Archive for January, 2020

Farewell to Spitzer

Posted in The Universe and Stuff with tags , , on January 17, 2020 by telescoper

Just a quick post to advertise the fact that NASA’s Spitzer Space Telescope, which was launched in 2003, is due to be `retired’ at the end of January 2020. Spitzer is an infrared telescope that has done a great number of wonderful things over the past 16 years or so. Here’s a short video giving an overview of the mission.

There will be a live-streamed event next week, on January 22nd 2020, featuring mission members and NASA leadership, at 10am PST (6pm GMT/Irish Time) during which members of the public can ask questions. For more details of this event see here.

Although it’s sad to see the end of one `Great Observatory’, hopefully it would be long before the launch of the James Webb Space Telescope which should be even greater. It certainly has a much bigger budget anyway! JWST is due to be launched in March 2021.

January, by R.S. Thomas

Posted in Poetry with tags , , , on January 16, 2020 by telescoper

The fox drags its wounded belly
Over the snow, the crimson seeds
Of blood burst with a mild explosion,
Soft as excrement, bold as roses.

Over the snow that feels no pity,
Whose white hands can give no healing,
The fox drags its wounded belly.

by R.S. Thomas (1913-2000)

 

My Life in Physical Cosmology – Jim Peebles

Posted in The Universe and Stuff with tags , , , on January 16, 2020 by telescoper

This is very nice, a talk by Nobel Laureate Jim Peebles given at the Oska Klein Centre in Stockholm. Well worth watching if you want to learn about the evolution of the field of physical cosmology over the last 50 years or so.

Election Time in Ireland!

Posted in Maynooth, Politics with tags , , , , on January 15, 2020 by telescoper

Yesterday, in response to a request from the Taioseach Leo Varadkar, the Uachtarán na hÉireann Michael D. Higgins dissolved the 32nd Dáil Éireann. There will be a General Election on 8th February (unusually, on a Saturday) to determine the composition of the 33rd Dáil. So we now have three and a half weeks of electioneering. Sigh.

The previous administration, headed by Mr Varadkar, was a minority Government led by his Fine Gael party supported in a `confidence-and-supply’ arrangement by Fianna Fáil. These two parties have more-or-less alternated in running Ireland since Independence, and both could be characterized as centre-right, Neoliberal parties. Fine Gael MEPs sit with the EPP group in the European Parliament while Fianna Fáil’s sit with RE (formerly ALDE). In terms of UK politics FG is closer to the Conservative Party (though not as far to the right) and FF to the Liberal Democrats. There’s therefore even less of a gap between FG and FF than their closest UK equivalents. Incidentally Fine Gael and Fianna Fáil have their roots in the chaos of the Irish civil war in response to the Anglo-Irish Treaty: FG was pro-Treaty and FF anti-Treaty.

The real question to be answered in this election is whether anything might happen to break the right-wing hegemony that has held sway for so long in the Republic. I would to believe so but, frankly, I doubt it. Despite the Varadkar administration’s abject failures on housing and health (led by two spectacularly useless Ministers), and the fact that these two issues are likely to prove extremely important during the campaigns, I feel the innate conservatism of the Irish electorate will led yet again to another FG/FF combination. One of the worries that comes with that is a continuation of the present chronic underfunding of Irish universities.

I am not sure at this point who I’ll be voting for – I don’t yet know who’s standing in my constituency of Kildare North – but it won’t certainly be either Fianna Fáil or Fine Gael. The strongest left-wing party in Ireland is Sinn Féin and I like many of their progressive policies. My main reservation about voting for them is that I’m not a nationalist. Although I would love to see a United Ireland, I consider myself to be an internationalist and find some of the rhetoric of Irish nationalism very uncomfortable. Nevertheless, I believe it would be good for Ireland to have a strong representation from Sinn Féin in the 33rd Dáil Éireann. Other possible leftish parties include the Green Party, Labour and the Social Democrats.

Incidentally, the voting system for General Elections in Ireland is basically the same as that for the European Parliamentary Elections last year, but with a larger number of constituencies (40 instead of 3). Between them these constituencies elect 159 Teachtaí Dála (TDs) (the equivalent of MPs), an average of about 4 per constituency. There are actually 160 seats, but the Speaker is re-elected automatically. The Single Transferable Vote system is used, meaning that voters have a single ballot paper on which they rank the candidates in order of preference. The candidate with the lowest number of first-preference votes is eliminated and their second preference votes redistributed. Candidates are thus progressively eliminated until the requisite number of TDs is selected.

