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Domhnach na Fola

Posted in History, Sport with tags , , , , , , , , , , , , on November 21, 2020 by telescoper

In the days before lockdown I would often travel past Croke Park on the train from Maynooth into Dublin Connolly station. It’s a magnificent stadium, with a capacity over 80,000, its stands towering up on all sides of the playing field which is used for major sporting events organized by the Gaelic Athletics Association (GAA), chiefly hurling and gaelic football. It’s located quite close to Drumcondra Station, the last stop before Connolly on the way into Dublin. I’ve never actually been inside the ground, and you can’t see much of the interior from the train because of the stands, but I do hope to see a match there one day.

Croke Park looked very different a hundred years ago today, on November 21st 1920 (which was a Sunday).

Croke Park, looking towards Hill 16, taken on the day of November 21st 1920.

Incidentally, the low hill you can see in the background is Hill 16. There’s a story that this was built up using rubble from buildings destroyed during the 1916 Easter Rising, but this seems to be apocryphal.

Anyway, as you can see, there wasn’t much in the way of buildings around the playing field in those days, and not much to give spectators cover if they were trying to flee from gunfire.

A Gaelic football match between Dublin and Tipperary started in Croke Park at 2.45 pm on November 21st. About ten minutes into the game, armed police (including members of the regular Royal Irish Constabulary, Auxiliaries, and some Black and Tans) suddenly arrived at the southern end of the park, panicking some of the spectators who tried to run away. Without warning the police opened fire on the crowd. The first to die was 11 year old William Robinson who was sitting in a tree outside the ground to get a better view. Overall the firing lasted about 90 seconds. Thirteen people were killed outright and another died of his wounds later. Others were injured either by gunfire or in the crush resulting from the panic.

Among the dead was Tipperary’s star player Michael Hogan, who was shot dead on the playing field as he tried to find cover. Information from post-mortems released many years after the event revealed that most of the victims had been shot in the back.

Michael Hogan, star player and Captain for the Tipperary team at Croke Park on Bloody Sunday. He died that day.

The massacre could have been even worse had the British forces at the other end of the ground, who had an armoured car with a machine gun, shown more restraint. The machine gun was fired above the heads of the people running towards this contingent. They didn’t shoot anyone but they did force the crowd back towards the gunfire from the other end of the ground. Had they opened fire at the crowd there would have been a massacre on the scale of Amritsar, where hundreds died.

Witnesses also said that while the security forces let all the Dublin players go, they lined up the entire Tipperary team against a fence and were preparing to shoot them all when a junior officer intervened and ordered them to be released. Tipperary was perceived to be a hotbed of IRA activity. Michael Hogan was in fact a member of the Irish Volunteers.

So what on Earth had happened to trigger this indiscriminate slaughter, on the day known now as Bloody Sunday (Irish: Domhnach na Fola)

The overall context is the Irish War of Independence which started in 1919 and was largely a guerilla campaign waged in rural areas. There had not been large-scale eruptions of violence in Dublin. That changed on November 21st 1920. That morning, members of the Irish Republican Army under the direction of Michael Collins, had carried out an operation across Dublin intended to eliminate the ability of the British forces to gather intelligence on the IRA. Hit squads entered the homes of known or suspected British intelligence operatives across the town and shot them. Fifteen people were killed that morning, including at least two innocent civilians in the process.

The IRA members responsible for the killings on Sunday morning melted away into the city. Once again the police and security services seemed to be fighting an invisible enemy. However, knowing that there was a football match going on that afternoon, and that at least some of those involved with the GAA had strong Republican leanings and may indeed be active IRA members, they decided to search all the spectators at the match of which there were over 10,000. The hope was, presumably, to find in the crowd at least some of those responsible for the morning’s assassinations. Instructions were given that anyone who ran away when the search operation began should be presumed guilty and shot.

News about the morning’s events had spread through Dublin that morning and it was widely anticipated that the British would carry out reprisal killings, probably in their usual indiscriminate fashion they had employed previously. When armed men arrived in vehicles outside the ground, the instinct of many spectators was therefore to run even before the searching began. Nervous and trigger-happy police deployed in a harebrained plan to make the slaughter inevitable. Nobody has ever been brought to justice for the murders at Croke Park.

Later that day two members of the IRA were caught by the security services, taken to Dublin Castle, beaten and then shot under the pretext that they were trying to escape. These killings brought the death toll past thirty. Bloody Sunday indeed.

The events in Croke Park handed a major propaganda victory to the IRA and also sparked an escalation of the violence. Just a week later, at Kilmichael in County Cork, the IRA ambushed two trucks carrying a total of 18 Auxiliaries, killing 17 of them and leaving the other for dead. On December 11th the British burned down a large part of the city of Cork in retaliation against another attack on their forces. And so it went on into 1921 to the point where the British eventually realized that Ireland had become ungovernable (by them) and a process was started that brought about independence (at least for part of Ireland).

