Author Archive

Voids, Galaxies and Cosmic Acceleration

Posted in The Universe and Stuff with tags , , , , , , on February 4, 2020 by telescoper

Time for a quick plug for a paper by Nadathur et al. that appeared on the arXiv recently with the title Testing low-redshift cosmic acceleration with large-scale structure. Here is the abstract:

You can make it bigger by clicking on the image. You can download a PDF of the entire paper here.

The particularly interesting thing about this result is that it gives strong evidence for models with a cosmological constant (or perhaps some other form of dark energy), in a manner that is independent of the other main cosmological constraints (i.e. the Cosmic Microwave Background or Type 1a Supernovae). This constraint is based on combining properties of void regions (underdensities) with Baryon Acoustic Oscillations (BAOs) to produce constraints that are stronger than those obtained using BAOs on their own. The data used derives largely from the BOSS survey.

As well as this there’s another intriguing result, or rather two results. First is that the the BAO+voids data from redshifts z<2 gives H0 = 72.3 ± 1.9, while, on the other hand adding, BAO information from the Lyman-alpha forest for from z>2 gives a value H0 = 69 \pm 1.2, favouring Planck over Riess. Once again, the `tension’ over the value of the Hubble constant appears to be related to using nearby rather than distant sources.

Irish Election Update

Posted in Politics with tags , , , , on February 3, 2020 by telescoper

I couldn’t resist one more update before Saturday’s General Election because there has been another opinion poll (Irish Times/IPSOS-MRBI), which I’ve added to the previous ones here:

  • Sunday Times/Behaviour & Attitude: FF 32%; FG 20%; SF 19%
  • Irish Times/IPSOS-MRBI: FF 25%; FG 21%; SF 21%
  • BusinessPost/Red C: FF 26%; FG 23%; SF 19%
  • Daily Mail/Ireland Elects: FF 27%; FG 22%; SF 22%
  • Sunday Times/Panelbase: FF 23%; SF 21%; FG 19%
  • Business Post/Red C: FF 24%; SF 24%: FG 21%.
  • Irish Times/IPSOS-MRBI: FF 23%; FG 20%; SF 25%

This last one is the first to put Sinn Féin in the lead, although to be honest the margin of error is 3% again so there’s really no evidence for a significant change on the last poll by the same outfit.

I still find it very hard to predict what kind of Government Ireland will end up with, but it seems even less likely than before that Leo Varadkar will be leading it.

British friends keep asking me whether all this change is a result of Brexit. I have to say that the answer to that is ‘no’ and neither is it driven entirely by thoughts of a United Ireland. The focus of campaigning is largely on domestic political issues, chiefly housing and health. Most people tend to think Varadkar has handled Brexit pretty well, but his party had failed badly in these other areas.

Spring Semester Starts

Posted in Biographical, Education, Maynooth with tags , , , , , , on February 3, 2020 by telescoper

It’s February 3rd 2020, which means that today is two days after Imbolc, a Gaelic festival marking the point halfway between the winter solstice and vernal equinox. The 1st Day of February is also the Feast day of St Brigid of Kildare (c. 451-525), one of Ireland’s patron saints along with Saints Patrick and Colm Cille. One of her miraculous powers was the ability to change water into ale, which perhaps explains her enduring popularity among the Irish.

In Ireland this day is sometimes regarded as the first day of spring, as it is roughly the time when the first spring lambs are born. It corresponds to the Welsh Gŵyl Fair y Canhwyllau and is also known as the `Cross Quarter Day’ or (my favourite) `The Quickening of the Year’.

Today is, appropriately enough in the light of all this, the start of the Spring Semester of teaching at Maynooth University, the third Spring Semester I will have experienced here. The weather has even played along; it has definitely been spring-like. The Campus, whicgh has beenhas been very quiet for the last week or so since the examinations finished, is full of students again.

This Semester, as was the case last year, I am teaching Engineering Mathematics II and Computational Physics I. The former, what you would probably call a `service course’, covers a mixture of things, mainly Linear Algebra but with some other bits thrown in for fun, such as Laplace transforms. Interestingly I find the Mathematical Physics students do not encounter Laplace Transforms in the first year, but perhaps engineers use them more often than physicists do? I think I’ve written only one paper that made use of a Laplace transform. Anyway, I have to start with this topic as the students need some knowledge of it for some other module they’re taking this semester. I reckon six lectures will be enough to give them what they need. That’s two weeks of lectures, there being three lectures a week for this module.

