Paul Klee, 1925, oil on cardboard, 38cm by 38cm, Kunstssammlung Basel, Basel.
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Posted in Art on March 31, 2022 by telescoperNew Publication at the Open Journal of Astrophysics
Posted in Open Access, The Universe and Stuff on March 30, 2022 by telescoperIt’s time yet again to announce a new publication in the Open Journal of Astrophysics! This one is the 4th paper in Volume 5 (2022) and the 52nd in all.
The latest publication is entitled A SiPM photon-counting readout system for Ultra-Fast Astronomy and is written by Albert Wai Kit Lau & Yan Yan Chan (of the Hong Kong University of Science and Technology), Mehdi Shafiee (Nazarbayev University, Kazakhstan) and George F. Smoot & Bruce Grossan (Lawrence Berkeley Laboratory).
This paper is in the Instrumentation and Methods for Astrophysics section, and is also the first paper we have published with a Nobel Laureate in the author list!
Here is a screen grab of the overlay which includes the abstract:
You can click on the image to make it larger should you wish to do so. You can find the arXiv version of the paper here.
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Deciphering the past using ancient Irish genomes
Posted in Education, History, Maynooth with tags Daniel Bradley, Genetics, Genomics, ireland, Population Genetics on March 30, 2022 by telescoperI thought I’d use the medium of this blog to advertise the forthcoming Dean’s Lecture at Maynooth University by Prof. Daniel Bradley of Trinity College Dublin which takes place tomorrow evening at 7pm.
The abstract is:
Our genomes are our biological blueprints. Their DNA code also carries the traces of our family ancestry and at a deeper level, the history of the population we come from. With modern instruments we can sequence for the first time the DNA of people who lived thousands of years ago and read their long-lost biological stories. Genomes from ancient Ireland, including from those buried in famous megalithic tombs such as Newgrange and Poulnabrone dolmen, highlight the great migrations that brought different waves of people to the island, and also give us hints of the very different societies that prevailed in our prehistory.
I’ll be attending the lecture in person on Maynooth University campus but it will also be streamed via Youtube so if you find this sort of thing as fascinating as I do but can’t attend in person please do register here in order to get the link that will enable you to join the live stream.
Update: it was very interesting!
Maynooth University Library Cat Update
Posted in Biographical, Maynooth on March 29, 2022 by telescoper
The recent spell of good weather has given Maynooth University Library Cat plenty of opportunities to laze around in the sunshine. I saw him on two occasions yesterday, separated by about 90 minutes, and he didn’t seem to have moved at all in that interval. I suppose he’s conserving energy, no doubt for some nefarious nocturnal purpose.
Unfortunately the weather seems to be about to change, with overnight rain forecast tonight and much colder temperatures from tomorrow. Maybe this will provoke our resident feline to adopt such extreme measures as retreating into his box, or perhaps even moving about occasionally to stay warm.
The Open Journal of Astrophysics – Expanding the Editorial Board
Posted in The Universe and Stuff with tags EM41, RK91, YA59 on March 28, 2022 by telescoperRegular readers of this blog will know that I am Editor-in-Chief of a Diamond open access journal called the Open Journal of Astrophysics. This has been running nicely for a few years now and as the number of submissions ramps up I would like to expand the Editorial Board so the workload on its members and myself (who are all volunteers) does not become too onerous.
We apply a simple criterion to decide whether a paper is on a suitable topic for publication, namely that if it it is suitable for the astro-ph section of the arXiv then it is suitable for the Open Journal of Astrophysics. This section of the arXiv, which is rather broad,is divided thuswise:
- astro-ph.GA – Astrophysics of Galaxies.
Phenomena pertaining to galaxies or the Milky Way. Star clusters, HII regions and planetary nebulae, the interstellar medium, atomic and molecular clouds, dust. Stellar populations. Galactic structure, formation, dynamics. Galactic nuclei, bulges, disks, halo. Active Galactic Nuclei, supermassive black holes, quasars. Gravitational lens systems. The Milky Way and its contents - astro-ph.CO – Cosmology and Nongalactic Astrophysics.
Phenomenology of early universe, cosmic microwave background, cosmological parameters, primordial element abundances, extragalactic distance scale, large-scale structure of the universe. Groups, superclusters, voids, intergalactic medium. Particle astrophysics: dark energy, dark matter, baryogenesis, leptogenesis, inflationary models, reheating, monopoles, WIMPs, cosmic strings, primordial black holes, cosmological gravitational radiation - astro-ph.EP – Earth and Planetary Astrophysics.
Interplanetary medium, planetary physics, planetary astrobiology, extrasolar planets, comets, asteroids, meteorites. Structure and formation of the solar system - astro-ph.HE – High Energy Astrophysical Phenomena.
Cosmic ray production, acceleration, propagation, detection. Gamma ray astronomy and bursts, X-rays, charged particles, supernovae and other explosive phenomena, stellar remnants and accretion systems, jets, microquasars, neutron stars, pulsars, black holes - astro-ph.IM – Instrumentation and Methods for Astrophysics.
