Three New Publications at the Open Journal of Astrophysics

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , , , , , , , on August 10, 2024 by telescoper

It’s Saturday so it’s time once again for another roundup of business at the  Open Journal of Astrophysics. After last week’s summer lull, this week I have three papers to announce, which brings the total we have published so far this year (Vol. 7) to 67 and the total published by OJAp to 182.

First one up, published on 7th August 2024, is “Brightest Cluster Galaxy Offsets in Cold Dark Matter” by Jonathan Katz of Washington University (St Louis, Missouri, USA),  a simulation-based study of the distribution of the position of brightest cluster galaxies relative to the dark matter distribution and its possible use as a cosmological probe.  The authors are Cian Roche (MIT), Michael McDonald (MIT), Josh Borrow (MIT), Mark Vogelsberger (MIT), Xuejian Shen (MIT), Volker Springel (MPA Garching), Lars Hernquist (Harvard), Ruediger Pakmor (Harvard), Sownak Bose (Durham, UK) and Rahul Kannan (York U., Canada). This paper is in the folder marked Astrophysics of Galaxies.

Here is a screen grab of the overlay, which includes the abstract:

 

 

You can read the paper directly on arXiv here.

The second paper to present is “LAMOST J1010+2358 is not a Pair-Instability Supernova Relic” by five authors based in the USA: Pierre Thibodeaux (Chicago), Alexander P. Ji (Chicago), William Cerny (Yale), Evan N. Kirby (Notre Dame) and Joshua D. Simon (Carnegie Observatories) .  As the title makes clear, the paper presents arguments against previous claims that a particular star is not a pair-instability supernova relic. This paper is in the folder marked Solar and Stellar Astrophysics. It was published on Friday August 9th 2024.

The overlay looks like this:

 

 

 

You can read this paper directly on the arXiv here.

Last, but by no means least, comes  “A Pilot Search for Gravitational Self-Lensing Binaries with the Zwicky Transient Facility“, results of a trial search for signals of gravitational lensing of one component in a binary system by a compact companion, with a discussion of future prospects for larger surveys. This one, which was also published on 9th August, is in the folder marked High-Energy Astrophysical Phenomena. The authors are Allison Crossland & Eric C Bellm (U. Washington), Courtney Klein (UC Irvine), James R. A. Davenport (U. Washington), Thomas Kupfer (Hamburg Observatory) and Steven L. Groom, Russ R. Laher & Reed Riddle (Caltech).

Here is a screengrab of the overlay:

To read the accepted version of this on the arXiv please go here.

That’s it for this week. I hope to post another update next weekend.

Have you never contracted Covid-19?

Posted in Biographical, Covid-19 with tags , on August 9, 2024 by telescoper

I’ve taken the liberty of reblogging this post from a blog that I follow, as it is a question that interests me. As far as I know I have never contracted Covid-19, but I think I’m a rare case. I know many people who have had it multiple times. The most I think is five. There was an outbreak at the Euclid Meeting in Rome too, which affected over sixty people. I am hearing through the grapevine that case numbers are rather high at the moment, both in Europe and the USA, but in the absence of any systematic testing it is difficult to know the precise situation.

A couple of months ago I had a nasty cough which I thought might have been Covid-19 but repeated tests came back negative.

In the interest of full disclosure, I am fully vaccinated and boosted. I suppose another booster will be available in the autumn and I’ll take that too.

Anyway, I’d be interested to hear through the comments from anyone who has never had Covid-19 if you feel like divulging such information.

The Woke Olympics

Posted in Film, Sport with tags , , , , on August 9, 2024 by telescoper

I have seen many comments on social media to the effect that the 2024 Paris Olympics have gone “woke”. I agree. Many sports are now mere shadows of what they were a few decades ago let alone the original Greek ideals. Gymnastics for example, the name of which is derived from the Greek gymnós meaning “naked”, nowadays involves competitors with their naughty bits covered up. How woke is that? And the boxers even wear gloves! They’ve all gone soft!

Another example is the fencing. I’m not an expert on this but I did watch quite a lot when I was younger – admittedly not on live TV, but in the form of film recordings. The modern Olympic version of fencing is boring compared with how it used to be. Here are two photographs that illustrate how fencing has gone woke.