Once again my teaching timetable for this module is quite nice. I have lectures on Monday, Tuesday and Wednesday and then the students have a choice of tutorial (on either Thursday or Friday). That means I can get through a decent amount of material each week before each tutorial. I don’t do the tutorials, by the way: that’s left to one of our PhD students, who gets paid for doing that and correcting the weekly coursework. There are about 50 students on this module, divided into two courses: Electronic Engineering and Robotics and Intelligent Devices. We don’t have Civil or Mechanical or Chemical Engineering, etc at Maynooth, in case you were wondering.

Anyway, my first lecture was this afternoon at 2pm and had a good turnout. It was so sunny outside that we had to close all the blinds. That’s quite an unusual event for a February lecture!

My first Computational Physics lecture is on Thursday, after which it will be back to the Department for some frantic behind-the-scenes activity ahead of the afternoon lab session, which is in a computer room near my office. Students attend one two-hour lab session in addition to the lecture, on either Thursday or Tuesday. The first lecture being on Thursday the first lab session will be Thursday afternoon, with the same material being covered the following Tuesday.

While my teaching duties are the same this year as they were in the corresponding semester last year, there is a significant difference this year in that I am now also Head of Department. Either side of my first lecture I had to attend a meeting of the Faculty Executive for Science & Engineering, a meeting on `Project LEGO’ (which, sadly, did not involve any actual Lego but was instead about the proposed redesign of the University’s website) and a meeting of Academic Council. I have also been trying to sort out tutors and tutorials for the forthcoming Semester: these don’t start until next week so there’s time, but it’s quite a challenge to get everyone sorted out. A few timetable clashes have also come to light. So, in summary, I’m a bit worn out after today and will shortly go home to vegetate.

At least I didn’t have to find time for the regular Monday afternoon Euclid telecon in which I usually participate. There wasn’t one today because the working group of which I am part is actually meeting in person for a few days… in Paris! I couldn’t go because of all the above!

UK and Ireland Trade

Posted in Politics with tags , on February 2, 2020 by telescoper

For reasons that are probably obvious I recently took a look at the latest figures relating to trade between Ireland and the United Kingdom. These were produced by the UK Government but I’ll nevertheless assume they are trustworthy. The latest complete figures are from 2018; the report was published in January this year (2020).

Here are the key points:

  • In 2018, UK exports to Ireland were worth £35.1 billion; imports from Ireland were £21.6 billion, resulting in a trade surplus of £13.5 billion with Ireland.
  • The UK had a surplus with Ireland in both goods and services.
  • Ireland accounted for 5.5% of UK exports and 3.2% of all UK imports.
  • Ireland was the UK’s 5th largest export market and the 10th largest source of imports.
  • The UK has recorded a trade surplus with Ireland every year between 1999 and 2018.

Brexiter logic states that the fact that the EU exports more to the UK than vice versa means that the EU needs the UK more than the UK needs the EU. Applying the same argument to Ireland would imply that the UK needs Ireland more than Ireland needs the UK (if it were correct). The reality is that membership of the single market has been of benefit to the economy of both countries (and the rest of the EU). Trade is not a zero-sum game. While the Single Market has allowed the UK to generate a trading surplus with Ireland, Ireland has found other opportunities elsewhere to more than make up. Contrary to popular myth, the UK now only accounts for a small fraction of goods exports from Ireland.

As the United Kingdom has left the European Union it must now try to negotiate new trading arrangements that will cover trade with remaining member states, including Ireland. No doubt the EU negotiators will be pressed by Ireland to take steps to reduce the imbalance described above. As the UK no longer wants to avail itself of the benefits of Single Market, it seems likely that other EU member states will want to seize the opportunity to boost their trade by filling the gaps.

Since the UK’s trading agreement with the EU (if there ever is one, which is doubtful) will probably not include services, I thought it would be interesting to look at goods: here is a summary of the breakdown of this category of UK exports to Ireland:

`Miscellaneous manufactured articles’, incidentally, means things made out of plastic, etc.

As a relatively recent arrival in Ireland I find these figures quite interesting in light of my own experience of shopping here. I know that consumer goods aren’t representative of all trade so this is just a comment on my own impressions and is not to be taken too seriously.

