Archive for April, 2020

#PoetryDayIRL: ‘When You Are Old’, by William Butler Yeats

Posted in Poetry with tags , , , on April 30, 2020 by telescoper

One more for Ireland’s National Poetry Day. I couldn’t resist posting one by William Butler Yeats (known to his friends as ‘WB’)

When you are old and grey and full of sleep,
And nodding by the fire, take down this book,
And slowly read, and dream of the soft look
Your eyes had once, and of their shadows deep;

How many loved your moments of glad grace,
And loved your beauty with love false or true,
But one man loved the pilgrim soul in you,
And loved the sorrows of your changing face;

And bending down beside the glowing bars,
Murmur, a little sadly, how Love fled
And paced upon the mountains overhead
And hid his face amid a crowd of stars.

#PoetryDayIRL: ‘Dublin’, by Louis MacNeice

Posted in Poetry with tags , , , , on April 30, 2020 by telescoper

Here is another poem for Ireland’s National Poetry Day. This one is called Dublin and it was written by Louis MacNeice.

Grey brick upon brick,
Declamatory bronze
On sombre pedestals –
O’Connell, Grattan, Moore –
And the brewery tugs and the swans
On the balustraded stream
And the bare bones of a fanlight
Over a hungry door
And the air soft on the cheek
And porter running from the taps
With a head of yellow cream
And Nelson on his pillar
Watching his world collapse.

This never was my town,
I was not born or bred
Nor schooled here and she will not
Have me alive or dead
But yet she holds my mind
With her seedy elegance,
With her gentle veils of rain
And all her ghosts that walk
And all that hide behind
Her Georgian facades –
The catcalls and the pain,
The glamour of her squalor,
The bravado of her talk.

The lights jig in the river
With a concertina movement
And the sun comes up in the morning
Like barley-sugar on the water
And the mist on the Wicklow hills
Is close, as close
As the peasantry were to the landlord,
As the Irish to the Anglo-Irish,
As the killer is close one moment
To the man he kills,
Or as the moment itself
Is close to the next moment.

She is not an Irish town
And she is not English,
Historic with guns and vermin
And the cold renown
Of a fragment of Church latin,
Of an oratorical phrase.
But oh the days are soft,
Soft enough to forget
The lesson better learnt,
The bullet on the wet
Streets, the crooked deal,
The steel behind the laugh,
The Four Courts burnt.

Fort of the Dane,
Garrison of the Saxon,
Augustan capital
Of a Gaelic nation,
Appropriating all
The alien brought,
You give me time for thought
And by a juggler’s trick
You poise the toppling hour –
O greyness run to flower,
Grey stone, grey water,
And brick upon grey brick.

#PoetryDayIRL: ‘Quarantine’, by Eavan Boland

Posted in History, Poetry with tags , , on April 30, 2020 by telescoper

It is a remarkable fact that when the poet Eavan Boland passed away a couple of days ago, the sad news of her passing led the main TV bulletin here in Ireland. I struggle to think of another country where the death of a poet would be deemed so important.

Anyway, today is National Poetry Day in Ireland so I decided to post a poem by Eavan Boland as a tribute on this day. This is Quarantine a moving contemplation of the tragedy of the Great Hunger.

In the worst hour of the worst season
of the worst year of a whole people
a man set out from the workhouse with his wife.
He was walking — they were both walking — north.

She was sick with famine fever and could not keep up.
He lifted her and put her on his back.
He walked like that west and west and north.
Until at nightfall under freezing stars they arrived.

In the morning they were both found dead.
Of cold. Of hunger. Of the toxins of a whole history.
But her feet were held against his breastbone.
The last heat of his flesh was his last gift to her.

Let no love poem ever come to this threshold.
There is no place here for the inexact
praise of the easy graces and sensuality of the body.
There is only time for this merciless inventory:

Their death together in the winter of 1847.
Also what they suffered. How they lived.
And what there is between a man and woman.
And in which darkness it can best be proved.

The ‘Great Debate’ of 1920 – Shapley vs Curtis

Posted in History, The Universe and Stuff with tags , , , , , on April 29, 2020 by telescoper

I was so busy at the weekend that although I had the date in my diary I forgot to write a post on 26th April, which was the centenary of the Great Debate that took place on 26th April 1920 at the Smithsonian Museum of Natural History.

The principal protagonists on the US debate were astronomers Harlow Shapley and Heber Curtis. It concerned the nature of so-called spiral nebulae (such as the Andromeda Nebula M31 shown above) and the size of the Universe.

Shapley argued the case that distant nebulae were relatively small and lay within the outskirts of Earth’s home galaxy, while Curtis held that they were in fact independent galaxies, implying that they were exceedingly large and distant.

The two scientists first presented independent technical papers about “The Scale of the Universe” during the day and then took part in a joint discussion that evening. Two papers outlining their opposing positions were subsequently published by Shapley and by Curtis in the May 1921 issue of the Bulletin of the National Research Council. The published papers each included counter arguments to the position advocated by the other scientist at the 1920 meeting.

Many at the time felt that Shapley had won the debate, interpretating the Milky Way as the entire Universe rather than just one of many galaxies. The spiral nebulae were relatively nearby, possibly solar systems in the process of formation.

