A Formula for the New Year
Posted in mathematics on January 4, 2024 by telescoperAn RAS diary at last!
Posted in Biographical with tags Royal Astronomical Society on January 4, 2024 by telescoperIt’s January 4th and my 2024 RAS Diary has at last arrived in Ireland, just a day after I mentioned not having received one this year. According to the customs declaration I see it wasn’t even posted until 22nd December 2023. Why so late?
The diary part of the RAS diary, being I suppose intended for academics, actually runs from October to December the following year. In previous years it has arrived in time to use it for Semester 1 but for the last four years it hasn’t arrived in the post until December at the earliest, meaning that I couldn’t use the first three months in the new diary. I’m actually surprised it got here so quickly given when it was posted.
Anyway, here it is, along with a collection of older ones. It is actually more purple than the blue it appears in the photograph. Notice the change of logo from 2021.




Although many of my colleagues seem not to use them, I like old-fashioned paper diaries. I do run an electronic calendar for work-related events, meetings etc, but I use the paper one to scribble down extra-curricular activities such as concerts and sporting fixtures, as I find the smartphone version of my electronic calendar a bit fiddly.
A Test for Presidential Plagiarism
Posted in Education, Maynooth with tags academic misconduct, Claudine Gay, Harvard University, Plagiarism, Strategic Plan on January 3, 2024 by telescoperI was shocked today to hear the news that Claudine Gay has resigned from her post as President of Harvard University amid allegations of plagiarism.
I think we can all agree that plagiarism is a serious form of misconduct that constitutes a breach of academic integrity and, as such, should be punished wherever it is found. But just how widespread is this kind of unethical behaviour among the leaders of public universities?
Fortunately, I have thought of a simple test to identify Presidential plagiarism, which I encourage academics everywhere to carry out.
One of the documents for which a University President (or Vice Chancellor, or equivalent) is responsible is their institution’s Strategic Plan, which normally carries their Leader’s signature on the front page.
If you work in a University, therefore, all you need to do is run this document through the plagiarism detector Turnitin. This will compare the document with others available on the internet and produce a similarity report indicating how much of it has been copied from elsewhere. If the document is found to have been significantly plagiarized, then your President (or Vice Chancellor, or equivalent) should be forced to resign.
This simple test will probably lead to many so-called leaders being removed from office so, as well as improving academic integrity, it will also save institutions a great deal of money in salary costs. It’s a win-win situation for all (except perhaps for the ex-Presidents).
P.S. Please feel free to copy this idea.
The Time of Perihelion
Posted in The Universe and Stuff with tags orbit, perihelion, Solar System, Winter Solstice on January 3, 2024 by telescoper
Earth’s elliptical orbit viewed at an angle (which makes it look more eccentric than it is – in reality is very nearly circular).
I haven’t received a Royal Astronomical Society diary this year, which I’m sad about as it has been a bit of a tradition, as well as being a useful source of astronomical information. According to other sources, however, today (Wednesday 3rd January 2024) at approximately 00.39 GMT the Earth reached the point on its orbit closest to the Sun, i.e. its perihelion. At this time the distance from the Sun’s centre to Earth’s centre was 147,100,632 km. This year, aphelion (the furthest distance from the Sun) is at 06.06 GMT on July 6th 2023 at which point the centre of the Earth will be 152,099,968 km from the centre of the Sun. You can find a list of times and dates of perihelion and aphelion for future years here.
At perihelion the speed of the Earth in its orbit around the Sun is greater than at aphelion (about 30.287 km/s versus 29.291 km/s). This difference, caused by the Earth’s orbital eccentricity, contributes to the difference between mean time and solar time which, among other things, influences the time of sunrise and sunset at the winter solstice that happened a couple of weeks or so ago.
It surprises me how many people think that the existence of the seasons has something to do with the variation of the Earth’s distance from the Sun as it moves in its orbit in that the closer to the Sun we get the warmer the weather will be. The fact that perihelion occurs in the depth of winter should convince anyone living in the Northern hemisphere that this just can’t be the case, as should the fact that it’s summer in the Southern hemisphere while it is winter in the North.
