Monthly Archives: April 2009

Astronomy Ireland and IYA

Last Saturday, Astronomy Ireland hosted an extraordinary national meeting at the Science Gallery at Trinity College Dublin, in order to draw members’ attention to planned events to mark the UN International Year of Astronomy.

Astronomy Ireland (AI) is Ireland’s premier astronomy club and it promotes astronomy, space interest and science education all over the country. I first became aware of the club when I attended some great cosmology talks they hosted last year (see post on a lecture onThe Cosmological Distance Ladder by Micheal Rowan-Robinson here and on Dark Matter by Tim Sumner here); AI also organise observing sessions and other astronomy events nationwide, not to mention running astronomy classes in various institutions around the country. I attended their astronomy classes in our own college this semester and found them excellent (well done Emmet Mordaunt!).

Saturday’s meeting offered a packed program of talks, short films and discussions. First up was film producer and director Ginita Jimenez of film company Father Films, who described how she came to make a short film about Venetia Phair, the 11-year old Oxford schoolgirl who named the planet Pluto. I missed the beginning of Ginita’s talk, but her description of reading a short newspaper article on the topic and her subsequent discovery that Venetia had never actually seen the planet, was fascinating: with the demotion of Pluto to ‘dwarf planet’ status, she knew she had to make a film about the whole affair.

After Ginita’s introduction, we were treated to the Irish premiere of ‘Naming Pluto’. Sure enough, it was a beautiful little film: the discovery of a new planet from the perturbations in the orbit of Uranus, the naming of the planet by Venetia, granddaughter of Falconer Madan, ex-Head of Oxford University’s Bodleian Library, the subsequent passing of the name to the powers that be in Flagstaff USA, it was all there. (I’m not sure how many of our students would have 11-year old Venetia’s knowledge of both astronomy and classical mythology – planets are generally named after Roman gods and Venetia suggested Pluto as he is the Roman god of the underworld). The second part of the film described an older Venetia’s visit to uber-astronomer Patrick Moore, a failed sighting, and then her first sighting of the planet she named all those years ago at the Science Observatory in Hertsmonceaux at age 89. The film finished with some moving shots of an aged Venetia telling her story to a group of wide-eyed students – straight out of C.S. Lewis, you could see them trying to imagine her as an 11-year old! If you want to know more, there is a summary of the story here and a nice trailer of the film on YouTube here; better still, why don’t you buy the film here.  

Robert Hill of the Armagh Planetarium and Northern Ireland Space Office then gave a lively overview of activities worldwide that are taking place to mark the International Year of Astronomy. The sort of activities involved are:

100 hours of astronomy: a round-the-clock event that features live webcasts from research observatories around the world

The Galileoscope ; the distribution of thousands of easy-to-assemble, easy-to-use telescopes to budding astronomers around the world: each telescope has about the same power as that available to Galileo

Cosmic Diary: an astronomy blog featuring regular posts by diverse professional astronomers

Portal to the universe; a one-stop web portal for astronomy that will feature astronomy content, acting as an index for press, educators and scientists

Dark Skies Awareness: a project promoting the awareness of light pollution

It was a great talk and you can find out more about the various activites on the IYA website.

AI founder and chairman David Moore also gave a talk, describing the activites of Astronomy Ireland for the year that’s in it, in particular the school lecture program and the teacher training program. He also described what individual members could do, from voluntary work to lobbying public representatives. A change of mission was highlighted: instead of confining itself to promoting astronomy, David sees AI as promoting a science culture in Ireland. He pointed out that while Ireland has a great culture in both arts and sports, it has no such culture in science, despite a great heritage in the subject. I think he is absolutely right in this and it strikes me that astronomy is a very good place to start to address the can find a list of the planned AI activities here or on the AI website.

David Moore (R) in interview at the Young Scientist Exhibition

After David’s talk, we were treated to another short film. 3-d glasses were handed out and Robert Hill presented a short spectroscopic tour of the universe. I won’t attempt to summarize the film, but there were some stunning graphics. You can get a flavour of it by taking the tour on the website of Celestia. As usual, I came away thinking just how insignificant our own little galaxy is in the wider scheme of things.

All in all, the meeting was a lively and informative event, with a serious mission behind it. Afterwards, we left the beautiful Science Gallery for some hot food and drinks at the pub across the road (it was an Irish meeting after all). There, discussions on the promotion of science continued for many hours…


I just heard from Ginita that Venetia died last week at the age of 90. Sad news, but I’m sure she enjoyed seeing the film in her final days. You can find a nice NYT obituary here. Ar dheis De do raibh a h-anam


Filed under Astronomy

Binary black holes, gravitational waves and numerical relativity

We had an excellent turn-out for yesterday’s superb Institute of Physics seminar even though we are in the last hectic week of the teaching semester (thanks to the organisational skills of the WIT maths/physics seminar group). The talk ‘Binary black holes, gravitational waves and numerical relativity’ was given by Dr Joan Centrella, head of the Gravitational Astrophysics Laboratory at NASA’s Goddard Space Flight Centre. Dr Centrella is a distinguished relativist, well known for her work in the simulation of black hole mergers and she certainly didn’t disappoint.