For a start, just look at all the protective gear worn by the namby-pamby competitors on the left! And they don’t even use proper swords! It’s health and safety gone mad!

Also, where are the fancy costumes, the stone staircases to run up and down, the chandeliers to swing from, the elaborate hanging tapestries to climb, or the long banqueting tables covered in expensive items there to be trashed? Pathetic!

(P.S. Basil Rathbone (in the still on the right) was actually a seriously good fencer, twice British Army champion in fact, unlike his opponent in the picture Errol Flynn who was so useless that he was a danger to other members of the cast, including Rathbone.)

A Physics Question

Posted in Literature, The Universe and Stuff on August 8, 2024 by telescoper
Frank Benson in the role of Coriolanus (1893)

Is Shakespeare’s play Coriolanus different when performed in the Southern Hemisphere?

Open Access Encounters: The Good, The Bad and the Ugly

Posted in Open Access with tags , , , on August 7, 2024 by telescoper

As it was foretold on Saturday, this afternoon I gave a talk at the 32nd General Assembly of the International Astronomical Union currently taking place in Cape Town, or rather at a side event thereof called Open Access Encounters: The Good, The Bad and the Ugly. I actually gave the last talk in the session, which may or may not mean that I was representing The Ugly

About 50 people attended online plus an unknown number in person, so it was quite a decent size of audiance.

I’m not sure if Slideshare is still working on WordPress, but if not here is a PDF of the slides.

Lessons from Physics and Biology

Posted in Sport, The Universe and Stuff with tags , , , on August 6, 2024 by telescoper

As I’ve mentioned before on this blog, one of my English teachers at school would occasionally give us exercises in creative writing inspired by `Only Connect’ – the epigraph of the novel Howard’s End by E.M. Forster. We were given two apparently disconnected things (usually news items), asked to think of a possible connection between them and write an story joining them together. From time to time when trying to think of something to write about I’ve resorted to playing the same game and am going to do it today.

This time, I thought I would connect two of my own recent blog posts, one about the case of female boxer Imane Khelife and the other about about the death of theoretical physicist TD Lee. What could the connection be?

Tsung-Dao Lee’s most famous work – for which he won the 1957 Nobel Prize with was on parity violation, which was detected experimentally by Chien-Shiung Wu in 1956. Parity is a conserved quantity in classical physics (e.g. in electromagnetism and gravity) and it was believed until the mid-20th century that it would be conserved in the quantum theory of nuclear interactions too. Wolfgang Pauli, for example, criticized Hermann Weyl’s suggestion of a two-component weakly interacting massless particle because it implied parity violation.

The experimental proof of parity violation in some weak interactions led to a much deeper understanding of fundamental physics, including the the idea of chiral gauge interactions, and the development of the standard model of particle physics. Parity is violated in some strong interactions too. Our simple-minded view of how things are changed as a result of an exception to a widely-held assumption. That’s how progress happens.

You might think now that I’m going to write about the fact that double-helix structure of DNA is right-handed, i.e. that it exhibits a form of parity violation, but that’s not it. Or only a little bit. You see, not all DNA is right-handed…

What does this have to do with Olympic boxing? Well, much of the furore about about Imane Khelif is about the (unproven) assertion that she has XY chromosome and is therefore male and should not be allowed to box in the women’s competition. A ‘biological’ female would have XX chromosomes.

It is true in the vast majority of cases that men have XY chromosomes and women have XX chromosomes, but if you read any reasonably modern book on human biology, the statement that ‘females have XX chromosomes’ is preceded by a “usually” or “in most cases”. But there exceptions: some women have XY chromosomes and some men have XX chromosomes; there are also individuals who have an extra chromosome and are XXY.

How can a person be said to be female if they have XY chromosomes? Well, that is because there is a very long journey between the information encoded in genetic material and the expression of that information in form and function. That entire process determines whether an athlete may nor not have an advantage over another. In a rare, sensible article about the Imane Khelif case I found this

Alun Williams, professor of sports and exercise genomics at Manchester Metropolitan University, said that when considering if a person had an unfair advantage it was necessary to look at chromosomes, levels of testosterone and other hormones, as well as the body’s response to testosterone.

“That then is a clinical assessment, which is really very invasive,” Williams said. “Simply looking at someone’s sex chromosomes … is incomplete.”

