Archive for the Biographical Category

Nobel Prize for Physics Speculation

Posted in Biographical, Science Politics, The Universe and Stuff with tags , on October 6, 2025 by telescoper

Just to mention that tomorrow (Tuesday, October 7th 2025) will see the announcement of this year’s Nobel Prize for Physics. I must remember to make sure my mobile phone is fully charged so I can be easily reached, although I am likely to be lecturing when the announcement is made.

The announcement of the Nobel Prize for Physics on Tuesday is preceded today (Monday 6th) by the announcement of the Prize for Applications of Physics to Physiology or Medicine, and followed on Wednesday by the Prize for Applications of Physics to Chemistry. You can find links to all the announcements here.

I do, of course, already have a Nobel Prize Medal of my own already, dating from 2006, when I was lucky enough to attend the prize-giving ceremony and banquet.

I was, however, a guest of the Nobel Foundation rather than a prizewinner, so my medal is made of chocolate rather than gold. I think after 19 years the chocolate is now inedible, but it serves as a souvenir of a very nice weekend in Stockholm! Sadly one of the Laureates whose award we were celebrating passed away recently.

Regular readers of this blog may recall that I called it correctly in 2022 when Alain Aspect, John F. Clauser and Anton Zeilinger won the Nobel Prize for Physics that year. I had, however, predicted them every year for many years until they won, and they won’t win it again.

I drew a blank in 2023 when attosecond light pulses were the topic and was completely wrongfooted last when the 2024 Nobel Prize for Physics was awarded to John J. Hopfield and Geoffrey E. Hinton “for foundational discoveries and inventions that enable machine learning with artificial neural networks”. I didn’t see that one coming at all.

I really have no idea who will win it this year, but I’ll suggest that there’s still an outside chance for Michael Berry and Yakir Aharonov for their work on the geometric phase, although if they were going to win they probably would have done so by now.

To find out who the lucky winners you’ll have to wait for the announcement, around about 10.45 (UK/Irish time) on Tuesday morning. I’ll update this post when the wavefunction has collapsed.

Feel free to make your predictions through the comments box below!

Update: I’m not often right but I was wrong again: the 2025 Nobel Prize for Physics goes to John Clarke, Michel H. Devoret and John M. Martinis “for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit”…

https://www.nobelprize.org/prizes/physics/2025/press-release/

Storm Amy

Posted in Biographical, Maynooth with tags , , on October 4, 2025 by telescoper

It’s been an interesting couple of days while Storm Amy worked its way over the island of Ireland and on to Scotland. The worst hit County in the Republic was Donegal but even here in the shelter of County Kidlare there were gusts over 100 hm/h on Friday, and quite a lot of rain as you can see from the first two radar* plots above. Quite a few people, quite reasonably if they were heading towards the weather, went home a bit early on Friday.

Initially the wind was southerly, and it felt surprisingly warm, despite the rain, but by this morning it had veered westerly, the rain had turned to showers, and the wind has now moderated substantially.

I spent some time this afternoon clearing up leaves and small branches that had fallen during the storm, as well as looking for signs of damage. But all’s well. No power cuts either. My big worry however is this tree just outside my house:

It is far too tall for its location, and has been leaning alarmingly for some time. If it topples in the direction it is leaning it will hit my house. I’ve been on to Kildare County Council a few times about it, actually. I don’t want them to chop it down, but I do think they should cut back the upper branches so that if it falls it won’t hit either mine or my neighbour’s house. Unfortunately, they’ve refused to do anything at all. Time for another go at them, I think. It will cost them a lot less to deal with it now than the sum they will have to pay me if serious damage is caused by their negligence.

*In case you’re interested, Met Éireann’s weather radars are located at Dublin and Shannon, and operate at 5.64 GHz (C-band).

Supplementary Information

Posted in Biographical, Crosswords, Literature with tags , , on September 29, 2025 by telescoper

Regular readers of this blog know that I have a habit of reading the Times Literary Supplement which I buy not only for the book reviews, but also for its excellent crossword. I’ve even won the crossword competition prize a few times. You can find an assortment of posts related to the TLS here.

