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 LGBT 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, LGBT 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!

Memories of Philae

Posted in History, The Universe and Stuff with tags , , , on November 12, 2020 by telescoper

It seems that today is the sixth anniversary of the day (November 12th 2014) that the probe Philae, having detached from its parent spacecraft Rosetta, and subsequently landed successfully (ish) on the Comet 67P/Churyumov-Gerasimenko.

I didn’t realise it was so long ago, but who could forget the feeling of intense excitement we felt on that day as Philae approached its objective?