If you go into a Supermarket in Ireland you will find that fresh vegetables, meat and dairy products are generally all from local sources. There is a wide choice of these items and value for money is generally very good. The same is true for bread and bread-related products. Some fruit is imported from the EU (especially France and The Netherlands, but including some, e.g. apples, from the UK) and some from further afield (e.g. bananas from the Caribbean and Latin America). You will be shocked to learn that bendy bananas are freely available.

Moving to processed foods (including confectionery, canned items, etc) the picture changes quite a bit. There are local Irish brands but they tend to be alongside familiar British ones. There are also items from elsewhere, e.g. from Italy, that I have never seen on sale in the UK. The (smaller) Irish brands of, say, marmalade seem to be a bit dearer than their imported equivalent but are often of better quality.

As an aside I’ll also mention that supermarkets here have a noticeably smaller range of convenience foods (e.g. microwave meals and ready-made sandwiches) than in corresponding outlets in the UK.

I’ve been impressed at the quality and availability of another important staple, wine. There is a better range of French, Spanish and Italian wines in Supervalu in Ireland, especially at the quality end of the spectrum, than in stores of a similar size in the United Kingdom. There is also a good range of wines from Australia, New Zealand, South Africa and Latin America. I haven’t tried Irish wine yet…

In summary, then, it’s perfectly easy to eat and drink well in Ireland without buying any British products. For myself, I have always tried to buy local food products whenever possible to support the Irish economy as best I can.

Elsewhere in the store however you can see a much greater dominance of UK products. This is particularly true of toiletries (including toothpaste, shampoo), pharmaceutical goods, domestic cleaning products and so on. These tend to be dominated by familiar British brands, although they seem to be more expensive here in Ireland than in the UK.

None of the goods mentioned in the previous paragraph are at all perishable so they could in principle be quite easily be imported from further afield. I wonder if we’ll soon start seeing products of this sort starting to appear from elsewhere?

Irish Election Update

Posted in Biographical, Maynooth, Politics with tags , , , , on February 1, 2020 by telescoper

Well. Life goes on, and so does the Irish General Election campaign. A week today I’ll be casting my vote. Sinn Féin seem the most energized by the events of the last week, even to the extent that their posters have been going up around Maynooth. The one above, showing leader Mary Lou McDonald, is on my way into work (the North Campus of Maynooth University is on the other side of the road, beyond the trees).

Since last week’s update there have been other opinion polls (by the Sunday Times/Panel base and Red C), which I’ve added to the previous ones here:

  • Sunday Times/Behaviour & Attitude: FF 32%; FG 20%; SF 19%
  • Irish Times/IPSOS-MRBI: FF 25%; FG 21%; SF 21%
  • BusinessPost/Red C: FF 26%; FG 23%; SF 19%
  • Daily Mail/Ireland Elects: FF 27%; FG 22%; SF 22%
  • Sunday Times/Panelbase: FF 23%; SF 21%; FG 19%
  • Business Post/Red C: FF 24%; SF 24%: FG 21%.

The latest polls (like the others) are based on a small sample (1000) so has a large marging of error (around 3%) and is based on online responses and an uncertain methodology which may create a systematic bias. Those caveats aside, however, they seems to be telling the same story as the others: decline for Fine Gael and a relatively strong showing for Sinn Féin who are up 7% and 5% on the previous Panelbase and Red C numbers, respectively.

I wouldn’t be at all surprised if Sinn Féin end up with a share of the first preference votes around 25%. If that is the case they’ll probably wish they had stood more candidates, which they will probably do next time if they perform strongly in the actual election. They did poorly in the European Elections last year, which probably explains their rather defensive strategy. On the other hand if Fianna Fáil really are polling in the low twenties they may regret standing so many candidates, as their vote may end up splitting so that none reach the quota.

It will be very interesting to see how this all pans out. I find it very hard to predict what kind of Government Ireland will end up with, but I’m willing to bet that Leo Varadkar won’t be leading it.

The Anthem of Europe

Posted in Music, Politics with tags , , , , on January 31, 2020 by telescoper

(I was tempted to put up the version that is currently No. 1 in the UK charts, but I’m afraid I draw the line at André Rieu…)

 

Brexit Day Blues

Posted in Biographical, Politics with tags , , , on January 31, 2020 by telescoper

Well, here we are then. It’s January 31st 2020. This morning, Facebook reminded me that exactly seven years ago today I left Cardiff University to take up a new job at Sussex University. What a strange 7 years followed! I moved to Sussex, then back to Cardiff, and then here to Maynooth in Ireland. It seems impossible, looking back, that all that happened in just seven years.