Recently the Times Literary Supplement underwent something of a makeover, changing the design and switching from a weekly to fortnightly publication. The first new-style issue was published on September 5th. Here is the cover:

The cover article is about the possible identity of the “Mr W.H.” to whom William Shakespeare dedicated his collection of Sonnets; see here. I may write something about that in the not too distant future, as I’ve been reading these again recently.

Anyway, my subscription definitely specifies a “weekly print edition delivered to my door”, so that has gone out the window. I wasn’t best pleased to have the terms of my subscription changed unilaterally like that. Of course I could just read the online edition, but I don’t like reading too much on a screen. I’ve never adapted to reading books on a Kindle either. And crosswords are impossible that way. The old format TLS was rather like a tabloid newspaper, which I found easy to read and handle, and of 28 pages per edition. The new format has 48 pages (which is not 2 times 28) and is rather cramped and crowded and with heavier paper to make it look there’s more to it than there is.

The look and feel they seem to have gone for is “Generic Weekend Supplement”, as you can see if you compare it with last week’s Irish Times Weekend Magazine:

The latter supplement has 52 pages instead of 48 and has more advertisements inside but is otherwise similar.

So why mention this? Well one thing is that the number of crosswords provided by the TLS per year has now reduced by half, which to me reduces the value of the subscription significantly. Moreover, the first issue of the new style supplement was published on September 5th, but didn’t arrive through my letterbox until 24th September. That’s 19 days. The deadline for entries to the crossword competition was September 15th.

Now the old-style issues used to take about 10 days to cross the Irish Sea, which I thought was bad, but 19 days is just awful. One theory of this is that the TLS launches issues with the same momentum, so that the new edition, having about twice the mass, has half the speed and therefore takes roughly twice as long to reach the subscriber. Checking the envelope, incidentally, I see that it was postmarked Bratislava. There must be a very cheap – but slow – way of sending post from the UK to Ireland via Slovakia.

Anyway, I’ve decided not to renew my subscription to the TLS, as I did with Private Eye recently. I cancelled my subscription to the Eye not because I was offended by anything in it, but because it was taking a ridiculously long time to arrive. I can still pick up copies of both publications in the local newsagent. I’m sure Paddy will keep copies of both to one side if I ask him.

Alternatively, I might switch from the TLS to the London Review of Books or some similar. Does anyone have recommendations?

Summer’s Over

Posted in Biographical, Cricket, Maynooth with tags , , , on September 28, 2025 by telescoper

I’ve done quite a few posts recently about the ending of summer – the Autumnal Equinox, the resumption of teaching, the start of a new season at the National Concert Hall are three indicators – but now we really have reached which I regard as the definite conclusion. Yesterday saw the last day of the last round of matches in cricket’s County Championship.

I haven’t followed cricket very closely since I moved to Ireland, but I do look and see how Glamorgan are getting on. The County Championship started very poorly for them, with a thrashing by Middlesex, but they improved substantially and went into the last round of matches secure in 2nd place of Division 2. They lost their last match in Cardiff against a team from the Midlands, by 7 wickets – a game that actually ended on Friday – but they still finished second. That means that they get promoted to Division 1 for the first time in 21 years.

I wouldn’t bet against them being relegated straight away, though. Last time they got promoted (in 2004) they played just one season (2005) in the First Division, during which they lost 14 of their 16 matches, and dropped back down. They almost got promoted in 2010 but were pipped for second place by Worchestershire, who were the beneficiaries of an exceedingly generous – let’s put it that way – declaration by Sussex that allowed them to win their last match. Anyway, to avoid the drop next season Glamorgan need to improve their pace attack considerably. I wonder who, if anyone, they’ll sign?

Glamorgan plays an important role in the international cricket ecosystem, especially with the Ashes coming up. Many of Australia’s star players – including Marnus Labuschagne, Michael Neser, and Usman Khawaja – only came to prominence after stepping up to the big time to play for Glamorgan.