As you can imagine there have been many commemorations of the grim events of a century ago. I watched a very interesting documentary on the TV earlier this week and there have been many articles in the newspapers and elsewhere about it, taking different angles. Those I found the most moving were those that dealt with the memory of the innocent lives lost. One very poignant idea was to stage 14 very short plays around Croke Park about each of the victims.

Here is a sort of trailer, featuring the heartbreaking story of Jane Boyle – the only woman to die on Bloody Sunday. Her death was particularly tragic as she was due to marry her fiancé Daniel Byron the following week. The couple went to mass at St Kevin’s Church on Harrington Street on Sunday morning and proceeded to Croke Park afterwards. When the firing started, they fled. In the scramble for safety, Daniel felt Jane’s hand go limp; she had been shot in the back and died instantly. She was buried later that week in her wedding gown.

Dreams, Planes and Automobiles

Posted in Biographical, Covid-19, Education, Maynooth, The Universe and Stuff with tags , , , , , on November 20, 2020 by telescoper

I’ve blogged before about the strange dreams that I’ve been having during this time of Covid-19 lockdowns, but last night I had a doozy. I’ve recently been doing some examples of Newtonian Mechanics problems for my first-year class: blocks sliding up and down planes attached by pulleys to other blocks by inextensible strings; you know the sort of thing.

Anyway, last night I had a dream in which I was giving a lecture about cars going up and down hills taking particular account of the effects of friction and air resistance. The lecture was in front of a camera and using a portable blackboard and chalk, but all that was set up outside in the middle of a main road with traffic whizzing along either side and in the presence of a strong gusty wind. I had to keep stopping to pick up my notes which had blown away, dodging cars as I went.

It would undoubtedly make for much more exciting lectures if I recorded them in such a situation, but I think I’d be contravening traffic regulations by setting up in the middle of the Straffan Road. On the other hand, I could buy myself a green screen and add all that digitally in post-production…

The End of Arecibo

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

I’ve just heard the news that the famous (and indeed iconic) radio telescope in Puerto Rico known as the Arecibo Observatory is to be decommissioned. The facility was badly damaged by Hurricane Maria in 2017 and it was feared it might close then, but it was saved when an agreement was reached whereby a Consortium led by the University of Central Florida took over its operations.

Unfortunately, in August 2020 an auxiliary cable broke in August and tore a 30-metre diameter hole in the reflector dish and damaged the dome above it. Then, earlier this month, one of the telescope’s main steel cables snapped, causing further damage. It has now been decided that it will be too dangerous and too expensive to repair the telescope. It is to be decommissioned and then dismantled entirely. Presumably the site will be returned to the state it was in before the telescope was built.

This will be sad news for the people who work at Arecibo Observatory and for the local economy in Puerto Rico not to mention the many astronomers who have used the facility over the years. For a time it was the largest radio telescope in the world, its 1000ft diameter dish enabling it to achieve a resolution of about 3.5 arc minutes at 21cm. Even before the Hurricane struck, however, Arecibo had been struggling to find the funds necessary to maintain its operations. Now, almost 60 years after it was built, that struggle is over.

Plan S – are you compliant?

Posted in Open Access with tags , , on November 19, 2020 by telescoper

Those nice people at cOAlition S have produced a new online tool that allows authors to check whether a given academic journal complies with the requirements of Plan S as they apply to a given funder and institution. For information on how ot works see here. For the actual tool (beta version) see here.

Obviously I checked how it applies to the Open Journal of Astrophysics and here’s an example result!

LGBTQ+ STEM Day

Posted in LGBTQ+ with tags , on November 18, 2020 by telescoper

Well, we’re here at LGBTQ+ STEM day. I’ll shortly be giving my zoom talk. I’ll post the slides here afterwards; it’s only fair that those people who are listening to the talk should get to see them first!

Incidentally, you’re probably wondering why this year’s LGBTQ+ STEM Day is today, November 18th, instead of the previous date, July 5th. The answer is that it honours astronomer Frank Kameny who, sixty years ago, brought a case of wrongful discrimination on grounds of sexual orientation to the Supreme Court of the United States of America. He lost his case, but it is an important milestone. Frank Kameny died in 2011, at the age of 86.

About 60 people attended the live session, which is quite a good turnout. Probably some more will watch the recording. My slides, such as they are, can be found here:

An Image for Autumn 2020

Posted in Biographical, Covid-19 on November 17, 2020 by telescoper

If there’s an image that sums up Autumn 2020 for me, this is it:

I can hardly go anywhere these days without seeing the disagreeable sight of a discarded face mask at some point. I wish people would take more care when disposing of these things!