Today’s date has a much wider significance, of course. After 11pm (Irish Time) today, the United Kingdom will no longer be a member state of the European Union. Some people seem, for some reason, to think this is a good idea. I don’t, but that’s irrelevant now. It’s happening. And I don’t live in the United Kingdom any more anyway.

It has taken three and a half years since the Brexit referendum for the UK to leave. I’ve heard it said that’s been too long, but historically it usually takes a lot longer to get the British to leave. Just ask Ireland or India, for example.

Anyway, yesterday I planned how to mark the event, and came up with the following.

Dinner will comprise Irish, Spanish, Greek, Dutch, Danish and French ingredients, with Italian wine and afterwards a glass of (Portuguese) port. That’s not all the EU countries, of course, but it’s the best I could do with the available shopping time!

Musical accompaniment will be provided by Beethoven (courtesy of the RTÉ National Symphony Orchestra live from the National Concert Hall in Dublin on RTÉ Lyric FM). I was hoping to go to the concert, but I left it too late to buy a ticket and it’s sold out!

And at the appointed hour I’ll raise a glass to the EU, to everyone in the UK who is being dragged out of it against their will, to my colleagues in the UK who hate what’s happening as much as I do but haven’t had the opportunity to escape, and to all the EU citizens in the UK who have been treated so shabbily by the British Government.

Living in a country that has chosen to define itself by its contempt for foreigners is not going to be easy, and is certain to get worse when Brexit fails to deliver the `sunlit uplands’ that were promised. There are very good reasons to fear for the future.

I wrote back in 2017, when it seemed that the madness of Brexit might still be halted, but I’d decided to leave Britain anyway:

The damage has already been done. The referendum campaign, followed by the callous and contemptuous attitude of the current UK Government towards EU nationals living in Britain, unleashed a sickening level of xenophobia that has made me feel like a stranger in my own country. Not everyone who voted `Leave’ is a bigot, of course, but every bigot voted for Brexit and the bigots are now calling all the shots. There are many on the far right of UK politics who won’t be satisfied until we have ethnic cleansing. Even if Brexit is stopped the genie of intolerance is out of the bottle and I don’t think it well ever be put back. Brexit will also doom the National Health Service and the UK university system, and clear the way for the destruction of workers’ rights and environmental protection. The poor and the sick will suffer, while only the rich swindlers who bought the referendum result will prosper. The country in which I was born, and in which I have lived for the best part of 54 years, is no longer something of which I want to be a part.

The Me of 2020 thinks the Me of 2017 was absolutely right.

I got this today from a friend. Posted on the front door of an EU resident.

An die Freude

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

Freude, Schöner Götterfunken,
Tochter aus Elysium,
Wir betreten feuer-trunken,
Himmlische, dein Heiligtum!
Deine Zauber binden wieder,
Was die Mode streng geteilt;
Alle Menschen werden Brüder,
Wo dein sanfter Flügel weilt.

Wem der grosse Wurf gelungen,
Eines Freundes Freund zu sein,
Wer ein holdes Weib errungen,
Mische seinen Jubel ein!
Ja, wer auch nur eine Seele
Sein nennt auf dem Erdenrund!
Und wer’s nie gekonnt, der stehle
Weinend sich aus diesem Bund!

Freude trinken alle Wesen
An den Brüsten der Natur;
Alle Guten, alle Bösen
Folgen ihrer Rosenspur.
Küsse gab sie uns und Reben,
Einen Freund, geprüft im Tod;
Wollust ward dem Wurm gegeben,
Und der Cherub steht vor Gott.

Froh, wie seine Sonnen fliegen
Durch des Himmels Prächt’gen Plan,
Laufet, Brüder, eure Bahn,
Freudig, wie ein Held zum Siegen.

