A neutral pion can decay into two photons. It is therefore not unreasonable to ask the question whether the reverse process – the creation of a neutral pion by colliding two photons – is physically possible and, if not, why not? It is perhaps less reasonable to ask an AI bot these questions. One of my colleagues did just that and found it said “no”, giving the following three answers to the “why not?” question:
I particularly like the second one.
Would anyone like to offer a correct answer through the comments box?
I couldn’t resist sharing this picture I took after lunch of a Norway Maple in St Joseph’s Square on Maynooth University Campus. I like the gradual transitions of colour from green to yellow and orange and red with height. Most of the other trees have lost most of their leaves already.
So James Watson, a deeply unsavoury individual who co-won a Nobel Prize by stealing Rosalind Franklin’s ground breaking research on DNA, and was an unrepentant racist and misogynist, is dead. Lest it be forgotten, here is a collection of authentic quotes that give an insight into his true character.
Yesterday evening I made my way through a rather rainy Dublin to the National Concert Hall for a very enjoyable concert by the National Symphony Orchestra Ireland conducted this time by André de Ridder. Incidentally, the Orchestra has been searching for a new Principal Conductor for some time and as now made an appointment in the form of Alexander Shelley, but he won’t take up the baton until September 2026 so until then there will continue to be a number of guest conductors and, it has to be said, a rather piecemeal programme.
Last night’s performance followed a very typical programme for a concert of classical music: a short piece as an appetiser (often an overture or similar), an instrumental concerto featuring a guest soloist, then a wine break, followed by a full symphony or some other large work. They don’t all follow that format, but many do. I always like it when at least one of the pieces is something I’ve never heard before. That was the case last night.
We started with the orchestral version of Pavane pour une infante défunte, played very well but, as always seems to be the case, rather too slowly for my tastes. That particular piece was on the menu at NCH in March this year and I made the same complaint then. I like the piece a lot, but I wish orchestras wouldn’t take it at a funeral pace!
Next one up was the world premiere of a brand new composition by Bryce Dessner called Trembling Earth. This is a cello concerto and it was written for Russian cellist Anastasia Kobekina. One never knows what to expect from a world premiere but this turned out to tremendous. It’s not a cello concerto of the traditional style – divided into movements – but is in a series of sections, with the cello introducing each theme which is then taken up by the orchestra followed by another, and so on. The texture varies from tough and sinewy to soft and lyrical and the solo passages require great virtuosity, some thing Anastasia Kobekina definitely has.
The composition was apparently inspired by a set of landscapes by Norwegian artist Edvard Munch, so I suppose each section might relate to a particular painting. The sections are very varied, with one based on the theme of Dido’s Lament (When I am laid in Earth...) by Henry Purcell, another with very distinct echoes of Ravel, and another showing more than a nod to Philip Glass in its ostinato sections. At the end of the piece, which is about 25 minutes long, there were immediate cheers and a standing ovation, and the composer came on stage to receive the accolades. “Prediction is very difficult”, said Niels Bohr, “especially about the future”, but I think this work will quickly establish itself in the repertoire. I’d love to hear it again.
The concert would have been worth it just for that one piece, but after the interval we came back for the main course, The Symphony No. 3 in E♭ major (“Eroica”) Ludwig van Beethoven. I’ve blogged about a number of different performances of different Beethoven symphonies over the years, so I’m quite surprised to discover that I’ve never written about this one. It’s hard to know what to say about it really,, except that it’s a magnificent work in its own right as well as being historically important. Before this one, which was published in 1806, symphonies (including not only Beethoven’s First and Second, but those of Mozart, Haydn and others) were much shorter (typically around 20 minutes) and much more constrained in form. This composition – which shares some elements with Mozart’s Symphony No. 39 and was apparently inspired by it – ushered in the era of the epic symphony that culminated with the likes of Mahler and Bruckner. The duration performance we heard last night was about 45 minutes. The first movement, in sonata form, is especially complex.
An interesting point about last night’s performance was the arrangement of the orchestra on stage. From the point of view of the Conductor, the first violins were on the far left (as usual), the cellos and basses were to the front and left, violas to the front and right, and second violins on the far right. I am not sure of the reason for this departure from tradition – second violins are usually adjacent to the firsts, with the cellos and basses on the right – but it was interesting how different it sounded compared to the usual layout.
This superb concert provided a great finish to a very tiring week. Thanks to the NCH for putting on such a wonderful programme. As an added bonus, the rain had stopped by the time it was over so I didn’t get drenched on my way home.
It’s Saturday again, so it’s time for the usual update of the week’s new papers at the Open Journal of Astrophysics. Since the last update we have published another five papers, which brings the number in Volume 8 (2025) up to 168, and the total so far published by OJAp up to 403.
