Archive for the The Universe and Stuff Category

Memories of My First Paper

Posted in Biographical, The Universe and Stuff with tags , on September 28, 2020 by telescoper

The death of John Barrow reminded me of a post I did some years ago about my first ever publication, which was published on 15th September 1986 while I was doing my DPhil at Sussex under John’s supervision. I’m mentioning
it hereby way of a postscript to yesterday’s piece.

Here is the front page:

mnras_paper

This was before the days of arXiv so there isn’t a copy on the preprint server, but you can access the whole article here on NASA/ADS.

All right. I know it’s a shitty little paper. But you have to start somewhere!

I’m particularly sad that, looking back, it reads as if I meant to be very critical of the Kaiser (1984) paper that inspired it. I still think that was a brilliant paper because it was based on a very original idea that proved to be enormously influential. The only point I was really making was that a full calculation of the size of the effect Nick Kaiser had correctly identified was actually quite hard, and his simple approximation was of limited quantitative usefulness. The idea was most definitely right, however.

I was just a year into my PhD  DPhil when this paper came out, and it wasn’t actually on what was meant to be the subject of my thesis work (which was the cosmic microwave background), although the material was related.

This paper provides two excellent illustrations of what a good supervisor John was. I was a bit stuck with the project that John had assigned me and eventually admitted to him that I was having problems getting anywhere. I thought he’d assume I was useless and suggest that someone else should supervise me. But no. He said he realised it was a hard problem and sometimes it’s good to think about something else when you’re stuck. So he asked me to look at cluster clustering for a bit. I told him what I found and he said I should write this up as a paper, which I did. Most importantly however the trick I used in simplifying the calculations in this paper turned out to be applicable to the first problem, hotspots in the cosmic microwave background, which led a success in the project and to my second paper. We were both delighted that everything turned out well with that original project.

My original draft of this first paper had John Barrow’s name on it, but he removed his name from the draft (as well as making a huge number of improvements to the text). At the time I assumed that he took his name off because he didn’t want to be associated with such an insignificant paper, but I later realized he was just being generous. It was very good for me to have a sole-author paper very early on. I’ve taken that lesson to heart and have never insisted – unlike some supervisors – in putting my name on my students’ work.

R.I.P. John D Barrow (1952-2020)

Posted in Biographical, The Universe and Stuff with tags on September 27, 2020 by telescoper

My heart is filled with sorrow as I find myself having to pass on some very sad news. I have just heard of the death, yesterday, at the age of 67, of esteemed physicist, mathematician, author and polymath John Barrow. With his passing, one of cosmology’s brightest lights has gone out.

John Barrow was my thesis supervisor. Words can’t express how much I owe him for his advice and encouragement not only during my graduate studies but also throughout the 35 years that have elapsed since I started my career, as a research student at Sussex University.

John had an extraordinary mind that combined immense mathematical gifts with an encyclopedic knowledge of all kinds of literature and a wonderful flair for writing. He wrote dozens of books and a theatre play as well as hundreds of scientific articles. He was a whirlwind of ideas who had an uncanny knack of finding clever ways to crack previously unsolved problems. That he was happy to share these ideas with his students is a credit to his intellectual generosity. He inspired dozens of researchers early in their careers and continued to inspire them when they became not so young.

On a personal level, John was rather reserved and, despite his being a talented and confident public speaker, I always felt he was a rather shy person. He was a committed Christian and a regular churchgoer though he didn’t talk much about his private religious beliefs in the Department.

It is also interesting that, despite writing a number of superb popular books, giving public lectures and being a regular guest on radio programmes he steadfastly refused to appear on television. He just didn’t want to become a TV celebrity, though I suspect that if he did he would have been rather good at it.

Although I didn’t see as much of him in recent years as I would have liked, John was a member of the RAS Club which gave me the opportunity to see and talk to him fairly frequently. I always found him a very agreeable dining companion. We usually discussed sport on such occasions rather than science, actually. John was a talented middle-distance runner in his younger days and he gave me a lot of advice about training, etc, when I started running marathons. We also shared an interest in football – at which he was rather good, having had a trial for Chelsea Juniors – and we played together quite a few times in Sussex days. I remember him as a quality midfielder with a terrific engine, though he was not a natural goalscorer.

John also had a very dry and sometimes lugubrious sense of humour. I remember sending him a congratulatory email in 2003 when I found out he had been made a Fellow of the Royal Society. He replied thanking me but pointing out his joy at having been elected was tempered by the fact that the first official communication he got from Carlton House was a rather substantial bill for the subscription and a form on which to enter details to be used in an obituary.

It was through the RAS Club that I first heard, about a year ago that John was suffering from cancer. For a time he responded well to treatment but a few weeks ago I heard that his condition had deteriorated to the extent that only palliative care was possible. That news came as a shock as he always seemed so healthy and ageless that one imagined him to be indestructible. Today’s news was not unexpected but still distressing. The end came more quickly than we imagined but at least he was at home among his loved ones when he passed away.

