Revisionist (Thermal) History of the Universe

Posted in Biographical, Cardiff, Education, The Universe and Stuff with tags , , on May 10, 2018 by telescoper

Well, today saw my last teaching session on my Cardiff University module Physics of the Early Universe. It was actually an optional revision lecture, during which I went through questions on last year’s examination paper, some matters arising therefrom and some general tips on `examination technique’. The latter included advice that seems obvious – such as `read the question carefully’ and `check your numerical answers’ – but that surprisingly many students seem not to have heard before or, if they have, choose not to follow!

Anyway, I hope the students who came today found it useful and I hope that they (and indeed everyone else taking examinations over the next few weeks) do themselves proper justice and get the results they need for whatever comes next in their plans.

The Physics of the Early Universe paper is a couple of weeks ago so no doubt I’ll get a few more queries to deal with before then.

I thought I’d give an idea of the stuff I’ve been teaching here by including one of the questions from last year’s paper. I thought this was quite an easy one, actually, but the students seemed to find it tricky while they mostly coped well with the other questions, which I thought were harder. One of the challenges of teaching is that it’s often hard to see what other people find difficult! See what you think. You don’t really need to know much cosmology to do this:

Anyway, today was not only the last teaching session for this particular module – it’s also the last teaching session I’ll ever conduct in the UK university system. Best wishes to whoever it is that teaches this module next year when I’m in Ireland.

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When youthful faith has fled

Posted in Poetry with tags , , , on May 9, 2018 by telescoper

When youthful faith has fled,
PU Of loving take thy leave;
Be constant to the dead –
PUThe dead cannot deceive.

Sweet modest flowers of spring,
PUHow fleet your balmy day!
And man’s brief year can bring
PUNo secondary May.

No earthly burst again
PUOf gladness out of gloom;
Fond hope and vision vain,
PUUngrateful to the tomb!

But ’tis an old belief,
PUThat on some solemn shore,
Beyond the sphere of grief,
PUDear friends will meet once more.

Beyond the sphere of time,
PUAnd sin, and fate’s control,
Serene in changeless prime
PUOf body and of soul.

That creed I fain would keep,
PUThat hope I’ll not forego;
Eternal be the sleep,
PUUnless to waken so.

by John Gibson Lockhart (1794-1854). The last three verses of this poem were adapted by Hubert Parry as No. 4 `There is an old belief’ in his Songs of Farewell.

 

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Celebrating the Sloan Telescope

Posted in The Universe and Stuff with tags , , , , , , , , on May 9, 2018 by telescoper

A little bird tweeted at me this morning that today is the 20th anniversary of first light through the Sloan Telescope (funded by the Alfred P. Sloan Foundation) which has, for the past two decades, been surveying as much of the sky as it can from its location in New Mexico (about 25% altogether): the Sloan Digital Sky Survey is now on its 14th data release.

Here’s a picture of the telescope:

For those of you who want the optical details, the Sloan Telescope is a 2.5-m f/5 modified Ritchey-Chrétien altitude-azimuth telescope located at Apache Point Observatory, in south east New Mexico (Latitude 32° 46′ 49.30″ N, Longitude 105° 49′ 13.50″ W, Elevation 2788m). A 1.08 m secondary mirror and two corrector lenses result in a 3° distortion-free field of view. The telescope is described in detail in a paper by Gunn et al. (2006).

A 2.5m telescope of modest size by the standards of modern astronomical research, but the real assets of the Sloan telescope is a giant mosaic camera, highly efficient instruments and a big investment in the software required to generate and curate the huge data sets it creates. A key feature of SDSS is that its data sets are publicly available and, as such, they have been used in countless studies by a huge fraction of the astronomical community.

The Sloan Digital Sky Survey’s original `legacy’ survey was basically a huge spectroscopic redshift survey, mapping the positions of galaxies and quasars in three dimensions to reveal the `cosmic web’ in unprecedented detail:

As it has been updated and modernised, the Sloan Telescope has been involved in a range of other surveys aimed at uncovering different aspects of the universe around us, including several programmes still ongoing.