The lecture started with an overview of massive black holes, intermediate black holes and gravitational waves. Just as general relativity predicts that a large mass will curve spacetime, it predicts that moving mass will cause ripples in the curvature of spacetime – known as gravitational waves. Of course, such disturbances will be extremely difficult to detect due to the weakness of the gravitational interaction. Indeed, while many of the spectacular predictions of general relativity have been verified (the bending of light in a gravitational field, time dilation in a gravitational field, black holes and even the expanding universe) the direct detection of gravitational waves is possibly the last great test of relativity. The speaker explained that the best chance of seeing the phenomenon directly is by studying the most explosive events known: black hole mergers.

There was a brief description of the indirect observation of gravitational waves, in particular the Hulse-Taylor pulsar. This is a binary pulsar found in 1974, whose orbit has been observed to be gradually shrinking due to the radiation of energy by gravitational waves: the two stars will merge in about 300 million years. Interesting that Hulse got the Nobel for work done while still a postgraduate, while Jocelyn Bell was overlooked for her discovery of pulsars – see post on IoP meeting below.

Centrella then gave an overview of direct searches for gravitational waves, both earth-bound (LIGO) and space-based (LISA). LIGO, the Large Interferometer Gravitational Wave Observatory, is basically a huge Michelson interferometer, complete with laser source, beam splitter and mirrors – the arms of the interferometer are several kilometers in length! LISA, the Laser Interferometer Space Antenna, is an astounding project: a joint NASA/ESA mission, it will consist of three separate mini-spacecraft, each with its own laser source, maintained in an equilateral triangle that will form a giant Michelson interferometer in space. Minute disturbances in spacetime by a passing gravitational wave will be measured as tiny changes in relative arm length (having taken all other factors into account). A crucial difference between the two systems is the target: while LIGO searches for intermediate black hole events, LISA will search for massive BH events (a much stronger source in a different region of the spectrum).

LIGO (California)

LISA (artist’s impression)

Dr Centrella then described her own field: the use of numerical methods and algorithims to solve the equations of general relativity for the particular case of relativistic binary systems and their associated gravitational waves. She gave a great overview of historic problems in the area and recent breakthroughs in the field, from the puncture method to the Lazarus approach. I won’t attempt to summarize this part of the talk, but there is a nice overview of the field here and I should have a link to the slides from the talk in a day or two.

Dr Centrella with a scale model of one of the LISA spacecraft

All in all, this was a superb lecture, courtesy of the Institute of Physics. It was clear the audience enjoyed the lecture thoroughly and there were plenty of queries at question time – indeed the lecture would have continued for another hour had we not whisked the speaker off for dinner. In answer to my own question on the detection of gravitational waves from the Big Bang itself, Dr Centrella pointed out that one would certainly to see expect a signal from cosmic inflation – however these waves would be in a very different region of the spectrum from that studied by either LIGO or LISA. ..

Update: Joan has been in contact to say you can get a review article she wrote on the subject for the Scidac Review here; she has also done a podcast for Sky and Telescope with movies of the simulations here. She also has two comments and corrections to the text above; rather than paraphrase them I have put them verbatim in the comments section!

Update II: there is a wonderful article on gravitational waves and the early universe by Craig Hogan in the June 2007 edition of Physics World, which you can access here if you’re a member


Filed under Cosmology (general)

Back in Switzerland

This week I’m back in Switzerland; in fact I’ve been here a bit more than a week and am not leaving until Sunday. I figured I’d be in need of a good holiday after a busy term and the Institute of Physics Spring Meeting (see previous post) so I booked myself 10 days skiing in Zermatt, the famous little town just below the Matterhorn.

The Matterhorn

On piste at the Klein Horn

The snow is fine both on- and off-piste, if a bit icy in the mornings and a bit slushy in the afternoons (I quite like variable conditions).The Ski Club of Great Britain are here in force with two different reps and I’ve been doing plenty of skiing with them on off-piste days. Such a joy to ski with experienced skiers, thanks Alaistair and Chris! (For ski bores out there: I’m trying the K2 Public Enemy twin-tip skis and find them superb for the variable snow, although the plume they kick up in spring snow drives some people nuts). I like the way free-ride technology can work it’s way into the mainstream…

Off-piste at the Stockhorn

Zermatt itself is drop-dead gorgeous, the archetypal Swiss ski resort, with superb restaurants, no cars and unbelievable views. Did I mention the world’s best apres-ski, rockin to an outdoor live band in the serious sun half way up the Matterhorn?

Zermatt Hauptstasse


It snowed all night on Wednesday. Snow conditions were excellent on Thursday, but visibility was poor.  Today, the sun came out and the conditions were fantastic. Best powder I’ve ever experienced, particularly off-piste. In fact possibly the best skiing I’ve ever had, despite witnessing the best skier of our group take a serious tumble on hidden ice off-piste at Stockhorn – no less than six somersaults on the way to the bottom. Happily, no serious injury resulted…photos to follow!