Knowing that the cricket season was almost over, on Friday I decided to give my front lawn one last mow too. The mower is now in the shed until next spring. Leaves have been falling for some time already, so I swept up what I could after cutting the grass. That reminds me to share this, which I found on Bluesky:

I really hate those things

Anyway, we have completed one week of teaching at Maynooth University which passed off reasonably smoothly. I only had one timetabling glitch, but that was resolved trivially by just swapping two sessions. This year the Department of Physics has quite a lot of students in the final-year on the Physics with Astrophysics programme, run before the merger by the Department of Experimental Physics. Now we’re combined we can share the load and I’ll be supervising a couple of students on an astrophysics project, which will be a new experience. I haven’t really taught much astrophysics since coming here nearly eight years ago, so this will make a nice change.

R.I.P. George F. Smoot (1945-2025)

Posted in Biographical, R.I.P., The Universe and Stuff with tags , , , , , , on September 26, 2025 by telescoper
George F. Smoot (1945-2025)

I’m very sad to have to report the death, at the age of 80, of eminent cosmologist George Smoot, who passed away at his home in Paris on 18th September. The news has been reported in France, where George had been living in recent years, but doesn’t seem to have been covered in the international media yet. I thought I would just record some personal relfections and reminiscences here, rather than try to pre-empt the official biographies.

George Smoot was an experimental astrophysicist who is best known for his research in observational cosmology, particularly on the cosmic microwave background. In 2006, jointly with John Mather, he was awarded the Nobel Prize for Physics for measurements made by the COBE satellite that, without exaggeration, ushered in a new era of cosmology. George led the paper Structure in the COBE Differential Microwave Radiometer First-Year Maps that reported the first detection of variations in temperature of the cosmic microwave background across the sky predicted by theories of cosmological structure formation.

I was fortunate enough to meet George many times over the years and to get to know him quite well. The first time was at a meeting in Durham for which this was the conference photo:

George is just to the left of centre in the front row with the red-and-white sweater.

What I remember about that meeting is that I gave a contributed talk there (a short one, because I was a mere postdoc at the time). Some time after that, George Smoot gave an invited talk during the course of which he mentioned (positively) the work I had spoken about. I was gobsmacked to have my little contribution recognized by someone so eminent, and it did wonders for my scientific self-confidence. I got the chance to have a conversation with George in person some time later at that meeting and found him very good value: he was both interesting and amusing to talk to. He was someone who took mentorship seriously, and didn’t confine it to those people he was working with directly.

Over the years I met George regularly at scientific meetings, including numerous times at the (then) Daniel Chalonge schools in Sicily and in Paris where we often chatted about science and other things over coffee breaks and dinner. I always found him hugely knowledgeable about many things, but he also had an almost child-like curiosity about things he didn’t previously know. He didn’t quite jump up and down with excitement when he learnt something interesting, but almost. He could also be very direct when disagreeing, which meant that some people found him a bit abrasive. He fell out with other members of the COBE time when he threw away the agreed protocol for the announcement of results in 1992. That caused a lot of bad feeling at the time, but it seems that by the time the Nobel Prize was awarded, some degree of reconciliation had been achieved. I was lucky enough to attend the Prize Ceremonies and at the ball afterwards chatted with both George and John Mather who seemed on very amiable terms then.

Anyway, in the early noughties George invited me to spend some time at the Lawrence Berkeley Laboratory, a visit that I enjoyed enormously. He was a very generous and thougtful host and I was looked after very well. One day at LBL he asked me if the hotel was OK. I replied that it was, but one thing I didn’t like about staying in a hotel was that I liked to cook and that was impossible in a hotel room. I thought nothing more of that conversation until the end of the day when George appeared and asked me if I wanted to “do dinner” at his house that evening. I answered in the affirmative so he drove me to his house, which was very fancy, set into the hillside overlooking Berkeley – like the sort of place I imagine a film star would live – and had a very large and well-provisioned kitchen.

