Monthly Archives: October 2011

Faster than light and the public misunderstanding of science

Yesterday evening, I gave a public lecture in Dublin on the Gran Sasso neutrino experiment, hosted by the Irish Skeptics Society. The event formed part of Maths Week Ireland, an initiative co-ordinated by CALMAST, the science outreach group at our college. We had a great audience turnout and I enjoyed the Q&A afterwards immensely. Below is the abstract and you can find the slides for the talk here.

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In September 2011, a group of scientists announced that they had detected subatomic particles travelling at speeds greater than the speed of light in vacuum. The finding is in conflict with Einstein’s theory of relativity and has been met with great skepticism by mathematicians and physicists around the world. This lecture will examine the grounds for that skepticism and consider the role of skepticism in general in science and mathematics

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       The Gran Sasso experiment

I suspect I was invited to speak because of a letter I had published on the subject in The Irish Times (below). Although the Gran Sasso experiment has certainly raised awareness of physics, I think the way the media are portraying this experiment as an  ‘Einstein wrong’ story is most unfortunate. It is far too soon to reach that conclusion and the overall effect is to make science seem very uncertain. It is more Public Misunderstanding of Science than PUS, in my view.

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Sir, – Margaret Moore (September 29th) asks what word will be used to describe a speed faster than the speed of light. The technical term is superluminal speed. However, much of the media coverage of recent experiments at Gran Sasso has been very misleading. Almost all professional physicists (including the experimenters) consider the Gran Sasso result a curious anomaly almost certainly due to some unknown error in measurement, for several reasons:

1. Light is carried by particles of zero mass and it follows that there are fundamental theoretical reasons for supposing that the speed of light in vacuum represents a natural speed limit for particles of non-zero mass.

2. Thousands of experiments have verified that the tiniest particles of matter can be accelerated up to speeds close to, but not equal to, this limiting speed.

3. The recent Gran Sasso experiment involves measurements of time and distance of unprecedented precision, yet it was not designed for this specific purpose; thus there are many potential sources of systematic error.

It’s true that science sometimes progresses by upsetting the status quo, but scientists are a sceptical lot and extraordinary claims require extraordinary evidence! –Yours, etc,

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Does it matter how the experiment has been portrayed in the media? I think it does. A few years from now, journalists will be say ‘ but didn’t you guys think in 2011 that Einstein was wrong’? In fact, there has already been one editorial in the Wall St Journal urging inaction on climate change, on the basis that science is never certain, given the neutrino result (see point 5 of this article ). Exactly the wrong conclusion to draw…

Update

I see my lecture got a short review in today’s Irish Times. It’s not a bad overview, considering the writer wasn’t at the lecture. The last sentence doesn’t make sense, however – I suspect she meant supernovae instead of black holes!

Udate II

Just caught  BBC program on the experiment (Marcus du Sautoy). Superb, superb program. Nothing like the players themselves for conveying the concepts of science..

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Hamilton Walk and Maths Week in Ireland

October 16th is a special day for mathematics and physics in Ireland. On this day, we commemorate the discovery of quaternions by William Rowan Hamilton, the great Irish mathematician and astronomer. Essentially, his insight was to postulate three distinct roots for the number -1, thus generalising complex numbers to four dimensions. It can be said that this discovery marks the birth of modern algebra, as quarternions opened the door to non-commutable algebra. Quaternions have found great application in modern technology, notably in compter algorithims for animation in films and computer games.

William Rowan Hamilton made a great many other contributions to mathematics and physics. For example, his formulation of a mathematical operator for the energy of a body – the Hamiltonian –  is a vital tool in quantum mechanics, the mathematical description of the quantum world. Open any modern textbook on quantum physics and you will encounter the word ‘Hamiltionian’ on almost every page.

As regards quaternions, we know exactly when Hamilton had his Eureka moment. According to his own writing, inspiration struck on the 16th october in 1843,  as he was walking with his wife from Dunsink Observatory in County Dublin (where he was Astronomer Royal) along the Royal Canal towards the city centre, in order to attend a meeting of the Royal Irish Academy, of which he was President.  He was so pleased with the breakthrough that he used his penknife to carve the new equation onto Broom bridge as they passed. The carving no longer exists but the bridge does, and the occasion is celebrated with a plaque. Every year, mathematicians and friends of mathematics congregate at Dunsink Observatory at 3pm and re-enact Hamilton’s famous walk along the canal to the bridge.