In most cases individuals with XY chromosomes develop “male” characteristics and those with XX chromosomes develop “female” but there are exceptions. For example, there are women – with ovaries, a uterus and no male sex organs – who have XY chromosomes. These are biologically female, even if their karyotype indicates otherwise. There is much more to biology than genetics, just as there is much more to physics than electromagnetism and gravity.

I don’t know whether Imane Khelif has XY chromosomes or not, and frankly I don’t care. The fact is that she was assigned female gender at birth, has been raised as female, and her gender is female as on her passport. She is a woman. I won’t use the phrase biological woman, because it is silly: every human being is biological. Caster Semenya is female too.

You might not care about this case and prefer top stick to the rigid definition that XX=male and XY=female. I don’t think that’s appropriate in sports: chromosomes don’t compete in sports, people do. I’ve also been accused of being ‘unscientific’ for accepting that the exceptions to a rule. On the contrary, I think such exceptions are how our understanding improves, not only in scientific terms but also in our respect for our fellow human beings.

R.I.P. Tsung-Dao Lee (1926-2024)

Posted in R.I.P., The Universe and Stuff with tags , , , on August 5, 2024 by telescoper

T.D.1.jpg_copyI’ve just heard the sad news of the death at the age of 97 of TD Lee (shown left) who, together with CN Yang, won the Nobel Prize for Physics in 1957 for his work on parity violation in particle physics. I always find it difficult on occasions like this to find ways of describing the work of people of such eminence in fields other than my own, but in this case it turns out I have a personal connection of a sort. Way back in 2006 when I was at Nottingham, the University decided to award Prof. Lee an honorary degree and I was chosen to deliver the oration at the graduation ceremony before spending some time chatting to him with some students. I remember that it was a very hot day and I was wilting under the graduation robes, but he took it all in his stride despite being 80 years old. Anyway, here is the text that I prepared for that occasion, which I hope will serve as a fitting obituary.

 

 

 

 

PROFESSOR TSUNG-DAO LEE

ORATION DELIVERED BY PROFESSOR PETER COLES

ON MONDAY 17 JULY 2006

Chancellor, Vice-Chancellor, Ladies and Gentlemen, it is both a pleasure and a privilege to present Professor Tsung-Dao Lee for the award of an honorary degree.  Professor Lee is a distinguished theoretical physicist whose work over many years has been characterized, in the words of Dr J Robert Oppenheimer, by “a remarkable freshness, versatility and style.”

Tsung-Dao Lee was born in Shanghai and educated at Suzhou University Middle School in Shanghai.  Fleeing the Japanese invasion, he left Shanghai in 1941.  His education was interrupted by war.  In 1945 he entered the National Southwest University in Kunming as a sophomore.  He was soon recognized as an outstanding young scientist and in 1946 was awarded a Chinese Government Scholarship enabling him to start a PhD in Physics under Professor Enrico Fermi at the University of Chicago.  He gained his doctorate in physics in 1950 with a thesis on the Hydrogen Content of White Dwarf Stars, and subsequently served as a research associate at the Yerkes Astronomical Observatory of the University of Chicago in Williams Bay, Wisconsin.

Astronomy is a science that concerns the very large, but it was in the physics of the very small that Professor Lee was to do his most famous work.  After one year as a research associate and lecturer at the University of California in Berkeley, he became a fellow of the Institute of Advanced Study in Princeton and, in 1953, he accepted an assistant professorship position at Columbia University in New York.  Two and a half years later, he became the youngest full professor in the history of Columbia University.  During this time he often collaborated with Chen Ning Yang whom he had known as a fellow student in Chicago.  In 1956 they co-authored a paper whose impact was both immediate and profound.  Only a year later, Lee and Yang were jointly awarded the Nobel Prize in Physics.  Professor Lee was thirty-one at the time and was the second youngest scientist ever to receive this distinction.  (The youngest was Sir Lawrence Bragg who shared the Physics Prize with his father in 1915, at the age of twenty-five; Werner Heisenberg was 31 when his Nobel Prize was announced, in 1932, but he did not receive the prize until the following year.)

It is usually difficult to explain the ideas of theoretical physics to non-experts.  The mathematical language is inaccessible to those without specialist training.  But some of the greatest achievements in this field are so bold and so original that they appear, at least with hindsight, to be astonishingly simple.  The work of Lee and Yang on parity violation in elementary particle interactions is an outstanding example.