It soon became clear that I’d misunderstood the invitation, in that “do dinner” didn’t mean “eat dinner” but “make dinner”. Although I was slightly taken aback I set about finding what he had in the refrigerator and on the shelves. There being a plentiful supply of spices, I decided to make a tandoori-style dish of chicken baked with yoghurt, with a couple of side dishes, none of which took long to cook. When everything was getting ready I wanted to add some lemon juice but couldn’t find any lemons in the fridge. I asked George if he had any lemons, at which point he showed me into the garden where he had several lemon trees in full fruit. I’ve never lived anywhere that this would be possible! I think he enjoyed the dinner because he paid me back a few days later with a dinner at Chez Panisse. He was quite the bon viveur.

(After that short visit, I was planning to spend a sabbatical year in Berkeley in 2005, but the United States Embassy in London put paid to that idea and I went to CITA in Toronto instead.)

The last encounters I had with George were online; he was in the audience when I gave talks in the Chalonge-de Vega series organized by Norma Sanchez in 2021 (here and here). I think he had already moved to Paris by that time. The first of these talks was about open access publishing in astrophysics; George subsequently co-authored a paper in the Open Journal of Astrophysics.

My favourite quote from George came during a discussion we had at Berkeley when I suggested that some methods used for studying the cosmic microwave background could be applied to the distribution of galaxies. His response was “Galaxies are shit”. To avoid offending my friends who work on galaxies, what he meant by that was that he thought galaxies were too messy for any statistical measurements to sufficiently reliable to compete with the CMB. I think he would have preferred a universe in which all galaxies were identical, like electrons.

I’m sure many others will have their own personal reflections on their interactions with George Smoot, but he also had a huge influence on many people who never met him personally, through his enormous contributions to astrophysics and cosmology. We will no doubt read many professionally-written official obituaries in days to come, but all I can say in a personal blog post is that he was a character, a very original thinker, a fine scientist, and a very nice man. Along with many others, I will miss him enormously.

Rest in Peace, George Fitzgerald Smoot III (1945-2025) .

Update: Here is an `In Memoriam’ piece from from the Berkeley Lab.

That Magic Gene…

Posted in Biographical, Covid-19, History, LGBTQ+ with tags , , , , on September 25, 2025 by telescoper

While writing yesterday’s post about the evolution of languages, and the importance of genetic information in reconstructing the story thereof, I was reminded of a post I wrote a while ago about the peculiarities of my own genome, a listing of which I have on a CD-ROM at home. There’s not as much data involved as you might think: it’s effectively only about 800 MB.

Anyway, to cut a long story short, it turns out that I have the CCR5-Δ32 genetic mutation. Not only that, I have it twice over, in that I have two copies (homozygotes). I must therefore have inherited it from both parents. This mutation confers virtually complete immunity from HIV-1 infection.

The above graphic shows that more than 10% of the population in Northern Europe has this mutation in just one allele (i.e. they are heterozygotic). To get an estimate of how many have the form on two alleles (i.e. homozygotic) form you can just square that number, so around 1% or more.

It is thought that the CCR5-Δ32 mutation occurred in a single individual in Scandinavia around 1,000 years ago. When I wrote that post I tacitly assumed that it had propagated passively, i.e. without any particular selection, to the modern era. That it reached 10% of the population starting from just one individual surprised me, but I let it pass.

More recently, I came across a paper about how advances in genetics have impacted epidemiological studies. In the abstract it shows that my assumption was probably incorrect.

Algorithms of molecular evolutionary theory suggested that the CCR5-Δ32 mutation occurred but once in the last millennium and rose by strong selective pressure relatively recently to a ~10% allele frequency in Europeans. 

It goes on to say this:

Several lines of evidence support the hypothesis that CCR5-Δ32 was selected due to its protective influence to resist Yersinia pestis, the agent of the Black Death/bubonic plague of the 14th century.