Detector and telescope design, experiment proposals. Laboratory Astrophysics. Methods for data analysis, statistical methods. Software, database design - astro-ph.SR – Solar and Stellar Astrophysics.
White dwarfs, brown dwarfs, cataclysmic variables. Star formation and protostellar systems, stellar astrobiology, binary and multiple systems of stars, stellar evolution and structure, coronas. Central stars of planetary nebulae. Helioseismology, solar neutrinos, production and detection of gravitational radiation from stellar systems.
The expertise of the current Editorial Board is concentrated in the area of (2), and a bit of (5), which is where most of our submissions come so we would like to have additional Editors in this area. In addition there are sometimes papers from large collaborations for which existing Editors may be conflicted. We would also like to add some Editors from different areas (i.e. 1, 3, 4 and 6) so this call is open for volunteers from all other areas of astrophysics too, especially stars/exoplanets, etc.
If you’re interested please let me know either by my work email or by using the contact form here:
If you join the Editorial Board we will invite you to an online training session to show you how the platform works.
Thank you in advance for your interest in this project, and I look forward to hearing from you.
Summer Time Again
Posted in History, Maynooth on March 27, 2022 by telescoperWell, Spring has definitely arrived. We’ve had glorious weather for over a week now, exactly as I like it – sunny and not too hot. Yesterday for the first time this year I pegged my washing out on the line in the garden, and of course today the clocks went forward so we’re now on Irish Summer Time.
Among the many sensible decisions made recently by the European Parliament was to approve a directive that will abolish `Daylight Saving Time’. I’ve long felt that the annual ritual of putting the clocks forward in the Spring and back again in the Autumn was a waste of time effort, so I’ll be glad when this silly practice is terminated.
It would be better in my view to stick with a single Mean Time throughout the year. This was supposed to happen in 2021 but I suppose has been delayed because of the pandemic.
The marvellous poster above is from 1916, when British Summer Time was introduced. You might be surprised to learn that the practice of changing clocks backwards and forwards is only about a hundred years old. in the United Kingdom. To be honest I’m also surprised that the practice persists to this day, as I can’t see any real advantage in it. Any institution or organization that really wants to change its working hours in summer can easily do so, but the world of work is far more flexible nowadays than it was a hundred years ago and I think few would feel the need.
Anyway, while I am on about Mean Time, here is a another poster from 1916.
Until October 1916, clocks in Ireland were set to Dublin Mean Time, as defined at Dunsink Observatory, rather than Mean Time as defined at Greenwich. The adoption of GMT in Ireland was driven largely by the fact that the British authorities found that the time difference between Dublin and London had confused telegraphic communications during the Easter Rising earlier in 1916. Its imposition was therefore, at least in part, intended to bring Ireland under closer control of Britain. Needless to say, this did not go down well with Irish nationalists.
Ireland had not moved to Summer Time with Britain in May 1916 because of the Easter Rising. Dublin Mean Time was 25 minutes 21 seconds behind GMT but the change was introduced at the same time as BST ended in the UK, hence the alteration by one hour minus 25 minutes 21 seconds, i.e. 34 minutes and 39 seconds as in the poster.
Geometric Algebra
Posted in Education, Maynooth, The Universe and Stuff with tags Clifford Algebra, Geometric Algebra, Gert Vercleyen, Steve Gull on March 26, 2022 by telescoperYesterday we had a very nice pedagogical seminar in the Department of Theoretical Physics by one of our PhD students, Gert Vercleyen, who talked about something that isn’t really to do with his main research topic. A departmental seminar is a good environment for research students to gain experience giving presentations. Anyway, the abstract for this talk was:
Anyone doing a degree in physics, engineering, or mathematics will, at a very early stage, need to learn how to deal with vectors. Typically the theory of vectors comes with several products, like the dot product which is useful for determining lengths and angles, the cross product which allows one to find orthogonal vectors, and in 2D the complex product which allows one to easily describe rotations and dilations. Each of these products has its benefits and problems. The dot product is not invertible, the complex product only works in 2D, and the cross product has too many issues to put in this abstract. The goal of the talk is to present an alternative product of vectors, the geometric product, that works in any dimension, allows one to get geometric data, and can be used to apply geometric transformations. I will describe how the usual products can be obtained from the geometric product and work out various examples.
I was familiar with the basic ideas of this approach (related to Clifford algebra) which encompasses many ideas used frequently in theoretical physics – including quaternions for example (I have to mention them as I’m in Ireland) – in a single elegant formalism. I have never actually used it for anything however. Maybe that will change, though, as many interesting ideas suggested themselves during the talk.