Subatomic particles interact with each other in very complicated ways.  In high energy collisions, particles can be scattered, destroyed or transformed into other particles.  But governing these changes are universal rules involving things that never change.  The existence of these conservation laws is a manifestation of the symmetries possessed by the mathematical theory of particle interactions.

Lee and Yang focussed on a particular attribute called parity, which relates to the “handedness” of a particle and symmetry with respect to mirror reflections.  Physicists had previously assumed that the laws of nature do not distinguish between left- and right-handed states: a left-handed object when seen in a mirror should be indistinguishable from a right-handed one.  This symmetry suggests that parity should be conserved in particle interactions, as it is in many other physical processes.  Unfortunately this chain of thought led to a puzzling deadlock in our understanding of the so-called weak nuclear interaction.  Lee and Yang made the revolutionary suggestion that parity is not conserved in weak interactions and consequently that the laws of nature must have a built-in handedness.  A year later their theory was tested experimentally and found to be correct.  Their penetrating insight led to a radical overhaul of the theory of weak interactions and to many further discoveries.  Physicists around the world said “Of course!  Why didn’t I think of that?”

This classic “Eureka moment” happened half a century ago, but Professor Lee has since made a host of equally distinguished contributions to fields as diverse as astrophysics, statistical mechanics, field theory and turbulence.  He was made Enrico Fermi Professor at Columbia in 1964 and University Professor there in 1984.  With typical energy and enthusiasm he took up the post of director of the RIKEN Research Center at Brookhaven National Laboratories in 1998.  He has played a prominent role in the advancement of science in China, including roles as director of physics institutes in Beijing and Zhejiang.

Professor Lee has received numerous awards and honours from around the world, including the Albert Einstein Award in Science, the Bude Medal, the Galileo Galilei Medal, the Order of Merit, Grande Ufficiale of Italy, the Science for Peace Prize, the China National-International Cooperation Award, the New York City Science Award, the Pope Joannes Paulis Medal, Il Ministero dell’Interno Medal of the Government of Italy and the New York Academy of Sciences Award.  His recognition even extends beyond this world, for in 1997 Small Planet 3443 was named in his honour.

Chancellor, Vice-Chancellor, to you and to the whole congregation I present Professor Tsung-Dao Lee as eminently worthy to receive the degree of Doctor of Science, honoris causa.

The Vital Question by Nick Lane

Posted in Biographical, The Universe and Stuff with tags , , , on August 5, 2024 by telescoper

I’ve managed to cross another one off the list of books I’ve had for ages but never read, in the form of biochemist Nick Lane‘s The Vital Question I bought this book several years ago and have no idea why I took so long to get around to it. Given how quickly things are moving in the biosciences these days, it may even be a bit out of date now, but as far as I’m concerned it’s better late than never.

I haven’t studied biology since O-level (1979) but did chemistry as one of four subjects in the first year year of Natural Sciences at Cambridge and I remember some organic chemistry. I wish I had done Biology of Cells then, though, not because I would have carried on with it but because it’s much more interesting than the subject I did take, Crystalline Materials. Probably much of what I would have learnt in 1982-3 is out of date now.

The Vital Question doesn’t ask a single big question but tackles a number of interrelated questions that together comprise a big mystery in the origin of life, basically the apparently sudden appearance of eukaryotic life (i.e. organisms with complex cells, including plants and animals) as distinct from simpler the forms, archaea and bacteria. Among the fascinating issues are how eukaryotes evolved, why there is no missing link, and why eukaryotic cells are all built on a similar model, what made reproductive sex the way it is, and why in the midst of life there has to be death.

One of the great advances in biosciences since the time I didn’t study it is a revolution in the understanding and practical application of genetics, especially through fast DNA sequencing, not only in biology but also in other fields such as medicine, archaeology and forensic science. One of the valuable points that Lane makes is that the success of genetics led to an emphasis on the role of information – because that’s what genes represent – to the detriment of other essential factors in living cells, especially energy. The book points to the relationship, familiar to physicists, that information relates to entropy, but makes it clear that entropy on its own is not sufficient to understand the thermodynamics of, e.g., respiration and reproduction.

