Happy Birthday, Quaternions!

Posted in History, mathematics with tags , , , , on October 16, 2019 by telescoper

Sir William Rowan Hamilton (1805-1865)

Today, October 16th, is Hamilton day! It was on this day 176 years ago, in 1843, that  William Rowan Hamilton first wrote down the fundamental result of quaternions. Apparently he was walking from his residence at Dunsink Observatory into Dublin when he had a sudden flash of inspiration  and wrote the result down on the spot, now marked by a plaque:

 

Picture Credit: Brian Dolan

This episode  is commemorated by an annual Hamilton Walk. Sadly,  Broombridge (Droichead Broome) is near the bridge (Broom Bridge) where Hamilton had his Eureka moment and it is on the main commuter line from Maynooth into Dublin. This is ironic because Quaternion algebra does not commute. (Geddit?)

Although it is quite easy to reach Broombridge from Maynooth, I sadly can’t attend the walk this year because I’m teaching this afternoon.

P.S. Maynooth is also home to the Hamilton Institute which promotes and facilitates research links between mathematics and other fields.

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Prestige Bias and Luck

Posted in Uncategorized with tags , , , on October 15, 2019 by telescoper

Quite a few times on this blog I have acknowledged the tremendous amount of luck I have had all the way through my career, not least that the opportunity which led to my current position in Maynooth came up when exactly when it did, but another thing that has played a role has been privilege, defined not only in terms of race and social class but also educational and institutional background. Those of us who have benefitted from this are often blind to its influence, preferring to think we achieve things purely on merit. I was reminded of this by an interesting paper on the arXiv by Brian Skinner, which has the abstract:

One of the major benefits of belonging to a prestigious group is that it affects the way you are viewed by others. Here I use a simple mathematical model to explore the implications of this “prestige bias” when candidates undergo repeated rounds of evaluation. In the model, candidates who are evaluated most highly are admitted to a “prestige class”, and their membership biases future rounds of evaluation in their favor. I use the language of Bayesian inference to describe this bias, and show that it can lead to a runaway effect in which the weight given to the prior expectation associated with a candidate’s class becomes stronger with each round. Most dramatically, the strength of the prestige bias after many rounds undergoes a first-order transition as a function of the precision of the examination on which the evaluation is based.

You can read the full paper here. The author acknowledges the role that blind luck played in his own career but also develops a simple mathematical model of prestige bias. It’s an interesting paper, well worth a read.

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The Bush, by R.S. Thomas

Posted in Poetry with tags , , on October 15, 2019 by telescoper

I know that bush,
Moses; there are many of them
in Wales in the autumn, braziers
where the imagination
warms itself. I have put off
pride and, knowing the ground
holy, lingered to wonder
how it is that I do not burn
and yet am consumed.

And in this country
of failure, the rain
falling out of a black
cloud in gold pieces
there are none to gather,
I have thought often
of the fountain of my people
that played beautifully here
once in the sun’s light
like a tree undressing.

by R.S. Thomas (1913-2000)

 

 

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More Hubble Constant Tension

Posted in The Universe and Stuff with tags , , , on October 14, 2019 by telescoper

Here’s the abstract of another contribution to ongoing discussions around so-called tension between different estimates of the Hubble Constantpolldaddy (see this blog passim):

You can find the actual paper (by Lin, Mack and Hou) on the arXiv here.

Now, before Mr Hine starts to fill up my blocked comments folder with rants, I will add a few comments of my own.

First, at the Royal Astronomical Society on Friday I discussed all this with a renowned observational astronomer and expert on stellar distance measurements. He agreed with me that if the `tension’ is indeed real then it is far more likely to be a problem with stellar distance measurements than the cosmology.

Second, I am writing a review of all this to be published in Astronomy & Geophysics next year. Watch this space.

Third, this gives me an excuse to include yet again my poll on whether you are worried about the “tension”:

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Dinner with Wagner

Posted in History, Opera with tags , , , on October 13, 2019 by telescoper

Before dinner with the RAS Club on Friday evening I was looking through the display cabinets at the Athenaeum and saw this, the record of a dinner involving a member and guests on 23rd May 1877. The member was electrical engineer, businessman and Fellow of the Royal Society Carl Wilhelm Siemens and among is guests was Richard Wagner:

Dinner started early and was evidently a lengthy affair, much like Wagner’s operas!

That reminds me of a famous review of one of Wagner’s operas by a critic who clearly wasn’t a fan.

Parsifal is an Opera by Richard Wagner that starts at half past five. Three hours later, you look at your watch and it’s quarter to six.

P.S. There is a photograph taken of Wagner (whose 64th birthday was on 22nd May) during his visit to London in 1877:

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Antony Gormley at the Royal Academy

Posted in Art with tags , , on October 11, 2019 by telescoper

One of the nice things about the location of premises of the Royal Astronomical Society in Burlington House is that it’s right next to the Royal Academy. I took advantage of this proximity yesterday to have a look at the exhibition of work by Antony Gormley. The Main Gallery was very busy as I did my tour but I spent a very enjoyable time wandering around the various rooms and, in some cases, inside the installations therein.

The Royal Academy is a very traditional gallery space and it was the ingenious use of that space within the formal confines of the gallery that I found most impressive. In some of the rooms thin steel bars run through and out from the doors like beam of laser light. Two such beams arrive in one room where they are joined by a vertical bar of the same type, setting up coordinate axes for the whole show.