The real reason for the existence of seasons is the tilt of the Earth’s axis of rotation. I used to do a little demonstration with a torch (flashlight to American readers) to illustrate this when I taught first-year astrophysics. If you shine a torch horizontally at a piece of card it will illuminate a patch of the card. Keep the torch at the same distance but tilt the card and you will see the illuminated patch increase in size. The torch is radiating the same amount of energy but in the second case that energy is spread over a larger area than in the first. This means that the energy per unit area incident on the card is decreases when the card is tilted. It is that which is responsible for winter being colder than summer. In the summer the sun is higher in the sky (on average) than in winter. From this argument you can infer that the winter solstice not the perihelion, is the relevant astronomical indicator of winter.
That is not to say that the shape of the Earth’s orbit has no effect on temperatures. It may, for example, contribute to the summer in the Southern hemisphere being hotter than in the North, although it is not the only effect. The Earth’s surface possesses a significant North-South asymmetry: there is a much larger fraction of ocean in the Southern hemisphere, for example, which could be responsible for moderating any differences in temperature due to insolation. The climate is a non-linear system that involves circulating air and ocean currents that respond in complicated ways and on different timescales not just to insolation but to many other parameters, including atmospheric composition (especially the amount of water vapour).
The dates when Earth reaches the extreme points on its orbit (apsides) are not fixed because of the variations in its orbital eccentricity so, in the short-term, the dates can vary up to 2 days from one year to another. The perihelion distance varies slightly from year to year too; it’s slightly larger this year than last year, for example.
There is however a long-term trend for perihelion to occur later in the year. For example, in 1246, the December Solstice (winter solstice for the Northern Hemisphere) was on the same day as the Earth’s perihelion. Since then, the perihelion and aphelion dates have drifted by an average of one day every 58 years and this trend will continue. This means that by the year 6430 the timing of the perihelion and the March Equinox will coincide, although I hope to have retired by then…
Here’s to a Diamond New Year…
Posted in Open Access with tags Diamond Open Access, Johan Rooryck, Pierre Mounier on January 1, 2024 by telescoperI know it’s New Year’s Day but I am going to start 2024 the way I mean to continue it, i.e. by banging on about Diamond Open Access. In that vein I am delighted to share a link to a discussion document (by Pierre Mounier & Johan Rooryck) that echoes much of what I have been saying on the subject for quite a while (e.g. here). In my view the ratio of talk to action has been far too high in this context, and the good thing about this document is that it makes concrete practical proposals for a global infrastructure that could support the transition to Diamond Open Access worldwide:
The infrastructure will take the shape of a four-level federation, with each level having its own responsibilities to achieve the shared goal of strengthening diamond open access as a leading scholarly communication model. These levels and their responsibilities are presented in this paper, initiating a discussion with diamond OA communities and other stakeholders in the research landscape. We invite you to come forward and join this discussion.
You can read more here.
Here is a nice illustration:
A global system of federated diamond Open Access repositories would enable a truly innovative and equitable ecosystem for scholarly publication and realize the vision of research as a global public good, which is what it should be. I think Ireland is in a good position to play a leading role in this revolution, actually, as there is much going on in this respect (e.g. in the construction of a national peer review platform).
P.S. I think that a federated system of social media for public institutions is the way to go, too.
Happy New Year 2024!
Posted in Biographical with tags New Year's Eve on December 31, 2023 by telescoperAs I prepare to make my New Year’s Eve dinner I realize that, although there are several hours to go here, it’s already 2024 in many parts of the world (including Sydney, Australia). Before I get cooking, therefore, I thought I’d wish all my readers around the world a very Happy New Year!
(You might be wondering why I chose a picture from Sydney to illustrate this post. Well, wait and see…)
Aller Anfang ist heiter, die Schwelle ist der Platz der Erwartung.
Goethe
New Publication at the Open Journal of Astrophysics
Posted in OJAp Papers, The Universe and Stuff with tags arXiv:2309.05696, black holes, Fermat potential, general relativity, Gravitational Lensing, The Open Journal of Astrophysics on December 31, 2023 by telescoperIt’s New Year’s Eve and I just remembered that there was a paper at the Open Journal of Astrophysics site that we published before Christmas but that I haven’t yet announced on here, so for the sake of completeness here it is. It takes us to 50 papers published in 2023.