If you’d like to learn a bit more at an introductory level about Geometric Algebra you could do a lot worse than read this paper which, unbelievably, is almost 30 years old. I mentioned at the end of the talk that the first author of this paper, Steve Gull, taught the first course in Mathematics for Natural Sciences I took when I was in the first year at Cambridge way back in 1982. Although he crammed a huge amount into that course, including the “standard” way of talking about vectors, rotations thereof using matrices, and a bit of cartesian tensors, he didn’t talk about Geometric Algebra.
I do think however that there is a case for starting in Year 1 with geometric algebra instead of the way we do it nowadays, not least because as well as being an elegant formalism it lends itself very easily to computational implementation; indeed, I note that there is a Python implementation of Clifford Algebra (which I have not yet played with). Also I think it’s harder to “unlearn” traditional methods and adapt to new ones as you get older.
Physics in a diverse world…
Posted in Biographical, LGBTQ+, Maynooth with tags arXiv:2203.09485, Diversity, Howard Georgi, Snowmass, Spherical Cow on March 25, 2022 by telescoperRegular observers of the arXiv will have noticed a recent deluge avalanche of papers from the recent Snowmass Community Planning Exercise. There are many excellent reports although they came out all in a flurry which has made it difficult to keep on top of them.
An example that I missed was one that appeared in the Physics Education section of arXiv that arose from a talk by theoretical physicist Howard Georgi given at the KITP Conference: Snowmass Theory Frontier on Feb. 23, 2022. The paper, entitled Physics in a diverse world or A Spherical Cow* Model of Physics Talent, doesn’t have an abstract but is quite short and is well worth reading. You can download it here.
Here is a short extract with which I agree fully the philosophy of which I have tried very hard to follow ever since I got my first Professorship in 1998 (though not always with the cooperation of all colleagues, and sometimes, in the past, against the opposition of a few):
If your career is established and you are not making an explicit and continual effort to encourage, mentor, and support all young physicists, to create a welcoming climate in your department, and to promote the hiring of diverse faculty members, you are part of the problem.
I’m hoping next week to be able to pass on some exciting news in this regard about Maynooth University.
I wrote some of my own thoughts from the point of view of LGBT+ diversity here but much of what I said in that context is of wider relevance.
But that brings us to the question of why we should care about whether LGBT students might be deterred from becoming scientists. This is much the same issue as to why we should worry that there are so few female physics students. The obvious answer is based on notions of fairness: we should do everything we can to ensure that people have equal opportunity to advance their career in whatever direction appeals to them. But I’m painfully aware that there are some people for whom arguments based on fairness simply don’t wash. For them there’s another argument that may work better. As scientists whose goal is – or should be – the advancement of knowledge, the message is that we should strive as hard as possible to recruit the brightest and most creative brains into our subject. That means ensuring that the pool from which we recruit is as large and as diverse as possible. The best student drawn from such a pool is likely to be better than the best student from a smaller and more restricted one.
Big companies haven’t become gay-friendly employers in recent years out of a sudden urge for altruism. They’ve done it because they know that they’d otherwise be discouraging many excellent potential employees from joining them. It’s exactly the same for research
*This is an allusion to the old joke for the tendency of scientists – especially theoretical physicists – to adopt highly simplified models of complex phenomena.
Nice Tutorial Problems
Posted in Education, The Universe and Stuff with tags Electric Field, Electromagnetism, Lorentz Transformation, Magnetic Field, special relativity on March 24, 2022 by telescoperBack to the day job, teaching Advanced Electromagnetism, I put up these two nice tutorial problems about the Lorentz transformation of Electric and Magnetic fields, as a prelude to doing the fully covariant formulation of the Maxwell equations. You might like to have a go at these exercises:
Blog Life
Posted in Biographical, Film, History with tags Operation Carthage, The Shadow of my Eye, The Shell House Raid on March 23, 2022 by telescoperIt has been a very strange past few weeks on the blog with much higher levels of traffic than usual (though it is now reverting to more normal levels). Initially I assumed that this abnormal activity was generated by a certain person sniffing around old posts looking for things to complain about, but further investigation revealed that wasn’t the case at all.
In fact, a large fraction of the increase was generated by a post I wrote about a decade ago about Operation Carthage, a British air raid on March 21st 1945 aimed at destroying the Gestapo Headquarters in Copenhagen.
The reason for the sudden increase in interest in this particular post is that a new film about the tragic events of that day, The Shadow of My Eye, has been on Netflix this month and this has apparently spurred people to google the subject, some of them finding my old post as a consequence. I haven’t seen the film so won’t comment on it myself, although there are some recent comments on the old post from people about it.
Talking about comments, I should remind my readers that I do have a policy which is published on the front page of this site. The statement of this policy includes
Feel free to comment on any of the posts on this blog but comments may be moderated; anonymous comments and any considered by me to be vexatious and/or abusive and/or defamatory will not be accepted.
If people make it necessary for me to ban them from posting comments, then all their previous comments will automatically be moved offline. I don’t take this step very often, but I make no apology for doing so when a person’s behaviour justifies it.
I hope this clarifies the situation.
In the Dark 