Archive for November, 2019

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Theoretical Physics at Maynooth University Open Days!

Posted in Education, Maynooth with tags , on November 30, 2019 by telescoper

Today, Saturday 30th November 2019, is another Open Day at Maynooth University.

I used to give Open Day talks quite frequently in a previous existence as Head of School of Mathematical and Physical Sciences at the University of Sussex and now I’m at it again, giving talks on behalf of the Department of Theoretical Physics.

If you’re coming along today, please say hello either at the lecture (2.10pm)) or at the stall in the Iontas Building from 10.30 each day where you can chat about the course or anything else vaguely related to Theoretical Physics. There are other stalls, of course, but the Theoretical Physics one is obviously way more interesting than the others!

I might have time to take a few snaps during the day. If I do I’ll post them here. In the meantime here is a summary of my talk:

UPDATE: I didn’t get time to take any pictures because we were busy all morning. The subject talk in the afternoon was absolutely packed out – way more people than I’ve seen at any other open days here at Maynooth – and loads of questions at the end. Very enjoyable but rather exhausting. I think I might head home for a nap!

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Open Day Friday

Posted in Biographical, Maynooth with tags , , , on November 29, 2019 by telescoper

It’s a busy day today in Maynooth with two very important jobs to do. Until lunchtime I’ll be preoccupied with an Open Day here at Maynooth University, the first of this year’s cycle. Here’s the poster advertising them (with dates included):

You’ll see that I have a new role as Poster Boy for Maynooth University, though they have understandably put me at the extreme edge of the poster (bottom right). I’ve got plenty of people helping on the stall in the Iontas Building today but I do have to give a talk to prospective students. There’s another Open Day tomorrow, for which I’ll be on the stall and doing the talk for most of the day.

Here’s a little promotional video:

Today’s  Open Day winds down by 2pm after which my second major task of the day begins. But that’s a secret, at least for the time being.

 

 

 

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R.I.P. Clive James (1939-2019) – Japanese Maple

Posted in Poetry with tags , on November 28, 2019 by telescoper

More sad news arrived yesterday with the announcement of the death at the age of 80 of broadcaster, writer and critic Clive James. Clive James had been gravely ill for some time and had longer than many people to come to terms with his own mortality. In addition to the other things I mentioned above, he was an accomplished poet as he demonstrated in this reflection on his own end in the farewell poem Japanese Maple which he wrote about five years ago:

Your death, near now, is of an easy sort.
So slow a fading out brings no real pain.
Breath growing short
Is just uncomfortable. You feel the drain
Of energy, but thought and sight remain:

Enhanced, in fact. When did you ever see
So much sweet beauty as when fine rain falls
On that small tree
And saturates your brick back garden walls,
So many Amber Rooms and mirror halls?

Ever more lavish as the dusk descends
This glistening illuminates the air.
It never ends.
Whenever the rain comes it will be there,
Beyond my time, but now I take my share.

My daughter’s choice, the maple tree is new.
Come autumn and its leaves will turn to flame.
What I must do
Is live to see that. That will end the game
For me, though life continues all the same:

Filling the double doors to bathe my eyes,
A final flood of colors will live on
As my mind dies,
Burned by my vision of a world that shone
So brightly at the last, and then was gone.

And here is the man himself reading it. It’s very moving to hear him read this verse, his voice recognisable with its Australian accent and characteristic vocal mannerisms, but it is the voice of an invalid, of a dying man, thin and fading.

R.I.P. Clive James (1939-2019)

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R.I.P. Jonathan Miller (1934-2019) – The Piano in Question

Posted in Music, Television with tags , , on November 27, 2019 by telescoper

I was very sad to read just now of the death of writer, humorist, director and polymath Dr Jonathan Miller who has passed away at the age of 85. The papers are already filled with tributes to Jonathan Miller to which I’ll add a personal recollection that made a big impression on me when I was young and which makes me remember Dr Miller with great fondness.

While I was at school I was captivated by the BBC TV series, directed and introduced by Jonathan Miller, called the Body in Question.

This episode, first broadcast in 1978, shows Dr Miller at the piano with Dudley Moore, his old friend from Beyond the Fringe. They’re exploring the mysterious process by which pianists manage to put their fingers on the right keys without apparently consciously thinking about the mechanical operations involved or even looking at the keyboard. Practice seems to program the hands so that the translation from sheet music to sound becomes second nature, but to those without the ability to effect the transformation (like myself), the process still seems almost miraculous.

R.I.P. Jonathan Miller (1934-2019)

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Another easy physics problem…

Posted in Cute Problems, The Universe and Stuff with tags , , , on November 26, 2019 by telescoper

Many moons ago I posted an `easy’ physics problem from the Physics A-level paper I took in 1981. The examination comprised two papers in those days (and a practical exam); one paper had long questions, similar to the questions we set in university examinations these days, and the other consisted of short questions in a multiple-choice format. The question I posted was one of the latter type. I was reminded about it recently because, years on, it appears people are still trying it (and getting it wrong).

Anyway, since I’m teaching similar things to my first-year Mathematical Physics class I thought I’d put up another question from the same paper.

And here is a poll in which you may select your answer:

Comments on or criticisms of the question are welcome through the comments box…

 

 

 

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Solidarity with the UCU Strikers!

Posted in Education with tags , , on November 25, 2019 by telescoper

The anticipated strikes of staff from UK universities have begun: they will last from today (November 25th 2019) until December 4th. The cause of the 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 casualisation of lecturing and other work.