I send heartfelt condolences to Elisabeth and the rest of John’s family, and friends and colleagues at Cambridge and elsewhere.

UPDATE: An obituary of John, written by Michael Rown-Robinson, is now available online on the Guardian website.

Rest in peace, Professor John D Barrow FRS (1952-2020).

Astronomy Photograph of the Year 2020

Posted in Art, The Universe and Stuff with tags , , , , on September 24, 2020 by telescoper

Very busy today so I only have time to share a this stunning picture, the overall winner of the 2020 Astronomy Photographer of the Year, Andromeda Galaxy at Arm’s Length? by Nicolas Lefaudeux (France).

 

Photo credit: Nicolas Lefaudeux/2020 astronomy photographer of the year

The Autumnal Equinox 2020

Posted in Biographical, Maynooth, The Universe and Stuff with tags , , on September 22, 2020 by telescoper

So here we are then. The Autumnal Equinox (in the Northern hemisphere) takes place this afternoon at 14.31 Irish Time (13.31 UT).

Though  the term `equinox’  refers a situation in which day and night are of equal length which implies that it’s a day rather than a specific time, the equinox is more accurately defined by a specific event 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.

For many people the autumnal equinox is taken to be the end of summer, though there is a saying around these parts that `Summer is Summer to Michaelmas Day’ (September 29th). Looking back over the posts I’ve written at this time of year since I started blogging in 2008, it’s noticeable how many times we’ve had a window of good weather around the autumnal equinox. In Wales such a warm spell in late September is called Haf Bach Mihangel – “the little summer of St Michael”.

Here’s a sample excerpt from the post I wrote in 2008 on this:

The weather is unsettling. It’s warm, but somehow the warmth doesn’t quite fill the air; somewhere inside it there’s a chill that reminds you that autumn is not far away.

I find this kind of weather a bit spooky because it always takes me back to the time when I left home to go to University, as thousands of fledgling students are about to do this year in their turn.

It has been quite warm here in Maynooth recently too. Last night I mowed the lawn in the evening sunshine, which may well be the last time I do that until spring. The weather turned a bit colder overnight and the weather forecast suggests the little summer may be over.

Anyway, this is Welcome Week in Maynooth and, barring any sudden changes of plan, we’re due to start teaching on Monday 28th September. I’ve been keeping an eye on the registrations of students as they come in as well as starting to get my notes, problem sheets, recordings and other teaching materials together. I have to say that hasn’t been helped by the decision to install a new fire alarm system in the Science Building this week. I had to go home early because of the constant din of the sounders being tested.

I have to admit I’m very apprehensive about the forthcoming semester and beyond. It’s impossible to predict where we will be by the next equinox in March, or even by the Solstice in December. Covid-19 cases are increasing and it doesn’t seem that anyone has a clue how to stop the `second wave’ surging through the population this autumn. The September equinox is often said to to be the start of Astronomical Autumn. This year more than ever it seems to herald that Winter is coming.

Twelve Years in The Dark!

Posted in Biographical, The Universe and Stuff with tags on September 15, 2020 by telescoper

When I logged onto WordPress today I received a message that it was the 12th anniversary of my registration with them as a blogger, 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.

If you’re interested in statistics then, as of 13.00 Irish Summer Time Today today, I have published 5197 blog posts posts and have received 4,369,422 hits altogether; I get an average of just under 1000 per day. This varies in a very erratic fashion from day to day, but there has been a bit of a downward trend over the last few years, presumably because I’m getting older and more boring. The largest number of hits I have received in a single day is 8,864 (at the peak of the BICEP2 controversy).

There have been 35,313 comments published on here and 2,672,823 rejected by the spam filters. The vast majority of the rejected comments were from bots, but a small number have been removed for various violations, usually for abuse of some kind. And, yes, I do get to decide what is published: it is my blog!

While I am on the subject of comments, I’ll just repeat here the policy stated on the home page of this blog:

Feel free to comment on any of the posts on this blog but comments may be moderated; anonymous comments and any considered by me to be abusive will not be accepted. I do not necessarily endorse, support, sanction, encourage, verify or agree with the opinions or statements of any information or other content in the comments on this site and do not in any way guarantee their accuracy or reliability.

It does mean a lot to me to know that there are people who find my ramblings on this `shitty wordpress blog’ interesting enough to look at, or even read, and sometimes even to come back for more, so I’d like to take this opportunity to send my best wishes to all those who follow this blog and especially those who take the trouble to comment on it in such interesting and unpredictable ways!

The last twelve years have been eventful, to say the least, both personally and professionally. I started blogging not long after I’d moved into my house in Pontcanna, Cardiff. Since then I moved to Sussex, then back to Cardiff, and now to Ireland. More importantly we’ve seen the discovery of the Higgs Boson and gravitational waves, both of which resulted in Nobel Prizes, as did the studies of high-redshift supernovae. The Planck mission mission was launched, did its stuff, and came to a conclusion in this time too. Science has moved forward, even if there are many things in this world that seem to be going backwards.

New Publication at the Open Journal of Astrophysics!