A Remnant Problem

Posted in Cute Problems, The Universe and Stuff with tags , , , on November 16, 2020 by telescoper

 

I haven’t posted any physics problems for a while so here’s  a quickie involving dimensional analysis. You have to assume that the supernova remnant mentioned in the question is roughly spherical, like the one shown above (SNR 0500-67.5):

As usual, answers and comments through the box below please!

Click on the `continue reading’ thing if you would like to see my worked solution:

Continue reading

Covid Questions for Ireland

Posted in Covid-19, Maynooth with tags , , on November 15, 2020 by telescoper

I’ve just done my daily update of Covid-19 numbers here and thought I’d show the latest figure:

There are now 262 data points on these graphs. When I started doing the updates I thought it might carry on for two or three months -i t’s now been almost nine and there’s no end in sight.

As you can see the 7-day average of new cases has been falling steadily since entered the period of Level 5 restrictions that is now about half-way through. That, of course, is good news. The problem is that the rate of decrease is really quite slow. The number of new cases on each day for the last week (including today) were: 270, 270, 362, 395, 482, 456, and 378 (today). That is fairly flat, the steep downward trend of the previous week apparently faltering. As a rough guess I’d say that by the time we come out of the current period of restrictions (at the beginning of December) we’ll probably still be having over a hundred new cases per day.

I think that level is far too high for comfort, but the current government is probably going to find it difficult to resist the political pressure to exit the lockdown in time for Christmas. If that does happen, I can see another lockdown looming in January. My superiors at Maynooth University are talking about having on-campus teaching again next Semester, but I think that’s highly unlikely in the circumstances.

Things are even worse in Northern Ireland where the number of new cases announced today was 478. Daily cases have been running higher there than in the Republic for some time, despite the fact that the six counties of Northern Ireland have a population of just 1.9 million compared to the 4.9 million of the 26 counties  in the Republic.

That brings me to the issue of the Pfizer Covid-19 vaccine that everyone is getting excited about. Assuming that it passes the various tests needed for it to be approved, Ireland would get about 2 million doses from the stock procured by the European Union.  The population of Ireland is about 4.9 million, and each person would require two doses, which means that supply will only enable about 20% of the population to be vaccinated.

(Actually I don’t know whether the 2 million refers to people that can be vaccinated or individual doses, but even if it’s the former that still accounts for only 40% of the population.)

The question then is who should be prioritized? I think we’d all agree that all health care workers should be vaccinated ASAP but that’s only about 25,000 people (source). Who should get the other doses? Most people seem to be assuming that those at highest risk of mortality should be vaccinated, but there’s also a case to be argued that  it should it should be those groups within which the virus is most likely to spread that should get it, which is presumably the otherwise healthy population.

I don’t know the answer, but it will be interesting to see how this all develops. In any case as far as I can see it there’s very little prospect of high levels of population immunity being reached by this time next year. And that’s even if the vaccine is available soon, which is by no means clear will be the case. As a matter of fact I wouldn’t bet against me still having to do daily updates on Covid-19 statistics for most of next year.

 

Diversity in Physics – LGBTQ+ STEMDay

Posted in Biographical, Books, Talks and Reviews, Cardiff, LGBTQ+ with tags , , , , on November 14, 2020 by telescoper

The nice people involved with Physics at Cardiff University, Prism Exeter and the GW4 group generally have organized a (virtual) event to celebrate Diversity and Inclusion for LGBTQ+ STEM Day 2020 which is to take place on November 18th (that’s next Wednesday). I’m very honoured to have been invited to give a keynote talk at this event, the poster for which is below, and am looking forward to it.

There’s a blog post here that gives more information about the event, including how to register in order to receive the Zoom connection.

I won’t be able to stay for the whole event as I am teaching later that day. I’d have been particularly interested in the session on Open Science…

Newton’s Laws in Words

Posted in History, Maynooth, The Universe and Stuff with tags , , , on November 13, 2020 by telescoper

I’ve been teaching my first-year Mathematical Physics students about Newton’s Laws of Motion so decided to record this little video as an aside discussing the history terminology and use of language.

Unfortunately the only microphone I have is the one built into my laptop and it tends to suffer sometimes from a crackle caused (I think) by the fan inside the machine interfering with the mike. I guess the noise appears when the CPU is working hard causing the machine to heat up so the fan works harder. The sound on video recordings I make this low budget way do break up from time to time, which is rather irritating. Obviously I need to buy an external microphone and when I do I might record this again but in the meantime you’ll just have to put up with it breaking up a couple of times!