The first paper this week is “Maximizing Ariel’s Survey Leverage for Population-Level Studies of Exoplanets” by Nicolas B. Cowan and Ben Coull-Neveu (McGill University, Canada). This article was published in the folder Earth and Planetary Astrophysics on Tuesday 4th November 2025; it discusses various different schemes to select the mission reference sample for a notional three year transit spectroscopy survey with the European Space Agency’s Ariel mission
The overlay is here:
You can find the officially accepted version on arXiv here.
New Publication at the Open Journal of Astrophysics: "Maximizing Ariel’s Survey Leverage for Population-Level Studies of Exoplanets" by Nicolas B. Cowan and Ben Coull-Neveu (McGill University, Canada)
The second paper of the week is “A substellar flyby that shaped the orbits of the giant planets” by Garett Brown (U. Toronto at Scarborough, Canada), Renu Malhotra (U. Arizona, USA) and Hanno Rein (U. Toronto at Scarborough, Canada). This article was published on Wednesday 5th November 2025, also in the folder Earth and Planetary Astrophysics. It argues that an ancient close encounter with a substellar object offers a plausible explanation for the origin of the moderate eccentricities and inclinations of the giant planets.
The overlay is here:
You can find the official version of this one on arXiv here. The federated announcement on Mastodon is here:
New Publication at the Open Journal of Astrophysics: "A substellar flyby that shaped the orbits of the giant planets" by Garett Brown (U. Toronto at Scarborough, Canada), Renu Malhotra (U. Arizona, USA) and Hanno Rein (U. Toronto at Scarborough, Canada)
Next one up is “The Potential Impact of Primordial Black Holes on Exoplanet Systems” by Garett Brown (U. Toronto at Scarborough), Linda He (Harvard U., USA), and James Unwin (U. Illinois Chicago, USA). This one was also published on Wednesday 5th November 2025, but in the folder Astrophysics of Galaxies. This one is an exploration of the possibility that primordial black holes (PBHs) in our Galaxy, might impact the orbits of exoplanets. The overlay is here:
You can find the official accepted version on arXiv here. The fediverse announcement is here:
New Publication at the Open Journal of Astrophysics: "The Potential Impact of Primordial Black Holes on Exoplanet Systems" by Garett Brown (U. Toronto at Scarborough), Linda He (Harvard U., USA), James Unwin (U. Illinois Chicago, USA)
The fourth paper to report is “The Unhurried Universe: A Continued Search for Long Term Variability in ASAS-SN” by Sydney Petz, C. S. Kochanek & K. Z. Stanek (Ohio State U., USA), Benjamin J. Shappee (U. Hawaii, USA), Subo Dong (Peking University, China), J. L. Prieto (Universidad Diego Portales, Chile) and Todd A. Thompson (Ohio State U., USA). This one was also published on Wednesday November 5th 2025, but in the folder Solar and Stellar Astrophysics. It describes the discovery and investigation of slowly-varying sources in the All Sky Automated Survey for SuperNovae (ASAS-AN) leading to the identification of 200 new variable stars. The overlay is here:
You can find the official published version on arXiv here. The Fediverse announcement follows:
New Publication at the Open Journal of Astrophysics: "The Unhurried Universe: A Continued Search for Long Term Variability in ASAS-SN" by Sydney Petz, C. S. Kochanek & K. Z. Stanek (Ohio State U., USA), Benjamin J. Shappee (U. Hawaii, USA), Subo Dong (Peking University, China), J. L. Prieto (Universidad Diego Portales, Chile) and Todd A. Thompson (Ohio State U., USA)
The fifth and final paper for this week is “Measuring the splashback feature: Dependence on halo properties and history” by Qiaorong S. Yu (Oxford U., UK) and 9 others based in the UK and USA. This was published on Friday 7th November 2025 in the folder Cosmology and Nongalactic Astrophysics. It discusses how the properties of “splashback” features in halo profiles relate to the halo’s assembly history (e.g. mass accretion rate and most recent merger time). The overlay is here:
The officially accepted version can be found on arXiv here. The Fediverse announcement is here:
New Publication at the Open Journal of Astrophysics: "Measuring the splashback feature: Dependence on halo properties and history" by Qiaorong S. Yu (Oxford U., UK) and 9 others based in the UK and USA.
By way of a quick follow-up to yesterday’s post, here’s another Euclid Q1 product. This one is an updated version of the famous “Tuning Fork” representation of galaxy morphology:
Credits: Diagram: ESA/Euclid/Euclid Consortium/NASA, Diagram by J.-C. Cuillandre, L. Quilley, F. Marleau. Images alone: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre, E. Bertin, G. Anselmi
You can click on the image to make it (much) bigger.