Here are some snaps I took on the way around:

Clearing

Matrix

Lost Horizon

Cave

Host

`Cave’ is a large sculpture in rolled steel that you can go into. Parts of it are very dark; the photograph I took was from inside looking out. `Lost Horizons’ has typical Gormleyesque human figures standing upright, upside-down and horizontally on the floor ceiling and walls, an idea that resonates with the coordinate axes mentioned above, which you encounter just before entering this room.

But one of the most fascinating parts of the exhibition is the large collection of Gormley’s workbooks, which show how he develops his ideas, always with reference both to the form and materials of his sculpture and the space into which they are to be placed.

The exhibition is open until 3rd December 2019. Do catch it if you can!

 

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Diversity, Inclusion, Rain and Brexit

Posted in Biographical, Politics with tags , , , , on October 11, 2019 by telescoper

So here I am in a very rainy London. I arrived yesterday for a meeting of the IOP Diversity and Inclusion Committee, which was an interesting occasion with many new things about to unfold, tempered by a bit of sadness that the wonderful Head of Diversity at the IOP, Jenni Dyer, is leaving shortly to take up a new job. However will we manage?

Anyway, instead of flying back to Ireland last night after the meeting, I stayed in London last night because today there is an ordinary meeting of the Royal Astronomical Society at Burlington House, to be followed by a Club Dinner. I’ll be going home to Ireland tomorrow.

Unfortunately the weather has put a dampener on my plans to spend a bit of time wandering around London because it is raining quite heavily and is forecast to do so for the rest of the day. Still, at least the hotel I’m in has WIFI so I can get a few things done this morning before venturing out into the inclement conditions.

Meanwhile the pound is rising against the euro on optimism that there may be a Brexit deal on the horizon after yesterday’s meeting between Boris Johnson and Leo Varadkar. Nobody knows the details but it seems likely that it’s basically the same as Theresa May’s `deal’ except that the `backstop’ is to be replaced by what is effectively a  customs border in the Irish Sea.  My personal preference would be Boris Johnson thrown in the Irish Sea.

I doubt the Democratic Unionists will be happy with this, but Johnson is probably gambling that enough Labour quitlings will vote for it that he no longer needs their support. Of course, that all depends on whether what was discussed yesterday turns into a concrete legally-binding agreement signed off by the EU.

P.S. Bookies’ odds on a No-Deal Brexit on October 31st have drifted out from 4/1 to 5/1.

 

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Peebles Princeton Press Conference

Posted in The Universe and Stuff with tags , , on October 10, 2019 by telescoper

Here I am in the Departure Lounge of Dublin Airport’s Terminal 2 ready for a quick trip to Poundland. To fill in a few minutes before my flight I thought I’d post this video of the press conference held at Princeton University upon the announcement of the award of a Nobel Prize to Jim Peebles. It’s full of interesting things but I particularly liked this quote:

My advice is not to aim for prizes and awards. They will come or they won’t. Don’t judge your career by their number, by the count of prizes. We’re in this for the joy of research, the fascination, the love of science. That is the reward really…

Don’t judge yourself by the awards. Judge yourself by how well you have done, and do your best.

For me that sums up the whole reason for being a physicist. Even those of us who have no chance of winning awards or prizes and whose achievements are at most modest can still feel the joy and the love of science. That is the reward.

 

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Blind Man, Blind Man

Posted in Jazz with tags , , , on October 9, 2019 by telescoper

I heard this on the radio the other night and thought I’d share it here as it’s been a very busy day and I haven’t got the energy to do anything else. It’s from My Point of View the second album Herbie Hancock made for the Blue Note label and was released in 1963. This number is quite reminiscent of the 16-bar blues Watermelon Man, the big hit from his first album but this one has a relaxed soul jazz groove all of its own, backed by straight eights played by the 17-year old drummer Tony Williams and there are nice solos by Grant Green on guitar, Hank Mobley on tenor and Hancock himself on piano.  Donald Byrd plays trumpet on this track, but doesn’t take a solo.

 

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A Nobel Prize for Jim Peebles!

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

I’ve just dashed back in excitement to the office from two hours of mandatory Financial Report Training to write a quick post before my 12 o’clock lecture on Astrophysics & Cosmology because of the news about the award of the 2019 Nobel Prize for Physics.

My recent post was half right in the sense that half this year’s prize goes to Michel Mayor and Didier Queloz for the discovery of an extrasolar planet. I don’t know either of them personally, but heartiest congratulations to both!

My heart lept with joy, however, to see the other half of the prize go to Jim Peebles (above) for his work on theoretical cosmology. Much of the reason for that is that I’ve had the great honour and pleasure to meet Jim many times over the years. He is not only a truly great scientist but also a extremely nice man whose kindness and generosity is universally recognized. He’s not known as `Gentleman Jim’ for nothing!

The other reason for the excitement is that I was completely taken by surprise by the announcement. I had feared that his chance of winning a Nobel Prize had passed – I argued at the time that Jim should have been awarded a share of the 2006 Nobel Prize because without his amazing pioneering theoretical work the importance of the cosmic microwave background for cosmology and the large-scale structure of the Universe would not have been established so rapidly. As an author of the first paper to provide a theoretical interpretation of the signal detected by Penzias and Wilson, Jim was there right at the start of the modern era of cosmology and his subsequent work constructed the foundations of the theory of structure formation through gravitational instability. I was sad that he didn’t get a share in 2006 for this work, but am absolutely delighted that this has been rectified now!

This was one of the first cosmology books I ever bought. It’s an amazing piece of work that has been essential reading for cosmologists for almost 40 years!

Congratulations to Jim!

Now let me think about what to say to my students about this!

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