My constituency is Kildare North which elected 1 Social democrat, 1 Fine Gael and 2 Fianna Fáil TDs last time. This is a primarily rural constituency which is, on the whole, rather affluent, as is reflected in the above result.

Luminosity Evolution in Type 1a Supernovae?

Posted in The Universe and Stuff with tags , , , , on January 14, 2020 by telescoper

Figure 1 of Kang et al.

During this afternoon’s very exciting Meeting of the Faculty of Science and Engineering at Maynooth University I suddenly remembered a paper I became aware of over Christmas but then forgot about. There’s an article here describing the paper that makes some pretty strong claims, which was what alerted me to it. The actual paper, by Kang et al., which has apparently been refereed and accepted for publication by the Astrophysical Journal, can be found on the arXiv here. The abstract reads:

The most direct and strongest evidence for the presence of dark energy is provided by the measurement of galaxy distances using type Ia supernovae (SNe Ia). This result is based on the assumption that the corrected brightness of SN Ia through the empirical standardization would not evolve with look-back time. Recent studies have shown, however, that the standardized brightness of SN Ia is correlated with host morphology, host mass, and local star formation rate, suggesting a possible correlation with stellar population property. In order to understand the origin of these correlations, we have continued our spectroscopic observations to cover most of the reported nearby early-type host galaxies. From high-quality (signal-to-noise ratio ~175) spectra, we obtained the most direct and reliable estimates of population age and metallicity for these host galaxies. We find a significant correlation between SN luminosity (after the standardization) and stellar population age at a 99.5% confidence level. As such, this is the most direct and stringent test ever made for the luminosity evolution of SN Ia. Based on this result, we further show that the previously reported correlations with host morphology, host mass, and local star formation rate are most likely originated from the difference in population age. This indicates that the light-curve fitters used by the SNe Ia community are not quite capable of correcting for the population age effect, which would inevitably cause a serious systematic bias with look-back time. Notably, taken at face values, a significant fraction of the Hubble residual used in the discovery of the dark energy appears to be affected by the luminosity evolution. We argue, therefore, that this systematic bias must be considered in detail in SN cosmology before proceeding to the details of the dark energy.

Of course evidence for significant luminosity evolution of Type Ia supernovae would throw a big spanner in the works involved in using these objects to probe cosmology (specifically dark energy), but having skimmed the paper I’m a bit skeptical about the results, largely because they seem to use only a very small number of supernovae to reach their conclusions and I’m not convinced about selection effects. I have an open mind, though, so I’d be very interested to hear through the comments box the views of any experts in this field.

Maynooth University Library Cat Update

Posted in Maynooth with tags , on January 14, 2020 by telescoper

It’s high time for the first update about the famous Maynooth University Library Cat for 2020. I gave him some breakfast on the way in to work yesterday morning, before Storm Brendan arrived. He scoffed it rapidly, even though I strongly suspect I wasn’t the first person to give him food!

I was a bit worried about said feline before the Christmas break because he had a problem with one of his front legs which gave him a limp. I couldn’t see any cuts or anything but it was clearly causing him some bother. Fortunately he seemed to shake it off and there’s no sign of the limp any more.  You can often tell if a cat is poorly because that’s the one situation when they lose their appetite, and there’s no sign of that! Indeed he was quite skittish yesterday when I said hello.

Although the rain hadn’t arrived with Storm Brendan when I fed him yesterday it was already quite windy.  There’s something about windy weather that makes cats freak out a bit. I don’t know what it is. Perhaps the it’s noise? Cats have very sensitive hearing and maybe the sound of the wind causes a kind of sensory overload? My old cat Columbo used to run around like a mad thing when it was windy outside. It’s not that he was unhappy about it – it just got him very excited.

Anyway, today it’s raining quite heavily so I expect Maynooth University Library Cat is tucked up in his little box or somewhere else that’s cosy.

 

Storm Damage

Posted in Biographical, Maynooth with tags , on January 13, 2020 by telescoper

We’ve had an eventful day in Maynooth so far with the arrival of Storm Brendan in Ireland. It was already rather windy when I set out for work about 9.00 this morning and the storm grew in intensity throughout the morning. We’re quite a long way inland, though, and conditions were nowhere near as wild as coastal areas, especially County Cork, where winds reached 140 km/h in places. Other areas badly affected include Galway, Limerick, Kerry and Donegal.

I was just thinking about taking my lunch break at around 12.30 when all the power went off in the Science Building. I had a quick look around inside the Department to check there weren’t any serious issues (e.g. damage to computers) then ventured outside, where I found the entire campus, both South and North, was affected plus the traffic lights on Kilcock Road.