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Ticket to Ride

Posted in Biographical, Cardiff on May 8, 2018 by telescoper

Although ostensibly based in Cardiff this week I was today required to attend a meeting in London.

This morning I travelled to London Paddington. Inevitably the train was late. The advertised 10 carriage train also turned out to have only 5 carriages and was crammed; there were no seat reservations.

The meeting I attended was quite productive, and I had a nice walk back to Paddington in the warm sunshine.

Now I’m on the return train which also has only five carriages. It seems like Late Western policy to run trains with a short formation in order to maximise the discomfort of passengers. I do not know yet know if we will arrive on time in Cardiff.

My ticket (a one-day ‘off peak’ travelcard) cost £109.10, roughly the cost of two return flights between Cardiff and Dublin.

As a bonus though I got this:

I’ve always wanted to go there, but I’m not sure I want to visit four times. (For those of you not familiar with British geography, ‘Void’ is a place in the Midlands..)

If anyone thinks the pricing of UK train tickets would be reasonable even if the trains ran on time please explain your reasons via the comments box.

My own view, for what it’s worth, is that the travelling public are being fleeced.

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Stock Photo

Posted in Uncategorized on May 7, 2018 by telescoper

I’m too busy cooking today to do a proper blog so I’ve resorted to posting this stock photo.

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A Day of Sports in Cardiff

Posted in Cardiff, Cricket, Football with tags , , on May 6, 2018 by telescoper

Today I saw my first day of County Cricket this season at Sophia Gardens. It was actually the 3rd day of Glamorgan against Kent, which also turned out to be the last, as Kent won by six wickets.

Defeat for Glamorgan looked pretty inevitable after a horrendous first innings batting collapse from 57-0 to 94 all out. Although they dismissed Kent for 174 and scored 274 in their second innings, the lead of 194 never looked like being enough. On the other hand Yorkshire won their latest match against Essex despite being all out for 50 in their first innings!

As it turned out, in the warm sunshine and good batting conditions, Glamorgan’s bowlers tried hard but didn’t have much luck and never really looked like precipitating the sort of collapse that they needed to win the game.

Today’s play began with a farcical delay caused by a leak in the underground drainage system beneath the square which caused a wet patch. Play was delayed until 12.40 and the players had an early lunch while the sun did its work drying out the square. I’m not sure how this happened but it didn’t affect the game, which was always going to finish today given that there was no chance of the weather intervening. .

A very disappointing result for Glamorgan, but hopefully they can rebound in their next game.

Anyway, just before 2.30pm those of us inside Sophia Gardens (only abiut 250) could hear the sound of fireworks from the Cardiff City Stadium (which is about 20 minutes walk away). Despite only drawing today’s match against Reading, Cardiff City are promoted to the Premiership for next season in second place. They have Birmingham City to thank for that, who beat Fulham 3-1 to secure their Championship survival and prevent Fulham from finishing ahead of Cardiff. Miss Lemon will be pleased.

At the other end of the table, Barnsley, Burton Albion join already relegated Sunderland in League One. The three relegated clubs, once again, are all from the Midlands. It’s strange how often that happens..

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Out Thinkers Dublin

Posted in LGBTQ+, Maynooth on May 5, 2018 by telescoper

I’m back in sunny Cardiff and have quite a lot to do today, so I’ll just do a quick post to say that yesterday I left work in Maynooth slightly earlier than usual to take the train onto Dublin for an event called ‘Out Thinkers’ at the Science Gallery in Dublin. I got there in good time before the show, which was held in a nice little theatre inside the Science Gallery, which is about 15 minutes walk from Connolly Station.

Out Thinkers serves to showcase the talent of LGBT+ researchers, providing a platform where people can talk about their scientific work while truly being themselves. This Out Thinkers event featured a range speakers talking about their research and experiences as LGBT+ individuals in academia.