I didn’t mention in yesterday’s post that evidence of the plague bacillus is found in a significant number of prehistoric human remains and this almost certainly played a role in the ebb and flow of populations. In the context of CCR5-∆32, however it seems that it may have been advantageous to carry it long before the arrival of HIV/AIDS. That might account for it reaching the relatively high level that it did.

Among the downsides, however, as the article explains, are an increased risk for encephalomyelitis and death when infected with the West Nile virus. Hopefully further cohort studies of people with this mutation will help elucidate its effect on other diseases.

By the way, in contrast to most people I know, I have still never had Covid-19…

Autumnal Equinox 2025

Posted in Biographical, Education, Maynooth, The Universe and Stuff with tags , on September 22, 2025 by telescoper

Just a note to say that the Autumnal Equinox (in the Northern hemisphere) takes place this evening (Monday 22nd September 2025)  at 19.20 Irish Summer Time (18.20 UTC).

Although  the term `equinox’  refers to a situation in which day and night are of equal length, which implies that it’s a day rather than a specific time, the astronomical equinox is more accurately defined by a specific event, i.e. when the plane defined by Earth’s equator passes through the centre of the Sun’s disk (or, if you prefer, when the centre of the Sun passes through the plane defined by Earth’s equator). Day and night are not necessarily exactly equal on the equinox, but they’re the closest they get. From now on days in the Northern hemisphere will be shorter than nights and they’ll get shorter still until the Winter Solstice on Sunday 21st December 2024 at 3.03 pm Irish Time.

Many people take the autumnal equinox to be the end of summer. There is a saying around these parts, however, that `Summer is Summer to Michaelmas Day’ (September 29th), which is not until next week. I must say, though, though it doesn’t feel particularly summery this morning as there is a chilly wind blowing from the North.

Anyway, make the most of the Equinox because there is a rumour circulating that The Rapture will occur tomorrow (Tuesday 23rd September).

On Cosm(et)ology

Posted in Biographical, The Universe and Stuff with tags , , , , , on September 16, 2025 by telescoper

Every now and then I clean out my spam folder, usually finding a number of junk conference invitations. Most of them are tedious but sometimes I get a funny one that I post on here. The latest batch included this one.

I suppose the confusion between cosmology and cosmetology was to be expected at some point. I am of course something of an expert on ageing (sic), having managed to age quite considerably over the last 60-odd years. I also have a strong interest in the make-up of the Universe, especially through the foundations of physics. I’d even be tempted to attend the meeting were I not teaching on the dates concerned. I might reply suggesting they invite a colleague of mine here in Ireland, Dermot O’Logical.

Anyway, this gives me an excuse to post the following rehash of one of my old posts, this I one that dates from 2008..

–o–

When asked what I do for a living, I’ve always avoided describing myself as an astronomer, because most people seem to think that involves star signs and horoscopes. Anyone can tell I’m not an astrologer anyway, because I’m not rich. Astrophysicist sounds more impressive, but perhaps a little scary. That’s why I usually settle on “Cosmologist”. Grandiose, but at the same time somehow cuddly.

I had an inkling that this choice was going to be a mistake at the start of my first ever visit to the United States, which was to attend a conference in memory of the great physicist Yacov Borisovich Zel’dovich, who died in 1989. The meeting was held in Lawrence, Kansas, home of the University of Kansas, in May 1990. This event was notable for many reasons, including the fact that the effective ban on Russian physicists visiting the USA had been lifted after the arrival of glasnost to the Soviet Union. Many prominent scientists from there were going to be attending. I had also been invited to give a talk, the only connection with Zel’dovich that I could figure out was that the very first paper I wrote was cited in the very last paper to be written by the great man.

I think I flew in to Detroit from London and had to clear customs there in order to transfer to an internal flight to Kansas. On arriving at the customs area in the airport, the guy at the desk peered at my passport and asked me what was the purpose of my visit. I said “I’m attending a Conference”. He eyed me suspiciously and asked me my line of work. “Cosmologist,” I proudly announced. He frowned and asked me to open my bags. He looked in my suitcase, and his frown deepened. He looked at me accusingly and said “Where are your samples?”