Since it was a widespread power failure I was a bit worried that it might take some time to fix. This, however, wasn’t the case and as I returned from my scouting expedition I saw power had already been restored to some campus buildings. Power outages have happened before at Maynooth and the usual practice is to power up gradually zone by zone, presumably to avoid any surges. Eventually, about an hour after the original interruption to service, everything came back online.

I had just written the end of that paragraph (at about 3.20pm) when the power went off again. That apparently was a scheduled outage in order to fix a `wider network problem’. The electricity supply was only off for about ten minutes this time. Unfortunately, this second power cut seems to have taken out our internet connections so I had to complete this via a wireless connection. Fortunately, WordPress has an autosave facility so I didn’t lose anything. Now let’s see if we can fix the server…

Another Cosmologist for Maynooth!

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

A few people have contacted me to ask what happened with the research position in cosmology at Maynooth University advertised a few months ago. Well, I am now in a position to provide the answer.

I’m very happy to announce that as of January 2nd 2020, Dr John Regan has joined the staff of the Department of Theoretical Physics, bringing with him an SFI – Royal Society University Research Fellowship (URF) which will fund his research for five years.

Dr John Regan

John’s primary area of research is in trying to understand the formation of black holes in the early Universe and their subsequent growth and evolution. He is interested in trying to determine how the first massive black holes in the Universe formed and the conditions required to form them. The problem is well posed since at early times the Universe was a comparatively simple place compared to the Universe today. Recent observations have indicated that Supermassive Black Holes existed less than 1 billion years after the big bang (the Universe is approximately 14 billion years old). A current open problem in Cosmology is how did black holes form and grow quickly enough in order to become super-massive so early in the Universe?

In answering this question John uses high resolution numerical simulations to study the environments in which the first massive black hole seeds may have formed and then grown to become the super-massive ones we can still observe today.

I’m delighted that John has joined the Department and look forward to many years of fruitful collaborations and discussions. He will be joined by a PDRA and a research student in due course.

You can follow John on Twitter here:

Exam Time

Posted in Education, Maynooth with tags , , , on January 12, 2020 by telescoper

Back in Maynooth into the January examination period, I await the arrival tomorrow of the first batch of examination scripts I have to mark, so I thought I’d do a quick post on the topic of examinations.

First, for readers elsewhere, full-time undergraduate students at Maynooth what is called 60 “credits” in a year, usually split into two semesters of thirty credits each. This is usually split into 5-credit modules with an examination in each module at the end of each semester. Projects, and other continuously-assessed work do not involve a written examination, but the system means that a typical student will have at least 5 written examination papers in January and at least another 5 in May. Each examination is usually of two hours’ duration.

This is very similar to the system in most UK universities that I am aware of except that a full year’s work over there is 120 credits so there’s a conversion factor of 2:1. A 5-credit module in Ireland would be a 10-credit module in the United Kingdom, for example, but otherwise the system is similar.

One big difference between our examinations in Theoretical Physics in Maynooth and those at other institutions I’ve taught at in the UK is that the papers here – at least at a reasonably advanced level, say Years 3 and 4 – offer no choice of questions to be answered.  A typical format for a two-hour paper is that there are two long questions, each of which counts for 50 marks. Elsewhere  one normally finds students have a choice of two or three questions from four or five on the paper.

One  advantage of our system is that it makes it much harder for students to question-spot in the hope that they can get a good grade by only revising a fraction of the syllabus. If they’re well designed, two long questions can cover quite a lot of the syllabus for a module, which they have to in order to test all the learning outcomes. To accomplish this, questions can be split into parts that may be linked to each other to a greater or lesser extent to explore the connections between different ideas, but also sufficiently separate that a student who can’t do one part can still have a go at others. With such a paper, however, it is a  dangerous strategy for a student to focus only on selected parts of the material in order to pass.

As an examiner, the Maynooth style of examination also has the advantage that you don’t have to worry too much if one question turns out to be harder than the others. That can matter if different students attempt different questions, but not if everyone has to do everything.

But it’s not just the number of questions that’s important, it’s the duration. I’ve never felt that it was even remotely sensible for undergraduate physics examinations to be a speed test, which was often the case when I was a student. Why the need for time pressure? It’s better to be correct than to be fast, I think. I always try to set examination questions that could be done inside two hours by a student who knew the material, including plenty of time for checking so that even a student who made a mistake would have time to correct it and get the right answer. If a student does poorly in this style of examination it will be because they haven’t prepared well enough rather than because they weren’t fast enough.

