Insects, by John Clare

Posted in Literature with tags , , , on July 9, 2019 by telescoper

These tiny loiterers on the barley’s beard,
And happy units of a numerous herd
Of playfellows, the laughing Summer brings,
Mocking the sunshine in their glittering wings,
How merrily they creep, and run, and fly!
No kin they bear to labour’s drudgery,
Smoothing the velvet of the pale hedge-rose;
And where they fly for dinner no one knows–
The dew-drops feed them not–they love the shine
Of noon, whose sun may bring them golden wine.
All day they’re playing in their Sunday dress–
Till night goes sleep, and they can do no less;
Then, to the heath bell’s silken hood they fly,
And like to princes in their slumbers lie,
Secure from night, and dropping dews, and all,
In silken beds and roomy painted hall.
So merrily they spend their summer day,
Now in the cornfields, now the new-mown hay.
One almost fancies that such happy things,
With coloured hoods and richly burnished wings,
Are fairy folk, in splendid masquerade
Disguised, as if of mortal folk afriad,
Keeping their merry pranks a mystery still,
Lest glaring day should do their secrets ill.

by John Clare (1793-1861)

 

 

O Grande Amor – Getz & Gilberto

Posted in Jazz with tags , , , , on July 8, 2019 by telescoper

There was a time in the 1960s when the Bossa Nova seemed to be everywhere and no one person did more to stimulate the growth of this uniquely Brazilian musical form than singer, guitarist and composer João Gilberto, who passed away on Saturday 6th July at the age of 88. It was Gilberto’s collaboration with tenor saxophonist Stan Getz (and, on some tracks, his wife Astrud Gilberto) on the award-winning album Getz/Gilberto that made the Bossa Nova go global, penetrating not only the world of jazz but the much wider cultural sphere including pop and film music. The most famous track from Getz/Gilberto is undoubtedly The Girl From Ipanema which was a smash hit around the globe in 1964, but my own favourite number from that album is this, with lovely playing by Stan Getz and characteristically understated, almost whispered vocal by João Gilberto himself.

Rest in Peace João Gilberto (1931-2019)

Cosmology with the Minimal Spanning Tree

Posted in The Universe and Stuff with tags , , , , , , on July 8, 2019 by telescoper

There’s a nice paper on the arXiv (by Naidoo et al) with the abstract:

The code mentioned at the end can be found here.

The appearance of this paper gives me an excuse to mention that I actually wrote a paper (with Russell Pearson) on the use of the Minimal (or Minimum) Spanning Tree (MST) to analyze galaxy clustering way back in 1995.

Here’s how we described the Minimal Spanning Tree in that old paper:

Strictly speaking , we used the Euclidean Minimum Spanning Tree in which the total length of the lines connecting a set of points in a tree is minimized. In general cases a weight can be assigned to each link that is not necessarily defined simply by the length. Here is visual illustration (which I think we drew by hand!)

You can think of the MST as a sort of pre-processing technique which accentuates linear features in a point process that might otherwise get lost in shot noise. Once one has a tree (pruned and/or separated as necessary) one can then extract various statistical properties in order to quantify the pattern present.

Way back in 1995 there were far fewer datasets available to which to apply this method and it didn’t catch on at the time. Now, with  ever-increasing availability of spectroscopic redshift surveys maybe its time has come at last! I look forward to playing with the Python code in due course!

 

Proper Cricket Update

Posted in Cricket with tags , , on July 7, 2019 by telescoper

Now that the seemingly interminable Round Robin of matches in the ICC World Cup is over, leaving just India, New Zealand, Australia and England to fight on through the Semi-Finals, I thought I’d give a quick update on the state of play in the Proper Cricket, specifically Division 2 of the County Championship.

After their draw last week against Worcestershire, Glamorgan remain unbeaten at the top of the table. Given last season’s performance that’s pretty amazing even if they have played a game more than second-place Lancashire.

Glamorgan aren’t playing in the latest round of matches so I expect Lancashire to go top this week unless they lose their current game (against Northamptonshire) and gain fewer than four bonus points in the process.

Sussex, in third place, got thrashed in their last game, also against Northants, bowled out twice in fewer than eighty overs in total.

Glamorgan’s next game is against Middlesex at Sophia Gardens and then there’s a break in the proper cricket for the Twenty20 slogging matches.

It’s been a good season for Glamorgan so far, and they have a real chance of getting promoted to Division One. Fingers crossed. The big difference has been far more resilient batting, especially in the 2nd innings, but a sensible rotation of the fast bowlers has also helped keep them fresh.

Scientific Challenge

Posted in Uncategorized on July 6, 2019 by telescoper

I’m gradually coming to the conclusion that not everything on social media that purports to be from an expert is necessarily scientifically valid. Shocking, I know.

Here’s an example:

I’m afraid I failed this challenge. Can you do better?

And no it shouldn’t be π21.

It’s LGBT+ STEM Day! #LGBTSTEMDAY

Posted in LGBTQ+ with tags , , on July 5, 2019 by telescoper

So here we are again at LGBT+ STEM Day. This time last year I was giving a talk in Cardiff and in my post about that event I expressed a hope that we might be able to have a similar one in Maynooth this year. Alas that didn’t come to pass, and today I am just having a day off, but in any case I thought I’d express my gratitude to all the individuals and organizations responsible for setting up and supporting this day and send my best wishes to everyone celebrating it wherever you are!