I thought about pointing out that there was indeed a sample of the Universe in my bag but that it was way too small to be regarded as representative. Fortunately, I thought better of it. Eventually I realised he thought cosmologist was something to do with cosmetics, and was expecting me to be carrying little bottles of shampoo or make-up to a sales conference or something like that. I explained that I was a scientist, and showed him the poster for the conference I was going to attend. He seemed satisfied. As I gathered up my possessions thinking the formalities were over, he carried on looking through my passport. As I moved off he suddenly spoke again. “Is this your first visit to the States, son?”. My passport had no other entry stamps to the USA in it. “Yes,” I said. He was incredulous. “And you’re going to Kansas?”

This little confrontation turned out to be a forerunner of a more dramatic incident involving the same lexicographical confusion. One evening during the Zel’dovich meeting there was a reception held by the University of Kansas, to which the conference participants, local celebrities (including the famous writer William Burroughs, who lived nearby) and various (small) TV companies were invited. Clearly this meeting was big news for Lawrence. It was all organized by the University of Kansas and there was a charming lady called Eunice who was largely running the show. I got talking to her near the end of the party. As we chatted, the proceedings were clearly winding down and she suggested we go into Kansas City to go dancing. I’ve always been up for a boogie, Lawrence didn’t seem to be offering much in the way of nightlife, and my attempts to talk to William Burroughs were repelled by the bevy of handsome young men who formed his entourage, so off we went in her car.

Before I go on I’ll just point out that Eunice – full name Eunice H. Stallworth – passed away suddenly in 2009. I spent quite a lot of time with her during this and other trips to Lawrence, including a memorable day out at a pow wow at Haskell Indian Nations University where there was some amazing dancing.

Anyway, back to the story. It takes over an hour to drive into Kansas City from Lawrence but we got there safely enough. We went to several fun places and had a good time until well after midnight. We were about to drive back when Eunice suddenly remembered there was another nightclub she had heard of that had just opened. However, she didn’t really know where it was and we spent quite a while looking for it. We ended up on the State Line, a freeway that separates Kansas City Kansas from Kansas City Missouri, the main downtown area of Kansas City actually being for some reason in the state of Missouri. After only a few moments on the freeway a police car appeared behind us with its lights blazing and siren screeching, and ushered us off the road into a kind of parking lot.

Eunice stopped the car and we waited while a young cop got out of his car and approached us. I was surprised to see he was on his own. I always thought the police always went around in pairs, like low comedians. He asked for Eunice’s driver’s license, which she gave him. He then asked for mine. I don’t drive and don’t have a driver’s license, and explained this to the policeman. He found it difficult to comprehend. I then realised I hadn’t brought my passport along, so I had no ID at all.

I forgot to mention that Eunice was black and that her car had Alabama license plates.

I don’t know what particular thing caused this young cop to panic, but he dashed back to his car and got onto his radio to call for backup. Soon, another squad car arrived, drove part way into the entrance of the parking lot and stopped there, presumably so as to block any attempted escape. The doors of the second car opened and two policemen got out, kneeled down and and aimed pump-action shotguns at us as they hid behind the car doors which partly shielded them from view and presumably from gunfire. The rookie who had stopped us did the same thing from his car, but he only had a handgun.

“Put your hands on your heads. Get out of the car. Slowly. No sudden movements.” This was just like the movies.

We did as we were told. Eventually we both ended up with our hands on the roof of Eunice’s car being frisked by a large cop sporting an impressive walrus moustache. He reminded me of one of the Village People, although his uniform was not made of leather. I thought it unwise to point out the resemblance to him. Declaring us “clean”, he signalled to the other policemen to put their guns away. They had been covering him as he searched us.

I suddenly realised how terrified I was. It’s not nice having guns pointed at you.