This is a recurrent theme in the history of science, actually, that the success of one particular way of looking at phenomenon often seems to convince people that it provides the complete picture, when some subsequent study demonstrates that usually turns out not to be the case. None of this is to argue that genes are unimportant. They undoubtedly are, but so are other factors including reaction kinetics and environment.

Anyway, to address this big question, Lane gives us a tour of the processes involved at a significant level of complexity but the book is so well-written that it’s actually a bit of a page-turner. As I explained at the beginning I haven’t studies any biology for over 40 years so I struggled at first with some of the technical words, but there is a full glossary to help. The rather dreary pictures are less helpful, but altogether is a superb introduction.

One of the aspects of this book I enjoyed greatly is the number of digressions. That might put some people off, but I thought it helped to paint a true picture of the richness of life in all its forms as well the constraints imposed on it. I didn’t know for example that while most mammals (including humans) have X or Y chromosomes, birds are different: they have W and Z (note to physicists: not to be confused with the gauge bosons). Moreover, while the reproductive sex usually indicated by XX is female (homomorphic) and XY is male (heteromorphic), the opposite is true for birds and some reptiles: females are heteromorphic (ZW) and males are homomorphic (ZZ). Why this difference arose I have no idea, but Lane makes some interesting observations about how it may be behind how some male birds develop exaggerated pigmentation and plumage.

Another question that struck me reading this book is why the human genome is so small. Or rather, why so many other genomes are much bigger. For reasons I described in a post a few years ago, I actually have a CD with my own genome on it. Come to think of it, I no longer have a CD drive so have no way of reading it. Anyway, the human comprises about 3 billion base pairs. Some apparently much simpler organisms have genomes much larger than that. We humans are much simpler than we tend to think! Why is that?

Obviously it has been my turn to digress…

I thoroughly recommend this book for a number of reasons, including the excellent explanations of biochemical processes and the fact that it’s written with such obvious enthusiasm and desire to communicated. Above all, though, Lane does what a scientist should do, i.e. he’s honest about the huge gaps in our knowledge. He doesn’t pretend to answer all the questions he asks, but demonstrates the importance of tackling the big issues head on and acknowledging what is known, what is unknown, and what is speculation. That’s a lesson for all science communicators!

Lá Saoire i mí Lúnasa

Posted in Biographical, Education, mathematics, Maynooth with tags , , , on August 5, 2024 by telescoper

Today, Monday 5th August 2024, being the first Monday in August, is a Bank Holiday in Ireland. This holiday was created by the Bank Holiday Act of 1871 when Ireland was under British rule. While the August Bank holiday was subsequently moved to the end of August in England and Wales, it has remained at the start of August in Ireland. Today is also a Bank Holiday in Scotland, though the Scots have the best of both worlds and have a holiday at the end of August too.

The first day of August marks the old pagan festival of Lughnasadh, named after the God Lugh, on which is celebrated the beginning of the harvest season. This coincides with the English Lammas Day one of many Christian festivals with pagan origins. Traditionally this marks the start of the harvest season and is celebrated accordingly, with rites involving the first fruit and bread baked from flour obtained from the first corn. It is also one of the cross-quarter days, lying roughly half-way between the Summer Solstice and the Autumnal Equinox (in the Northern Hemisphere).

It seems to be a tradition in Maynooth that the Bank Holidays in May and August are are adjacent to examinations. This year they start on Wednesday (7th August). I am, however, still on sabbatical so I don’t have any correcting duties. That doesn’t mean I can’t wish all the students taking repeat examinations all the best in their endeavours.

This month is the last of my sabbatical. I officially return to normal duties on 1st September, but that is a Sunday so I won’t return to the office until Monday 2nd September. That is if I have an office. There’s a lot of reorganization going on and currently I don’t know where I’ll be based. At least I know what I’ll be teaching in Semester 1 though: a fourth-year Mathematical physics course on Differential Equations and Complex Analysis and a second-year Engineering Mathematics course. These are not what I would have chosen if I had a free hand (I’d rather teach physics than mathematical methods) but I’ve had it excessively easy for the last year so can’t complain. With a bit of luck I might get a project student or two as well, if the students haven’t forgotten who I am!