It was a very enjoyable event and it was a nice opportunity to see some familiar (and some unfamiliar) faces in a new setting.

Sadly, because the event overran a but I had to leave before the finish to get a train back to Maynooth so I didn’t get the chance to say goodbye and thanks to the organisers for the splendid show!

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Rhythm of the Forest – Paul Klee

Posted in Art with tags , on May 4, 2018 by telescoper

Detail from Rhythm of the Forest by Paul Klee (1914), watercolor on ecru cotton coated with plaster, 17cm ×20cm (Musée d’Art et Histoire, Geneva).

 

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End of Term Thoughts

Posted in Biographical, Finance with tags , , , on May 4, 2018 by telescoper

Today is the last day of teaching term at Maynooth University. My last lecture, a revision lecture, was yesterday morning and I spent most of the afternoon helping students put the finishing touches on their project work, which is due in on Tuesday next week. Next Monday is a bank holiday in Ireland (as it is in the UK), then there’s a short period of private study before the examinations start next Friday. As it happens, the theory paper for the module I’ve been teaching on Computational Physics is on the first day of the examination period.

It’s `Study Week’ in Cardiff next week too, and I have a revision lecture there. Owing to the Monday holiday we’ve juggled the schedule a bit to ensure all modules have a revision lecture so I’m doing my revision lecture on Thursday rather than the usual Tuesday. I have a meeting at the Institute of Physics in London on Tuesday and it’s the Annual General Meeting of the Royal Astronomical Society (also in London) on Friday so I’ll be spending all of next week in the UK, in between Cardiff and London. Since teaching is over I’m not planning any more midweek travel (unless it’s absolutely necessary) and intend to spend one week in the UK and one week in Ireland, and so on, apart from conferences and the like, until I fully relocate in July.

I thought I’d mention another thing, which represents a fortuitous bit of timing. Twenty-five years ago, while I was living in London, I took out a savings policy of the sort that involves making a regular monthly payment into a mixture of investment funds. The term of this policy was 25 years, and the maturity date was 23rd April 2018. On a couple of occasions I have been tempted to cash it in early but decided to let it run until maturity. The performance of my chosen funds has fluctuated over the last two and a half decades, but when the price of units drops and you invest a fixed cash amount you end up buying more units than when they’re expensive so if they do recover in value you do well. This is called Pound Cost Averaging.

However, when a policy like this reaches the end of its term the amount you get back depends on the value of the units on the day that it matures. Although my policy wasn’t doing at all well a decade ago, it seems my portfolio (more by luck than judgement) has done well over the last ten years, but with the stock market being rather volatile in the early part of this year it’s been a bit of a white knuckle ride recently. Thankfully the last few weeks seem to have been more stable, and although the units are not at an all-time high in terms of value they were not far off that when they were cashed in. aturity value turned out to be about three times the total amount I’ve invested. I received the money on 30th April, and the proceeds will make a significant contribution to the cost of purchasing a house here in Ireland.

The downside of pound cost averaging is that the final sum is paid in pounds to a UK bank account, and with the pound languishing against the euro there’s now a decision to be made about when to transfer it to Ireland..

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Stars Dance to the Music of Parallax

Posted in The Universe and Stuff with tags , , on May 3, 2018 by telescoper

I thought I’d share this cute video from the European Space Agency about the Gaia mission I blogged about last week. It shows the effect of parallax, as measured by Gaia, on the positions of stars on the sky. As the Earth orbits the Sun stars do a dance in the sky; the shift in their position greater for closer stars rather than distant ones. To make the video, parallaxes measured by Gaia have been exaggerated by a factor 100,000 and proper motions have been speeded up by one trillion (1012). The effect is rather hypnotic, and gives a sense of the three-dimensional nature of the distribution of stars. At the end of the video you can see the effect of proper motions too, i.e. the change in position of a star due to its actual motion rather than that of the observer.

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