Wolfram Alpha and the Principle of Astrogeometry

Posted in The Universe and Stuff on July 4, 2019 by telescoper

Regular readers of this blog (both of them) may remember the basically tedious and offensive but occasionally (accidentally) hilarious troll who keeps attempting to post comments like this:

I thought you might like to see the result of feeding the expression found in the above rant into Wolfram Alpha:

This is exactly the expression described above but produces nothing like the claimed value of the Hubble constant, and it’s in the wrong units too.

Update for the benefit of the extremely hard of thinking (especially Mr Hine):

π21 ≈ 2.75 × 1010 (dimensionless).

One parsec = 3.086 ×1016 m so one Megaparsec is 3.086 ×1022 m. Hence 2 × `a Mpc’ × c ≈ 2 × 3.086 ×1022 m × 3 × 108 m s-1 ≈ 1.83 × 1031 m2 s-1.

Thus the full expression is obtained by dividing this by the value for π21 obtained above giving a value approximately 6.7× 1020 m2 s-1 as demonstrated by Wolfram Alpha.

The correct value for the Hubble constant is about 2.2 × 10−18 s−1.

 

UPDATE: It’s interesting how the Megaparsec appears in the numerator in Mr Hine’s expression, but magically transfers to the denominator as far as the units are concerned:

ANOTHER UPDATE:

I think I may have cracked it. I believe Mr Hine’s calculation involves using light-years instead of Mpc or SI (for some reason) the calculation is in which case the calculation becomes:

π21 ≈ 2.75 × 1010 (dimensionless) as before

One parsec = 3.26 light years so one Megaparsec is 3.26 ×106 million light years. Hence 2 × `a Mpc’ × c ≈ 2 × 3.26 ×106 m × 3 × 105 m s-1, using c in km/s.

When divided by the value of π21 this gives a number around 71 (I couldn’t be bothered with the extra decimal places).

However, although it is a number around 71 the units are then km/s times light years, not the correct units which are km/s divided by Megapersecs. The fact that the number comes out close to 70 is just a numerical artefact of Mr Hine’s basic misunderstanding of units and dimensions. In other words, it’s gibberish. I know you’ll all be shocked by this revelation, but it’s true.

A Head Again!

Posted in Biographical, Maynooth with tags , on July 4, 2019 by telescoper

Today is Independence Day – on which all joint probabilities P(A,B) can be expressed in the form P(A)P(B) – and by coincidence I received a letter that I’ve been expecting from the President. No, not Michael D. Higgins (nor Donald Trump for that matter) but the President of Maynooth University, Professor Philip Nolan.

Despite it being marked Strictly Private and Confidential I have actually read it, and it says that I have been appointed as Head of the Department of Theoretical Physics at Maynooth University, with effect from 1st September 2019.

The appointment is for three years in the first instance, with the possibility of renewal for another two years `subject to satisfactory performance’. So just the three years then.

The current Head of Department is taking a sabbatical next semester (from September to January) and just this morning we have been interviewing candidates for a temporary to provide teaching cover for his absence. Now we officially begin the handover (including, I suppose, moving offices…).

It’s about three years now since I stepped down as Head of School at the University of Sussex at which point I didn’t imagine I would be stepping up to be Head of Anything again, but to be honest this position has a smaller and much better defined set of responsibilities than the one I used to hold so I’m actually quite looking forward to it.

But first I’m going to take tomorrow off.

Arkle Bar and Restaurant

Posted in Maynooth with tags , , , on July 3, 2019 by telescoper

A colleague of mine recently received this invitation (which I have subtly anonymized) to the official opening of the Arkle Bar & Restaurant in Maynooth. I presume this is named after the famous steeplechaser of the same name who was born up the road from Maynooth in County Meath. Given the equine connection it’s quite disappointing to see the word `horse’ spelt incorrectly on the invitation, though to be honest I’d probably just go for the champagne anyway as I’ve never really been keen on doeuvres.

Work in Progress

Posted in Education, Maynooth with tags , , on July 3, 2019 by telescoper

It was less than a year ago that I posted this photograph of a sign I saw by the Kilcock Road on my way into work in the Science Building at Maynooth University.

It was a planning notice that started the process of constructing extra buildings to accommodate various new teaching and study spaces on campus.

By way of an update, here are a couple of pictures taken near that location this morning that show how things have progressed.

Although I had some experience of this kind of construction project from Sussex days I’m not really au fait with the technicalities. The main work being done so far seems to be preparatory: levelling the ground, laying drains and sewers, adding pipes for communications cables, changing the road layout and so on. They call this `readying work’. There’s no sign of actual buildings going up yet, but that is to be expected. Using modern building techniques construction of the actual edifice can be very rapid once the groundwork is done.

I’m in the building on the right of the photograph with the mechanical digger in it, so I was a bit worried that all this would lead to an intolerable amount of noise but it’s actually not too bad. The main inconvenience is for people with cars, since a road has been closed for this work, but I walk into campus so it doesn’t affect me directly.

When it’s all done the new building should look like this:

The University’s News item about this project can be read here.

I’ll post further updates when there’s more to report!