Seid umschlungen, Millionen!
Diesen Kuss der ganzen Welt!
Brüder über’m Sternenzelt
Muss ein lieber Vater wohnen.
Ihr stürzt nieder, Millionen?
Ahnest du den Schöpfer, Welt?
Such’ ihn über’m Sternenzelt!
Über Sternen muss er wohnen.

by Friedrich Schiller (as revised by Ludwig van Beethoven)

 

On the Surface of the Sun

Posted in The Universe and Stuff with tags , , , on January 30, 2020 by telescoper

There are some wonderful images and movies going around from the Daniel K Inouye Solar Telescope which has produced the highest resolution images of the solar surface ever seen.

Here’s a snapshot:

And here’s a movie:

In the above image you can see the granular structure of the Sun’s photosphere. The cells you can see are a manifestation of the large-scale convective motions that transport energy from the Sun’s inner regions to the surface. This energy is created by nuclear reactions in the solar core and it sets up convective motions in the outer layers rather like those in a pan of boiling water set up by heating from below (or perhaps the gentler motions that appearin a lava lamp).

The surface structure looks surprisingly regular but the highly turbulent magnetized plasma is responsible to an extraordinary range of activity, from sunspots, flares and prominences, to the heating of the solar corona and the generation of the solar wind.

 

Taxing Figures

Posted in Bad Statistics, Politics with tags , , , on January 29, 2020 by telescoper

Following the campaign for the forthcoming General Election in Ireland has confirmed (not entirely unexpectedly) that politicians over here are not averse to peddling demonstrable untruths.

One particular example came up in recent televised debate during which Fine Gael leader Leo Varadkar talked about his party’s plans for tax cuts achieved by raising the salary at which workers start paying the higher rate of income tax. Here’s a summary of the proposal from the Irish Times:

Fine Gael wants to increase the threshold at which people hit the higher rate of income tax from €35,300 to €50,000, which it says will be worth €3,000 to the average earner if the policy is fully implemented.

Three thousand (per year) to the average earner! Sounds great!

But let’s look at the figures. There are two tax rates in Ireland. The first part of your income up to a certain amount is taxed at 20% – this is known as the Standard Rate. The remainder of your income is taxed at 40% which is known as the Higher Rate. The cut-off point for the standard rate depends on circumstances, but for a single person it is currently €35,300.

According to official statistics the average salary is €38,893 per year, as has been widely reported. Let’s call that €38,900 for round figures. Note that figure includes overtime and other earnings, not just basic wages.

It’s worth pointing out that in Ireland (as practically everywhere else) the distribution of earnings is very skewed. here is an example showing weekly earnings in Ireland a few years ago to demonstrate the point.

 

This means that there are more people earning less than the average salary (also known as the mean)  than above it. In Ireland over 60% of people earn less than the average.  Using the mean in examples like this* is rather misleading – the median would be less influenced by a few very high salaries –  but let’s continue with it for the sake of argument.

So how much will a person earning €38,900 actually benefit from raising the higher rate tax threshold to €50,000? For clarity I’ll consider this question in isolation from other proposed changes.

Currently such a person pays tax at 40% on the portion of their salary exceeding the threshold which is €38,900 – €35,300 = €3600. Forty per cent of that figure is €1440. If the higher rate threshold is raised above their earnings level this €3600 would instead be taxed at the Standard rate of 20%, which means that €720 would be paid instead of €1440. The net saving is therefore €720 per annum. This is a saving, but it’s nowhere near €3000. Fine Gael’s claim is therefore demonstrably false.

If you look at the way the tax bands work it is clear that a person earning over €50,000 would save an amount which is equivalent to 20% of the difference between €35,300 and €50,000 which is a sum close to €3000, but that only applies to people earning well over the average salary. For anyone earning less than €50,000 the saving is much less.

The untruth lies therefore in the misleading use of the term `average salary’.

Notice furthermore that anyone earning less than the higher rate tax threshold will not benefit in any way from the proposed change, so it favours the better off. That’s not unexpected for Fine Gael. A fairer change (in my view) would involve increasing the higher rate threshold and also the higher rate itself.

All this presupposes of course that you think cutting tax is a good idea at this time. Personally I don’t. Ireland is crying out for greater investment in public services and infrastructure so I think it’s inadvisable to make less money available for these purposes, which is what cutting tax would do.

 

*Another example is provided by the citation numbers for papers in the Open Journal of Astrophysics. The average number of citations for the 12 papers published in 2019 was around 34 but eleven of the twelve had fewer citations than this: the average is dragged up by one paper with >300 citations.