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , on September 15, 2020 by telescoper

A day may come when I don’t write a blog post every time we publish a new paper in the Open Journal of Astrophysics, but it is not this day…

Today’s new publication is by Liliya Williams (of the University of Minnesota, Twin Cities) and David Zegeye of the University of Chicago and is entitled Two-component mass models of the lensing galaxy in the quadruply imaged supernova iPTF16geu.

Here is a screen grab of the overlay:

You can click on the image to make it larger should you wish to do so.

Incidentally, you may notice that Scholastica have added MathJax to the platform to render mathematical expressions in the abstract.

You can find the arXiv version of the paper here.

Today’s Big Astronomy Announcement

Posted in Astrohype, Cardiff, The Universe and Stuff with tags , , on September 14, 2020 by telescoper

Rumours have been circulating for a few days about a big astronomical discovery. Here is a video of the announcement:

Sorry, that’s the wrong video.

The actual announcement will take place live at 4pm BST here:

Until a few minutes ago I didn’t have a clue what this was about, but now I do…

Phone ship surprisingly detected in atmosphere of Venus (9)

If you would like to read more about this discovery then you can read the paper in Nature here. Several of the authors are former Cardiff colleagues, including first author Jane Greaves, as well as Annabel Cartwright and my former office mate Emily Drabek-Maunder. Congratulations to them on an exciting result!

P.S. Emily reminded me last night that I was present at the discussion with Jane that started this project, over four years ago. I remember them talking about phosphine but had no idea that it would lead to this!

New Publication at the Open Journal of Astrophysics!

Posted in OJAp Papers, Open Access, The Universe and Stuff with tags , , , , , , , , on September 10, 2020 by telescoper

Another new paper  has been published in the Open Journal of Astrophysics! This is another for the folder marked Cosmology and Nongalactic Astrophysics and is entitled Low-scatter galaxy cluster mass proxies for the eROSITA all-sky survey.

The authors of this paper are Dominique Eckert of the University of Geneva, Alexis Finoguenov (Helsinki), Vittorio Ghirardini (MPE Garching), Sebastian Grandis (LMU), Florian Käfer (MPE Garching), Jeremy Sanders (MPE Garching) and Miriam Ramos-Ceja (MPE Garching).

For those of you unfamiliar with eROSITA, it is an X-ray instrument that was built at the Max Planck Institute for Extraterrestrial Physics, where several of the authors work.

Here is a screen grab of the overlay:

You can click on the image to make it larger should you wish to do so.

You can find the arXiv version of the paper here.

R.I.P. Govind Swarup (1929-2020)

Posted in The Universe and Stuff with tags , , , on September 8, 2020 by telescoper

This morning I learnt the sad news of the passing of Professor Govind Swarup who died yesterday at the age of 91. Govind Swarup was a pioneer in radio astronomy, especially in India, and in particular was a driving force behind the construction of the Giant Metrewave Radio Telescope, and the establishment of a world-leading radioastronomy group, which is located about 80km North of Pune in Maharashtra. I remember meeting with him a couple of times during visits to Pune and was struck by his friendliness and unbounded enthusiasm for astrophysics.

I send my condolences to his family, friends and colleagues in India who I know will miss him enormously.

R. I. P. Govind Swarup (1929-2020).

Littlewood on `the real point’ of lectures

Posted in Education, mathematics, The Universe and Stuff with tags , , , on September 3, 2020 by telescoper

We’re often challenged these days to defend the educational value of the lecture as opposed to other forms of delivery, especially with the restrictions on large lectures imposed by Covid-19. But this is not a new debate. The mathematician J.E. Littlewood felt necessary to defend the lecture as a medium of instruction (in the context of advanced mathematics) way back in 1926 in the Introduction to his book The Elements of the Theory of Real Functions.

(as quoted by G. Temple in his Inaugural Lecture as Sedleian Professor of Natural Philosophy at the University of Oxford in 1954 “The Classic and Romantic in Natural Philosophy”.)

Temple concluded his lecture with:

Classic perfection should be reserved for the monograph: the successful lecture is almost inevitably a romantic adventure. It is at once the grandeur and misery of a scientific classic that it says the last word: it is the charm of a scientific romance that it utters the first word, and thus opens the windows on a new world.

Modern textbooks do try to be more user-friendly than perhaps they were in Littlewood’s day, and they aren’t always “complete and accurate” either, but I think Littlewood is right in pointing out that they do often hide `the real point’ so students sometimes can’t see the wood for the trees. The value of lectures is not in trying to deliver masses of detail but to point out the important bits.

It seems apt to mention that the things I remember best from my undergraduate lectures at Cambridge are not what’s in my lecture notes – most of which I still have, incidentally – but some of the asides made by the lectures. In particular I remember Peter Scheuer who taught Electrodynamics & Relativity talking about his first experience of radio astronomy. He didn’t like electronics at all and wasn’t sure radio astronomy was for him, but someone – possibly Martin Ryle – reassured him by saying “All you need to know in order to do this is Ohm’s Law. But you need to know it bloody well.”