by telescoper

I’ve been a bit busy with Computational Physics lectures and labs today so I couldn’t make it to the launch event of a new online Open Access Journal by Maynooth Academic Publishing, who also publish the Open Journal of Astrophysics. The new publication is the Journal of Military History and Defence Studies and its website is here.

Here is the description of the journal:

The Journal of Military History and Defence Studies is a bi-annual peer-reviewed open access online journal that publishers original research and contributions in military history and defence studies. In addition to publishing work by established authors and scholars, the journal has the particular aim of making available to a wide audience the best work completed by postgraduate students studying within these fields at Maynooth University, the Irish Military College and other similar institutions. The journal also aims to publish special editions that make available original research presented at conferences, research seminars etc. As the title suggests, the journal focuses on military history and defence studies, taking a broad view of these subject areas to include the history of war and of militaries, and also of the impact of these on wider society, in addition to the study of war, strategy, security and military organisation today and into the future.

You will see from the website that, as well as catering for a different discipline, this one has a look and feel that is quite different from that of the Open Journal of Astrophysics , but the ultimate aim of both journals is the same, to make high quality research available free of charge to the largest possible audience.