  

William Rowan Hamilton; the plaque displays the famous equation i2 = j2 = k2 = ijk = -1

This year, October 16th fell on a Sunday, so mathematicians and the general public arrived from far and near. The day started in Dunsink Observatory, with a brief description of Hamilton’s life and work by Fiacre O Cairbre, event organiser and lecturer in mathematics at NUI Maynooth. There followed a lovely walk along the canal in perfect weather conditions, all the way to Broom bridge to view the plaque. The outing finished with a short description of Hamilton’s breakthrough by another Maynooth mathematician, Anthony O’ Farrell, and a chorus of ‘Happy birthday, quaternions’ by all present. I think it’s great to remember our scientific heros like this;  it’s curious that even our very best scientists and mathematicians receive far less public attention that writers and musicians.

 

Dunsink Observatory and Broom Bridge on the Royal Canal

Each year, the Hamilton Walk is soon followed by a prestigious lecture on mathematics presented by the Royal Irish Academy and The Irish Times. Previous speakers have included Andrew Wiles, Steven Weinberg, Murray Gellman and Lisa Randall. This year, renowned string theorist Ed Witten will give a talk on quantum knots, see here.

The Hamilton walk  is one of the core activies of Maths Week Ireland, an initiative to raise awareness of maths in Ireland with events and lectures all around the country. Co-ordinated by CALMAST, a science outreach group at Waterford Institute of Technology, Maths Week has grown larger every year – you can find the program of events here. I will give a talk in Dublin on Wednesday evening, on relativity and the recent ‘faster than the speed of light’ experiment, see here .

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Tyndall conference in Ireland

This weekend, I caught the last day of a climate conference honouring the memory of the great Irish scientist John Tyndall. Born in County Carlow, Tyndall became a key member of the Royal Society around the time of Charles Darwin. He studied under Robert Bunsen in Germany and did much to promote the idea of experimentation in science. Among his many contributions are the discovery of the Tyndall effect (an explanation for the colour of the sky in terms of the scattering of light) and pioneering works in optics.

Tyndall’s most important contribution was his experimental demonstration of the greenhouse effect. He was the first to show that certain gases – notably carbon dioxide and water vapour – absorb radiation of infra-red wavelength, thus trapping heat reflected from the earth. This discovery forms the bedrock of the modern climate science. Today’s phenomenon of global warming (measured as an increase in global temperature, glacier-melt and sea level rise over the last few decades) has been attributed to an increased concentration of greenhouse gases in the atmosphere caused by the burning of fossil fuels.


The 2011 Tyndall climate conference was sponsored by the EPA and the Royal Irish Academy

The conference celebrated the 150th anniversary of the publication of Tyndall’s landmark paper On the Absorption and Radiation of Heat by Gases and Vapours and took place in Dublin castle, a superb venue in the heart of Dublin’s vibrant city center (and the seat of British rule in Ireland only a century ago). Day one was an overview of Tyndall’s life and work, with a keynote lecture by eminent climatologist Richard Sommerville. The next two days featured slightly more technical talks on climate science. You can find the conference program and book of abstracts here.

I caught several excellent talks on Friday, including a talk on climate sensitivity and feedback mechanisms by John Mitchell of the UK Hadley Centre, and a talk on tipping points and their predictability by Peter Ditlevensen of the Center for Ice and Climate at the Niels Bohr Institute in Copenhagen. Another talk, by George Moore of the University of Toronto, suggested that we may already have passed such a tipping point. The lecture  ’20 years of IPCC projections’ by Ulrich Cubasch of the Free University of Berlin, demonstrated how well IPCC projections have stood the test of time. This is a point often overlooked in discussions of climate science in the media. The public are wary of theoretical models, and climate scientists sometimes forget to point out that we have had twenty years to test predictions – so far, the projections have turned out to be all too accurate.

Possibly the most advanced talk of the day was by Professor Ray Bates of the Meteorology and Climate Centre at University College Dublin, a former professor of meteorology at the Neils Bohr Institute. In his talk, Ray presented a new global climate model, contrasting it with the recent model of Dick Lindzen. The Lindzen model is quite controversial as it suggests that conventional climate models overestimate the contribution of an enhanced greenhouse effect on climate. In good scientific fashion, Ray outlined the basic physics underpinning the two models, steering clear of polemics and concentrating on the science. You can Ray’s paper on his, and other, models here .

All in all, a great conference, I was sorry to miss the first two days. One of the aspects the increased teaching workload in the Institute of Technology sector is that there is almost no time left over for conferences – someone’s idea of increased productivity.

Update

Richard Sommerville did a very nice interview on the Pat Kenny show, a flagship radio show on RTE radio 1. Pat raised almost every point favoured by climate skeptics, while Richard provided clear and cogent answers to each. Well worth a listen, you can download a podcast here.

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