Among the institutions to have voted for strike action are my previous employers in the UK Cardiff, Sussex and Nottingham. It remains to be seen what the impact of these strikes will be, but they could affect a very large number of students. 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 eight days’ pay before Christmas 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 my own union, the Irish Federation of University Teachers (IFUT) has expressed solidarity with UCU members so I thought the least I could do is wear my IFUT badge for the duration of the strike. It’s not as if Ireland is immune from casualisation and workload issues.

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New Publication at the Open Journal of Astrophysics!

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , on November 24, 2019 by telescoper

Yesterday we published another new paper at The Open Journal of Astrophysics. Here is a grab of the overlay:

The authors are Katarina MarKovic (now of JPL in California), Benjamin Bose (of the University of Geneva) and Alkistis Pourtsidou (Queen Mary, University of London).

You can find the accepted version on the arXiv here. This version was accepted after modifications requested by the referee and editor. Because this is an overlay journal the authors have to submit the accepted version to the arXiv (which we then check against the copy submitted to us) before publishing; version 2 on the arXiv is the accepted version.

I’d like to apologize to the authors for a delay in publishing this paper. It was ready to go a couple of weeks ago, but we had some trouble with an extension to the platform provided by Scholastica which was intended to register Digital Object Identifiers automatically and thus speed up the process. Unfortunately we found some bugs in, and other problems with, the new software and in the end have given up and reverted to the old manual registration process. Hopefully Scholastica will be able to offer a working system for DOI registration before too long.

Anyway, you will see that this is one for the `Cosmology and Nongalactic Astrophysics’ folder. We would be happy to get more submissions from other areas, especially Stellar and Planetary astrophysics. Hint! Hint!

P.S. Just a reminder that we now have an Open Journal of Astrophysics Facebook page where you can follow updates from the Journal should you so wish..

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With the Cosmic Web in Mind..

Posted in Astronomy Lookalikes, The Universe and Stuff with tags , , , , , on November 23, 2019 by telescoper

Some time ago I posted one of my Astronomy Look-alikes about the remarkable similarity between the structure of the human brain and that revealed by computer simulations of the large-scale structure of the Universe:

I wonder whether this means that the Cosmic Web is really just all in the mind?

Anyway I just came across an article by Franco Vazza and Alberto Fenetti that takes the comparison between brain cells (among other things) and the Cosmic Web a bit further, including a look at the corresponding power spectra:

The main point to take from this picture is that many naturally occurring patterns have approximately power-law power spectra, at least over a limited range of scales. However, as I have pointed out before on this blog, the power spectrum on its own does not really quantify pattern in any meaningful way. Here for example are two patterns with exactly the same power spectrum:

The point is that the power spectrum does not contain any information about the phase correlations of the Fourier modes, which are important in quantifying localised features. For further discussion of this issue, see here.

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The Theoretical Physics Equipment Store

Posted in Education, The Universe and Stuff with tags , on November 22, 2019 by telescoper

This door, deep in the bowels of the Department of Theoretical Physics at Maynooth University, leads to a cupboard in which we keep all the equipment used in our Theoretical Physics lectures:

The door is not numbered as a security precaution because of the high value of the items contained in the cupboard. This is foolproof measure because it is the only door in the Department without a number on it, and is therefore impossible to identify. It is here that you will find, among other things, some items I used in my first-year Mechanics lectures:

  • a supply of light inelastic string;
  • frictionless pulleys (various sizes);
  • rigid rods of various lengths;
  • a large array of point masses;
  • smooth inclined planes at various angles;
  • a collection of perfectly elastic spheres;
  • bottles containing a variety of incompressible fluids of negligible viscosity;
  • jars of ideal gas.

I’m mindful, however, that we may lack some items that are in regular use in Theoretical Physics departments elsewhere, perhaps for more advanced topics,  so if anyone has ideas for things to be added to this store please suggest them through the comments box so I can ensure that we have them in stock for next semester.

 

 

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Astronomical Archaeology and the 1919 Eclipse Expeditions

Posted in History with tags , , , on November 21, 2019 by telescoper

Regular readers of this blog (Sid and Doris Bonkers) will know that in the past year I’ve written some articles and given some talks this year about the total solar eclipse on May 29 1919 at which an experiment was performed to test Einstein’s theory of general relativity.

I recently found out about another artefact of that expedition which has turned up in Denmark. More specifically it was discovered in the basement under the Niels Bohr Institute building on Juliane Maries Vej in Copenhagen. In the archive that is situated there they found records of astronomical observations that go more than 120 years back in time recorded on thin glass photographic plates. You can read more about these discoveries here.

Anyway, one of the plates that turned up in Copenhagen shows this image:

A copy of one of the Sobral Eclipse plates

This image is a low-resolution version from a high-resolution scan of the plate (kindly sent to me by Johan Fynbo) concerned which I believe to be a contact copy (rather than an original) of one of the plates made by Andrew Crommelin’s team in Sobral in 1919. I know that a number of such copies were made in the aftermath of the experiment and similar plates have turned up in several locations.

If you look carefully you can see a number of dark rings (one of them quite clear because of the contrast with the solar corona).  These rings surround the stars used to measure the gravitational deflection of light by the sun; you can see the others more clearly if you click on the image to make it larger.

I think this plate illustrates one of the difficulties of this measurement: the gravitational deflection is larger for lines of sight close to the Sun, but the corona is likely to be in the way precisely for those same stars.

 

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