Mr Walrus had found a packet of French cigarettes (Gauloises) in my coat pocket. I clearly looked scared so he handed them to me and suggested I have a smoke. I lit up, and offered him one (which he declined). Meanwhile the first cop was running the details of Eunice’s car through the vehicle check system, clearly thinking it must have been stolen. As he did this, the moustachioed policeman, who was by now very relaxed about the situation, started a conversation which I’ll never forget.

Policeman: “You’re not from around these parts, are you?” (Honestly, that’s exactly what he said.)

Me: “No, I’m from England.”

Policeman: “I see. What are you doing in Kansas?”

Me: “I’m attending a conference, in Lawrence..”

Policeman: “Oh yes? What kind of Conference?”

Me: “It’s about cosmology”

At this point, Mr Walrus nodded and walked slowly to the first car where the much younger cop was still fiddling with the computer.

“Son,” he said, “there’s no need to call for backup when all you got to deal with is a Limey hairdresser…”.

17 Years In The Dark

Posted in Biographical, The Universe and Stuff with tags , , , on September 15, 2025 by telescoper

I just received the following message from WordPress.com reminding me that today is the 17th anniversary of my registration with them, which is when I took my first step into the blogosphere. That was way back on 15th September 2008…

I actually wrote my first post on the day I registered but, unfortunately, I didn’t really know what I was doing on my first day at blogging – no change there, then – and I didn’t actually manage to figure out how to publish this earth-shattering piece. It was only after I’d written my second post that I realized that the first one wasn’t actually visible to the general public because I hadn’t pressed the right buttons, so the two appear in the wrong order in my archive. Such was the inauspicious beginning of this “shitty WordPress blog”!

Since then I have published 7,418 blog posts posts (including this one), which have altogether received over 5.8M page views from 2.4M unique visitors. That doesn’t include the 2000+ subscribers who receive posts by email nor those who view the federated version via the fediverse. The largest number of hits I have received in a single day is still 8,864 (in 2014, at the peak of the BICEP2 controversy).

This time next year this blog will be an adult! Having gone this far with it, I might as well continue until I retire…

P.S. I noticed recently that this blog is getting some traffic from China, where it was previously banned. along with all other WordPress.com sites. It’s interesting that this ban appears to have been lifted.

A Decade of Gravitational Waves

Posted in Biographical, The Universe and Stuff with tags , , , , , , on September 14, 2025 by telescoper

This is just a quick post to mark the fact that it is now ten years to the day since the first detection of gravitational waves by Advanced LIGO. The acronym LIGO stands for Laser Interferometer Gravitational-wave Observatory, by the way. It wasn’t until February 11th 2016 that the result was announced at a press conference (which I blogged about here), but the signal itself arrived on 14th September 2015, exactly a decade ago; the name given to the event was GW150914.

Here are the plots for that first one:

LIGO

That first signal corresponded to the coalescence of two black holes, of masses 29 and 36 times the mass of the Sun and produced a large response in the detectors very soon after Advanced LIGO was switched on. There’s synchronicity for you! The LIGO collaboration have done wondrous things getting their sensitivity down to such a level that they can measure such a tiny effect, but there still has to be an event producing a signal to measure. Collisions of two such massive black holes are probably extremely rare so it’s a bit of good fortune that one happened just at the right time. Actually it was during an engineering test.

There have been many subsequent detections and even more candidates waiting to be confirmed- here’s a full list. The official LIGO site states there are 90 confirmed detections, the 4th observational run (O4) (which is due to end in November 2025) has already found 200 candidates. The latest compilation of gravitational-wave transient sources can be found here.

Most of the detections have been binary black hole mergers, but I particularly remember the excitement in 2017 surrounding the first merger of a neutron star with a black hole. It was fun that rumours started to spread via this blog as people outside the LIGO/transient source community used a comments thread here to share information of what various telescopes were looking at. That was in August 2017, just over 8 years ago.

Anyway, here’s to the next decade. Assuming NSF does not follow Trump’s plan to slash the LIGO budget.