A galaxy’s structure is a sign of its formation history and the environment in which it resides. Since early on, astronomers have ordered galaxies according to their visible structure – as a basis to understanding the underlying physics: This panorama of galaxies’ structure shows the ‘classical’ morphological sequence from ellipticals (E, left) to lenticulars (S0) through spirals (S) to irregulars and dwarfs (right). The fork divides barred and unbarred spiral families: originally only SA (unbarred) and SB (barred) galaxies were arranged in a ‘tuning fork’ layout, the addition of SAB (weakly barred) galaxies as a third branch is making this term increasingly challenging to use. Lowercase letters a to d indicate progressively later spiral stages (tighter to looser arms), the trailing m (e.g., SAm) denotes Magellanic, very-late-type systems (patchy, often one-armed). The Milky Way is classified as an SBc galaxy.
Below the main sequence there are three auxiliary panels showing objects not represented in the fork: (1) spiral galaxies seen edge-on, with varying bulge-to-disk ratios and warps; (2) interacting and merging galaxies illustrating gravitationally driven morphological change; and (3) the morphological diversity of dwarf galaxies.
You can read more about this image and the other Q1 results here. You can also find an interactive version of the plot here.
I haven’t posted anything recently about the European Space Agency’s Euclid mission, but I can remedy that by passing on a new image with text from the accompanying press release. This is actually just one of a batch of new science results emerging from the first `Quick Release’ (Q1) data; I blogged about the first set of Q1 results here.
Image description: The focus of the image is a portion of LDN 1641, an interstellar nebula in the constellation of Orion. In this view, a deep-black background is sprinkled with a multitude of dots (stars) of different sizes and shades of bright white. Across the sea of stars, a web of fuzzy tendrils and ribbons in varying shades of orange and brown rises from the bottom of the image towards the top-right like thin coils of smoke.
Technical details: The colour image was created from NISP observations in the Y-, J- and H-bands, rendered blue, green and red, respectively. The size of the image is 11 232 x 12 576 pixels. The jagged boundary is due to the gaps in the array of NISP’s sixteen detectors, and the way the observations were taken with small spatial offsets and rotations to create the whole image. This is a common effect in astronomical wide-field images.
Accompanying Press Release
The above view of interstellar gas and dust was captured by the European Space Agency’s Euclid space telescope. The nebula is part of a so-called dark cloud, named LDN 1641. It sits at about 1300 light-years from Earth, within a sprawling complex of dusty gas clouds where stars are being formed, in the constellation of Orion.
This is because dust grains block visible light from stars behind them very efficiently but are much less effective at dimming near-infrared light.
The nebula is teeming with very young stars. Some of the objects embedded in the dusty surroundings spew out material – a sign of stars being formed. The outflows appear as magenta-coloured spots and coils when zooming into the image.
In the upper left, obstruction by dust diminishes and the view opens toward the more distant Universe with many galaxies lurking beyond the stars of our own galaxy.
Euclid observed this region of the sky in September 2023 to fine-tune its pointing ability. For the guiding tests, the operations team required a field of view where only a few stars would be detectable in visible light; this portion of LDN 1641 proved to be the most suitable area of the sky accessible to Euclid at the time.
The tests were successful and helped ensure that Euclid could point reliably and very precisely in the desired direction. This ability is key to delivering extremely sharp astronomical images of large patches of sky, at a fast pace. The data for this image, which is about 0.64 square degrees in size – or more than three times the area of the full Moon on the sky – were collected in just under five hours of observations.
Euclid is surveying the sky to create the most extensive 3D map of the extragalactic Universe ever made. Its main objective is to enable scientists to pin down the mysterious nature of dark matter and dark energy.
In visible light this region of the sky appears mostly dark, with few stars dotting what seems to be a primarily empty background. But, by imaging the cloud with the infrared eyes of its NISP instrument, Euclid reveals a multitude of stars shining through a tapestry of dust and gas.
I couldn’t resist passing on an unsettling news item about Astronomy Ireland, an Irish Astronomy Club described on its website in the following terms:
Astronomy Ireland is a non profit organisation and the largest national astronomy club in the world relative to population.
The news item concerned revolves around founder and chairperson David Moore (left), who has been held personally liable for multiple employment rights breaches against a former manager, Sonya Martin, at Astronomy Ireland who said she was forced to quit due to a “toxic” work environment and alleged “serious financial irregularities”.
The astronomy club and four members of its management committee, including David Moore, have been ordered to pay nearly €11,000 to the ex-employee, Sonya Martin, after she complained of constructive dismissal to the Workplace Relations Commission (WRC).