Imane Khelif: a Manufactured Scandal

Posted in Politics, Sport with tags , , , , , , on August 4, 2024 by telescoper

Last week’s news from the 2024 Olympics was dominated by the story of Algerian boxer Imane Khelif who defeated her Italian opponent Angela Carini in the Women’s 66kg (Welterweight) division. Carini quit after 46 seconds saying that she was hit so hard that it hurt. It is surprising that she would even enter the Hitting Each Other In The Face event if she were going to complain that her opponent hit her in the face, Anyway, Khelife subsequently won her next bout against Hungarian Luca Hamori to proceed to the semi-finals and is thereby guaranteed a medal. I hope she wins the Gold for all she’s had to put up, not only for the past few days. She seems to have had a tough life generally.

Khelif’s deserved success has ignited what has been called a “gender row”, based on the fact that she and Taiwanese boxer Lin Yu-ting (who is also competing in the 2024 Olympics, in the 57kg category) were disqualified from the IBA World Championships allegedly for failing “gender eligibility tests”. This decision was made suddenly by the Secretary General of the IBA without any due process and the only documentation available is a message on the dodgy social media platform Telegram. The IOC has commented on these so-called “tests”, see here. Here’s an excerpt:

Those tests are not legitimate tests. The tests themselves, the process of the tests, the ad hoc nature of the tests are not legitimate…

There is a thorough piece by Reuters, which links to the IBA’s own statements here (PDF).

You can draw your own inferences about the motivation for the deliberate manufacture of a scandal by the International Boxing Association, but my own view is that it reeks of sour grapes: the IBA, which has been mired in corruption scandals for decades, is no longer recognized by the International Olympic Committee. I think this whole row was deliberately manufactured.

Such are the levels of ignorance and prejudice about anything to do with gender these days that the usual bigots lined up to condemn Khelif and the IOC on the basis of no evidence whatsoever. Widely circulated claims that Khelif has XY chromosomes and/or high levels of testosterone are neither documented nor verified, but that doesn’t seem to matter to the haters.

I’ve seen posts and comments all over the place asserting that women don’t produce testosterone at all. They do. Men produce oestrogen, too. In both cases it’s a question of quantity. Some women have higher testosterone levels than others. So what? If that makes them better at boxing then so be it.

(I even saw a photograph on social media showing that Khelif wears a groin guard under her boxing shorts. Indeed she does: that’s actually mandatory in both men’s and women’s boxing. The person who posted the image however said that wearing a groin guard is something only men do. Clearly he is unaware that a women’s private parts are also sensitive. I guess he’s never had the opportunity to find out.)

It has been argued that “biological factors” have given Imane Khelif an unfair intrinsic biological advantage over competitors. If that were the case then you would expect her to have been an outstanding boxer from the outset. She wasn’t. In fact she had a poor start to her boxing career, losing her first two competitive bouts; she has lost to other women 9 times altogether. Hardly the performance of some kind of superhuman monster as she is being portrayed. She has improved because she has worked hard on her fitness and technique. She is quite tall for her weight division – 1.78 m (5 ft 10 in) –  and has learnt to make use of her long reach, but how is that unfair? I think she might well struggle against an opponent who can get inside and fight at close range. Tall and rangy versus short and powerful is a contrast you often find in these mid-range weight divisions, which is one of the things that make such contests so interesting.

In any case, don’t all athletes have some sort of intrinsic advantage over the rest of us? Michael Phelps certainly did. People who excel at sports often have extreme physical characteristics, whether physical size, muscular strength, cardio-vascular endurance or whatever. Usain Bolt certainly had the advantage of being born Usain Bolt rather than someone else. Which is not to say that he didn’t have to work on making the most of his physique.

There being no documentary evidence to support their claims that Khelif is a man, others have resorted to crude stereotypes based on her looks. I’ve seen the same sort of comments about black female athletes who are accused of looking like men because they don’t conform to white ideals of femininity. A summary of this type of argument is “women should be banned from boxing if they display masculine characteristics, such as being good at boxing”.

None of this alters the fact that Imane Khelif is a woman and indeed a woman who deserves to be celebrated not only her success in her chosen sport, but also for the dignified way she has braved the abuse she has received. I hope she wins Gold and sends the haters into a state of apoplexy.

UPDATE: Imane Khelif did indeed win Olympic Gold by a unanimous decision. Congratulations to her!

 J. K. Rowling is 59.