A key piece of evidence in favour of the Shapley argument was provided by Adriaan van Maanen, who claimed to have measured the rotation a spiral nebula which implied the object had to be nearby. Van Maanen’s measurements were later shown to be incorrect. Moreover, within a decade, Edwin Hubble and others had established that the spiral nebulae are in fact large and enormously distant; they galaxies like our own Milky Way.

Two things struck me about this story. One is that it illustrates that its not unusual for a majority scientists to be wrong about something. Debates like this are really not very good for settling scientific arguments. In the end it the data count far more than opinions.

The second is that it is remarkable to think that just a century ago we knew so little about the Universe. Our modern view of the Universe may well turn out to be wrong in some important respects but I still think we can say we know more now than we did then!

I’m reminded of this quote:

We have not succeeded in answering all our problems. The answers we have found only serve to raise a whole set of new questions. In some ways we feel we are as confused as ever, but we believe we are confused on a higher level and about more important things.

New Publication at the Open Journal of Astrophysics!

Posted in Open Access, The Universe and Stuff with tags , , , on April 28, 2020 by telescoper

Well Maynooth University may have been closed by the Coronavirus but the The Open Journal of Astrophysics certainly has not!

In fact we have just published another paper! This one is called Discrete Chi-square Method for Detecting Many Signals and the author is Lauri Jetsu of the University of Helsinki in Finland.

Here is a grab of the overlay as it appears on my phone:

You can find the arXiv version of the paper here.

I’d like to take this opportunity to thank the Editorial team and various referees for their efforts in keeping the Open Journal of Astrophysics going in these difficult times.

Electroacoustic Miniatures (on Astrophysical Themes) – John McClachlan

Posted in Music, The Universe and Stuff with tags , , on April 28, 2020 by telescoper

And now for something completely different.

I was listening to the radio last night – specifically to Bernard Clarke’s Blue of the Night on RTÉ Lyric FM – as a result of which I heard a fascinating piece of music by a composer who is new to me, John McClachlan. The composition I heard was a miniature with an astrophysical theme called Sagittarius A* (the name of the supermassive black hole at the centre of the Milky Way Galaxy) . It turns out that this piece is the first of 12 such miniatures composed during the ‘cultural wave’ of the current Covid-19 lockdown. I gather one is going to played every evening on Blue of the Night for the next few weeks.

All these miniatures are on astrophysical themes, which gives me another excuse for posting them in a playlist here!

One Cigarette – Edwin Morgan

Posted in Poetry with tags , , on April 27, 2020 by telescoper

Today (27th April 2020) is the 100th anniversary of the birth of the late great Scottish poet Edwin Morgan so I thought I’d take the opportunity to post one of my favourite poems of his. This is called One Cigarette:

No smoke without you, my fire.
After you left,
your cigarette glowed on in my ashtray
and sent up a long thread of such quiet grey
I smiled to wonder who would believe its signal
of so much love. One cigarette
in the non-smoker’s tray.
As the last spire
trembles up, a sudden draught
blows it winding into my face.
Is it smell, is it taste?
You are here again, and I am drunk on your tobacco lips.
Out with the light.
Let the smoke lie back in the dark.
Till I hear the very ash
sigh down among the flowers of brass
I’ll breathe, and long past midnight, your last kiss.

by Edwin Morgan (1920-2010)

Coronavirus Confusion

Posted in Covid-19, Uncategorized on April 26, 2020 by telescoper

I’ve been continuing my attempts to keep track of the daily Covid-19 statistics in Ireland over on the page here although it’s getting very confusing with various changes in testing practice, retrospective reclassifications and general complexity of the reporting process.

This cartoon from the latest Private Eye pretty much sums up the situation:

Nevertheless, here is the latest plot

This shows that the progress of the disease is fairly flat but there is no evidence from these data of a significant downward trend in the daily figures.

Here’s a different visualisation in which I plot the daily figures against the cumulative total. You might be interested in this variation in which I plot the daily numbers against the cumulative total. Since this is approximately a graph of the derivative of a function plotted against the function itself, exponential growth would look like a straight line in this figure.

Apart from the (substantial) statistical noise you can see only a slight indication of the curves starting to depart from linearity.

The current restrictions on movement and gatherings are in place until May 5th but on the basis of the figures available to the public I wouldn’t bet against them being extended.

Cosmology Talks: Jurek Bauer on ‘Fuzzy’ Dark Matter

Posted in The Universe and Stuff with tags , , , , , on April 26, 2020 by telescoper

If you are missing your regular seminar experience because of the Coronavirus lockdown, Shaun Hotchkiss has set up a YouTube channel just for you!

The channel features technical talks rather than popular expositions so it won’t be everyone’s cup of tea but for those seriously interested in cosmology at a research level they should prove interesting.

Here’s another example from that series in which Jurek Bauer talks about ‘Fuzzy’ Dark Matter (ie matter in the form of a very light particle such as the axion) and the prospects for constraining its existence using the Square Kilometre Array.

P. S. The paper that accompanies this talk can be found on the arXiv here.

Theoretical Physics at Maynooth University

Posted in Uncategorized on April 25, 2020 by telescoper

As part of our virtual Open Day I made a narrated PowerPoint presentation about Theoretical Physics at Maynooth University.

It’s actually on YouTube so I thought I’d share it here out of general interest.

You can find the Open Day web page for Theoretical Physics here. I think it will stay up for a week or so after the event.