The structure of the Maynooth examinations at more introductory level is rather different, with some choice. In my first year module on Mechanics & Special Relativity, for example, there is a compulsory first question worth 50 marks (split into several pieces) and then the students can pick two out of three shorter questions worth 25 marks each. This is a somewhat gentler approach than with the more advanced papers, partly adopted because we have quite a few students doing the General Science degree who taking Mathematical Physics as one of their 4 first-year subjects but will not be taking it further.

As their examination is not until Wednesday, I’ll have to wait until later this week to find out how my first-years have done. This will be the examination taken at University level for most of my class, so let me take this opportunity to pass on a few quick tips.

  1. Try to get a good night’s sleep before the examination and arrive in plenty of time before the start.
  2. Read the entire paper before starting to answer any questions. In particular, make sure you are aware of any supplementary information, formulae, etc, given in the rubric or at the end.
  3. Start off by tackling the question you are most confident about answering, even if it’s not Question 1. This will help settle any nerves.
  4. Don’t rush! Students often lose marks by making careless errors. Check all your numerical results on your calculator at least twice and – PLEASE – remember to put the units!
  5. Don’t panic! You’re not expected to answer everything perfectly. A first-class mark is anything over 70%, so don’t worry if there are bits you can’t do. If you get stuck on a part of a question, don’t waste too much time on it (especially if it’s just a few marks). Just leave it and move on. You can always come back to it later.

Readers of this blog are welcome to add other tips through the comments box below!

Oh, and good luck to anyone at Maynooth or elsewhere taking examinations in the next few weeks!

 

200 Years of the RAS Club

Posted in History, The Universe and Stuff with tags , , on January 11, 2020 by telescoper

Here I am in Heathrow Terminal 2 waiting for flight back to Dublin. I managed to get to London from Birmingham in time for a special dinner to mark the 200th anniversary of the RAS Club. As I have mentioned in previous posts, according to the brief history published on the RAS website:

The ‘Astronomical Society of London’ was conceived on 12 January 1820 when 14 gentlemen sat down to dinner at the Freemason’s Tavern, in Lincoln’s Inn Fields, London. After an unusually short gestation the new Society was born on 10 March 1820 with the first meeting of the Council and the Society as a whole. An early setback, when Sir Joseph Banks induced the Duke of Somerset to withdraw his agreement to be the first President, was overcome when Sir William Herschel agreed to be the titular first President, though he never actually took the Chair at a meeting.

Since the RAS Club always dines on the second Friday of the month after Ordinary Meetings of the Royal Astronomical Society itself, January 10th was the closest date to that first dinner. As expected for such a special occasion, there was a very big turnout with more than double the usual number of diners (and many more guests than usual). It was very nice to see some people I haven’t seen for ages! The food and wine were excellent and we ended with champagne and a slice of a cake baked and decorated for the occasion. Unfortunately it was so crowded in the Gallery Room that I couldn’t get close enough to take a photo of it before it was whisked away to be cut into slices.

After dinner we had some speeches, including one really brilliant one by my former colleague from Cardiff days, Mike Edmunds who had researched the `14 gentlemen’ who attended that first dinner. I had known previously that Charles Babbage and John Herschel were there but here (thanks to Mike) is a complete list:

Charles Babbage, Esq. M.A. F.R.S. L. & E. No. 5 Devonshire Street Portland Place
Arthur Baily, Esq, Gray’s Inn
Francis Baily, Esq. F.R.S. & L.S. Gray’s Inn
Major Thomas Colby, of the Royal Engineers, LL.D. F.R.S. L. & E. Tower
Henry T. Colebrooke, Esq. F.R.S. & L.S. Albany, Piccadilly
Olinthus G. Gregory, LL.D. Professor of Mathematics Royal Military Academy, Woolwich
Stephen Groombridge, Esq. F.R.S. S.R.A.Nap. Blackheath
J.F.W. Herschel, LL.D. F.R.S. Slough
Patrick Kelly, LL.D. Finsbury Square
Daniel Moore, Esq. F.R.S. S.A. & L.S. Lincoln’s Inn
Rev. William Pearson, LL.D. F.R.S. East Sheen, Surrey
James South, Esq. F.R.S. and L.S. No. 11 Blackman Street Southwark
Charles Stokes, Esq. F.R.S. S.A. & L.S. Gray’s Inn
Peter Slawinski D.P. Proff. University Wilna

P.S. Because I was attending the LGBTQ+ STEMinar I couldn’t get to the ordinary meeting of the Royal Astronomical Society earlier in the day, which was a shame because it was there that the winners of this year’s awards were announced. You can find a full list here. Congratulations to all!