Among the allegations reported were that Mr Moore was keeping funds meant for Astronomy Ireland:
David was taking the money and pocketing it as his own income, as opposed to it going back into the society,” Ms Martin said. “The attitude changed towards myself and Ms Doyle after that,” Ms Martin said.
No doubt the money was just “resting in his account”. I mentioned this story to colleagues in the Department and none was surprised, and many (unlike myself) had known about this case for some time. I’ll keep some of the comments to myself, but one said that they gave a lecture (for free, as we academics usually do) to Astronomy Ireland which was filmed without consent. David Moore then sold DVDs of the talk. Where the profits from this went, I have no idea.
These financial shenanigans are dodgy enough but there are some truly bizarre sections of the news report. Here is one:
As the hearings continued into 2025, Mr Moore made repeated objections to being attached personally to the claim, and told Mr Dolan he had not received hearing notifications.
“Emails are unreliable,” he said. When Ms Martin’s solicitor, Mr O’Connell said the notification was sent by post too, Mr Moore said: “The post is unreliable.”
Even stranger, if not directly relevant to the case of Mr Moore, is this:
During the June 2024 hearing, Ms Martin gave evidence that Astronomy Ireland’s office landlord approached her complaining about having to clean up after the junior administrator, Mr G, who was later dismissed.
“The final straw for the landlord was that he had to clean ejaculate from the bathroom after Mr G was in there,” Ms Martin added.
Ewww…
In the interest of full disclosure, I gave a talk to Astronomy Ireland in December 2019. I don’t remember if it was filmed nor whether DVDs were sold, but given what I know now I don’t think I’ll be accepting any more speaking invitations from that organisation.
Update: it seems DVDs of my talk were made and were on sale but are no longer available. They must have sold out.
Today has been a very busy day. I had a one-hour lecture on Partial Differential Equations from 11-12 this morning and a two-hour lecture on Ordinary Differential Equations from 2-4 this afternoon. In between those instead of having a lunch break, I was virtually in Chile giving a talk via Teams about the Open Journal of Astrophysics at LISA 10. That is not LISA as in the Laser Interferometric Space Antenna, but LISA as in Library and Information Services in Astronomy. I was invited to attend this in person, and would have gone, had it not clashed with teaching, as I have never set foot in Chile nor anywhere else in South America.
The talk went well and I had a number of questions and comments.
I got up early this morning to publish a paper taking our total so far to 399. By an unfortunate coincidence there was some problem with the integration between Crossref and our Scholastica platform so the publication didn’t go through properly. When I returned after my afternoon lectures, however, I found that whatever the problem was, it had sorted itself out; the paper is here.
The last talk I gave of this kind was May 2025, and the slides for that talk indicate that OJAp had published 293 papers so we have published over 100 papers in the 6 months since then. Unless there is another glitch tomorrow I expect we’ll reach 400 in the morning.
We present Denario, an AI multi-agent system designed to serve as a scientific research assistant. Denario can perform many different tasks, such as generating ideas, checking the literature, developing research plans, writing and executing code, making plots, and drafting and reviewing a scientific paper. The system has a modular architecture, allowing it to handle specific tasks, such as generating an idea, or carrying out end-to-end scientific analysis using Cmbagent as a deep-research backend. In this work, we describe in detail Denario and its modules, and illustrate its capabilities by presenting multiple AI-generated papers generated by it in many different scientific disciplines such as astrophysics, biology, biophysics, biomedical informatics, chemistry, material science, mathematical physics, medicine, neuroscience and planetary science. Denario also excels at combining ideas from different disciplines, and we illustrate this by showing a paper that applies methods from quantum physics and machine learning to astrophysical data. We report the evaluations performed on these papers by domain experts, who provided both numerical scores and review-like feedback. We then highlight the strengths, weaknesses, and limitations of the current system. Finally, we discuss the ethical implications of AI-driven research and reflect on how such technology relates to the philosophy of science. We publicly release the code at this https URL. A Denario demo can also be run directly on the web at this https URL, and the full app will be deployed on the cloud.
arXiv:2510.26887
Here’s a random picture from the paper:
I haven’t had time to read the paper yet – it’s 270 pages long – but I’m sure it will provoke strong reactions both in favour and against the idea of an AI research assistant. Comments are welcome through the box below.
P.S. The name Denario appears to be derived from the Latin “denarius”, a coin roughly equivalent to a day’s pay for a skilled worker in the days of the Roman Empire. More amusingly, “denarius” is the origin of the Polari word “dinarly”, meaning “money”. If I get time I must generate a Polari version of this manuscript.
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In the Dark 