More ski cronies are arriving late tonight – the Frankfurt Ski Club are due in at midnight on their ski bus (if past trips are anything to go by, most of them will be hammered before they even get off the bus). I have some very good friends in this club; although the actual skiing can be a bit chaotic due to varying levels, the craic is mighty.The Frankfurters are staying until Monday, but yours truly has to finally return to Ireland on Sunday. Ah well, I expect some serious partying on Saturday, my last night in Zer…

And then it’s back to a hysterical week at WIT. The last week of term for the students (and all that entails) + Prof Joan Centrella of NASA’s Goddard Space Centre is giving a talk on Black Hole formation and gravitational waves on Wednesday + Peter Woit of NOT EVEN WRONG is arriving in Ireland on Friday. Jesus. I need a beer…


Filed under Skiing

Institute of Physics Spring Weekend

This weekend I was at the annual spring meeting of the Institute of Physics in Ireland in Wexford. I always enjoy these weekends – more relaxing than a technical conference and a great way of keeping in touch with physicists from all over Ireland. As ever, there were good seminars, a physics pub quiz and discussions of science and philosophy over breakfast, lunch and dinner (not to mention a 32-strong Wexford choir who gave superb after-dinner entertainment). At the same time, there was a serious side to the weekend with committee meetings, the Annual General Meeting and a highly competitive poster competition for postgraduates.

The theme of the seminars on Saturday was ‘Physics for Life’ and it mainly concerned advances in medicine/ biology that have resulted from research in fundamental areas of physics such as atomic and molecular physics (Bob McCullough of Queen’s University Belfast), solar physics (Louise Harra of University College London), nano-photonics (Brian MCraith of DCU) and molecule manipulation using ‘optical tweezers’ (Martin Hegner from Trinity). I won’t attempt to describe each talk, but you can find abstracts of the talks here.

My favourite was a general talk on causality in complex systems by world-famous cosmologist George Ellis: ‘Top-down action in the hierarchy of complexity’. This was a fascinating overview of the subject of causation, focusing on the influence of feedback from top-down processes on bottom-up causes. There were lots of great examples and the speaker was fully convincing in his conclusion that ‘no complex system can have a single cause’. I couldn’t help thinking how true this is of climate change. Some media pundits describe global warming phenomenon in terms that too simple; by citing man-made CO2 as the only factor in climate, they give great ammunition to climate skeptics who point to other factors. (The point is that while CO2 is not the only factor in global climate, it is now clear that the man-made increase in CO2 is a significant driver of warming.)


Top-down causality: George Ellis

Sunday saw a new IoP initiative – instead of more seminars, four well-known physicists were given the ‘This is your Life’ treatment in sequence. It was a great success, with the legendary Tony Scott of UCD interviewing Ronan Mc Nulty (on the LHCb experiment), Sile McCormaic (on her path to the world of cold atoms) and Ray Bates (reknowned Irish climatologist who was one of the first in the area of climate modelling).

Best of all, the very first interviewee was Dame Jocelyn Bell-Burnell, the Belfast-born astrophysicist famed for her discovery of radio pulsars. (She is also President of the Institute of Physics). Professor Bell gave a fascinating overview of her life in physics, from failing the 11-plus exam to Cambridge. Of particular interest was her description of the postgraduate work leading up to the famous discovery: the long build of the radio-telescope from raw materials, perservering to the end as team members drifted off, the discovery of an unknown source, convincing her supervisor she was onto something, the disappearance of the source and the stress of a possible mistake and lost thesis, the re-appearance of the source, the classification of the first pulsars….terrific stuff.


Tony Scott interviewing Jocelyn Bell-Burnell

Professor Bell’s story was reminiscent of the discovery of the microwave background by Penzias and Wilson (see post here), but with one big difference. Bell was a highly trained astrophysicist, who understood clearly that she might have discovered an important phenomenon. For this reason, it is still highly controversial that, while her supervisor Antony Hewish was awarded the Nobel prize for this work, she was not. Was it because she was still a postgraduate? Because she was a woman? Perhaps we will never know. Apparently, there was a very good BBC documentary on the story a few months ago – I misssed it but I’ll try and track it down.

As always, the most humbling part of the weekend was the postgraduate posters. The level of research made one feel seriously inadequate. You can find the results of the competition on the IoP website; choosing the winners must have been very difficult. I particularly enjoyed two posters from UCD on the LHCb experiment (an indirect measurement of luminosity using muon production rates, and the measurement the cross-section of Z boson -muon decay). Even there, Ronan had to explain to me how antiquarks arise in proton-proton collision; must revise my quark physics!


Poster session at the meeting

All in all, a super weekend, courtesy of the Institute of Physics. Now it’s back to earth and those corrections…


Filed under Institute of Physics, Teaching, Uncategorized