The paper in question is the 50th and final paper in Volume 6 (2023) and it’s the 115th altogether. This one was actually published on Friday 22nd December 2023 but owing to the vacations we had to wait a bit to get the metadata registered.
The title of this one is “What are the parities of photon-ring images near a black hole?” and is a discussion of the Fermat potential (also known as the arrival-time surface) in the context of gravitational lensing by strong gravitational fields and the implication for image parities thereby produced. This one is actually listed in General Relativity and Quantum Cosmology (gr-qc, on arXiv) but is cross-listed as Cosmology and Non-galactic Astrophysics so is eligible for publication here in the appropriate folder.
The authors are Ashish Kumar Meena (Ben Gurion University of the Negev, Israel) and Prasenjit Saha (University of Zurich, Switzerland).
Here is the overlay of the paper containing the abstract:
You can click on the image of the overlay to make it larger should you wish to do so. You can find the officially accepted version of the paper on the arXiv here.
And that concludes Volume 6 of the Open Journal of Astrophysics. Roll on Volume 7.
Third Covid Booster
Posted in Biographical, Covid-19 with tags Coronavirus, Covid-19, Pfizer/BioNTech on December 30, 2023 by telescoper
Back in October, not long after I arrived in Barcelona, I got an email from the HSE saying that sixty-somethings such as myself should get a seasonal Covid-19 booster shot (and possibly a flu jab too). It is over a year since I had my last booster. The procedural difference this time is that, unlike the mass vaccinations of previous years, the injections are being given at local pharmacies with limited capacity rather than large vaccination centres, so I had to book well ahead to find a time and a place. It wasn’t easy to find a slot, actually, even at two months’ notice, but with a bit of help from a nice lady at the HSE I managed.
And so it came to pass that yesterday I had my third booster shot (Pfizer), which means I’ve had five injections in all. Apart from the usual slight numbness in my left arm, I had no after side affects. I’m glad I managed to get the booster, as a large number of people I know have either got Covid-19 or have had it recently, many of them having picked it up at conferences and work events where face coverings are no longer worn by most people. Some people I know have had Covid-19 four or five times now but, as far as I’m aware I still haven’t had it. I may of course have had a mild infection, without significant symptoms, but I’ve certainly never tested positive for it.
There has been a rapid increase in Covid and ‘flu cases in Ireland recently, but the severity of the situation with respect to the coronavirus is hard to gauge, as there is no longer any routine testing. Take -up of booster vaccines in Ireland has been slow, but I don’t know whether that is increased reluctance or just that it’s difficult to get an appointment. In any case the seasonal booster is generally only available for people over the age of 50 (unless there are other medical reasons).
Finally, let me take this opportunity to wish everyone who has come down with Covid-19 recently a speedy recovery and a healthy New Year!
The 2023 OJAp Annual!
Posted in OJAp Papers, The Universe and Stuff with tags OJAp, The Open Journal of Astrophysics on December 29, 2023 by telescoperI was leafing through my copy of the 2023 Private Eye Annual and thought it would be fun to do a sort of annual for the Open Journal of Astrophysics, so here you are: all 50 of the papers in Volume 6 (2023) in glorious technicolour.


















































I could have linked each image to the relevant paper, but I’m way to lazy to do that!
In case you are interested here is the breakdown into different sections:
- Astrophysics of Galaxies: 10
- Cosmology and Nongalactic Astrophysics: 26
- Earth & Planetary Astrophysics: 1
- High-Energy Astrophysical Phenomena: 0
- Instrumentation and Methods for Astrophysics: 9
- Solar and Stellar Astrophysics: 4
You can see that over half the papers we published are in Cosmology and Nongalactic Astrophysics, and just three arXiv categories account for 90% of the publications. I hope we can increase our diversity in 2024!




