Monthly Archives: May 2011

Gravity probe B experiment does not ‘prove Einstein right’

A good example of the problems of science journalism we discussed in the last post can be seen in this month’s media treatment of the important results from the NASA Satellite Gravity Probe B. After many years of frustration, the experiment has reported important evidence in support of two distinct predictions of the general theory of relativity – the geodesic effect (a distortion of spacetime by the earth) and frame dragging (caused by the rotation of the earth). See here for details of the experiment.

The result is a fantastic achievement. It offers important support for general relativity, a theory that underpins a great deal of modern physics, from our view of the origin of the universe to our understanding of black holes. It’s worth noting that such tests are rare and notoriously difficult (unlike the case of special relativity) and sincere congratulations are due to Principal Investigator Francis Everitt and all the team who worked so hard and so long to produce this important result.

The NASA Gravity Probe B Satellite

However, I was quite disappointed at the way the result was portrayed in newspapers and in science magazines. Almost without exception, the experiment was described as  ‘Einstein proven right‘ – see for example this article in the prestigious journal Science.

What’s the problem? The statement ‘Einstein proven right’ is deeply problematic for two reasons
1. As Einstein (and later Karl Popper) frequently pointed out, it is a basic tenet of the scientific method that no experiment can ‘prove’ a theory right. An experiment can offer supporting evidence but the case is never closed, because we do not know what new evidence may emerge in the future to cast doubt on other predictions of the theory
2. The constant personalization of the theory of relativity with Einstein creates the impression that the theory depends upon one scientist only, and devalues the work of hundreds of relativists since.
For the above two reasons, most physicists would have framed the result as ‘general relativity passes two important tests’.

It seems to me that such shorthand reportage does science no favours, as it misrepresents the result and plays into the hands of doubters and anti-science commentators. I wrote to Science to make this point; they have declined to publish my letter, so I am free to reproduce it here

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Re: At Long Last, Gravity Probe B Satellite Proves Einstein Right

News Section, Science, May 5

As a physicist and a science writer, I was surprised by your headline ‘At Long Last, Gravity Probe B Satellite Proves Einstein Right’ (News Section, Science, May 5).

To be sure, the Gravity Probe B experiment is a fantastic achievement that offers spectacular evidence in support of two distinct predictions of the general theory of relativity. This is important support for a theory that underpins a great deal of modern physics, from our view of the origin of the universe to our understanding of black holes. It’s also worth noting that such tests are rare and notoriously difficult (unlike the case of special relativity) and sincere congratulations are due to the team who worked so hard and so long to produce this important result.

However, your headline is problematic for anyone with a knowledge of the scientific method or an interest in the philosophy of science.

In the first instance, it is a fundamental tenet of science that no experiment can ‘prove a theory right’, as Einstein himself (and Karl Popper) frequently acknowledged. Even the most ingenious experiment can only offer evidence in support of a theory –‘right so far’ (and this is leaving aside the difficult question of the interpretation of scientific data). The error is not simply a question of headline shorthand as it is repeated in the opening sentence of the article;  ‘..a ..NASA spacecraft has confirmed general relativity’.

Second, it is a pity that relativity is so often portrayed as the work of one great scientist. Granted, it is a matter of historical record that the general theory of relativity was first formulated by Einstein singlehandedly. However, a great many mathematicians and theoretical physicists have explored, deepened and refined the theory since that time (obtaining solutions to the field equations and deriving concrete predictions from these solutions, for example). Framing the story in terms of Einstein alone ignores this work, and implies that the entire edifice of relativity is dependent upon one scientist.

In sum, it is no easy task to summarize a groundbreaking scientific experiment in a brief article, but most physicists would frame this important result as ‘general relativity passes another experimental test’ rather than ‘Einstein proven right’.

Yours sincerely

Dr Cormac O’Raifeartaigh

Visiting Fellow, Program on Science, Technology and Society, Harvard Kennedy School

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Refuting Einstein: a media controversy in Ireland

I had a very sobering conversation about science communication with an eminent climate scientist at MIT yesterday, and it got me thinking about the incident that first prompted my interest in writing science for a wide audience.

In the late 1990s, I had just returned from a postdoctoral research position at the University of Aarhus in Denmark, and was embarking on a similar stint at Trinity College Dublin. After all that training, I had the smug feeling that I was finally evolving into a scientist; and right at that moment, a scientific ‘controversy’ broke in the British and Irish media. A distinguished Irish engineer, Dr Al Kelly , published a number of papers that claimed to show that Einstein’s special theory of relativity (SR) was fundamentally unsound, work that received a great deal of media attention. I was intrigued by the story and set about getting my hands on the publications.

Dr Al Kelly, a highly respected engineer

The first surprise was that the papers were not published in a well-known peer reviewed journal, but in the monthly Journal of the Institute of Irish Engineers. This is a respectable magazine (now known as The Engineers Journal), but not a natural forum for technical papers on fundamental physics – yet the work had already received far more media attention than any other physics research in Ireland. [Dr Kelly himself complained publicly that the more established journals refused to consider his papers on special relativity on point of principle! A great many journals do in fact refuse to consider papers on SR, simply because the subject is such a favourite target of cranks and skeptics with little scientific training].

The second surprise was that, on reading the Kelly papers, it seemed to me that the author did not have a good understanding of the basic theory of SR (for example, his definition of an inertial frame seemed strange). In addition, there was no reference to the vast amount of experimental evidence supporting the key predictions of SR – time dilation, mass increase and the universality of the speed of light in vacuum (routinely observed in particle accelerators around the world). Instead, the author attempted a refutation of SR on the basis of the  Sagnac effect, a complicated effect that pertains to rotating bodies.

The Sagnac effect: coherent light travels around a rotating loop in opposite directions and the phases of the two signals are compared at a detector

Now, an effect concerning rotating bodies is not where one would normally start with a refutation of special relativity, because a rotating body is accelerating while SR pertains to inertial frames i.e. frames moving at constant velocity relative to one another. An additional problem is that the two light beams do not in fact travel the same distance relative to an observer in the centre of the frame (see reference above). A proper relativistic treatment of the Sagnac effect is quite complicated, and involves terms from General Relativity, the theory of relativity that deals with accelerating bodies. Most importantly of all, relativistic effects do not show up as first- or second-order effects in the Sagnac effect, making it an unsuitable effect for experimental tests of relativity.

Media reaction

It was not the work itself that shocked me. Any physicist regularly receives refutations of SR in the post, ranging from the completely crazy to the highly aggressive. What shocked me was the media reaction to Kelly’s work; the story immediately became a media ‘controversy’, with feature articles in The Irish Times (Ireland’ s paper of record), the Sunday Times (a respected UK paper), the Japan Times and many others. There were regular bulletins on TV and radio, with few journalists treating the story with even a small degree of skepticism. The internet also played a role in the affair, with hundreds of blogposts by writers who knew nothing about the subject. (It put a great many Irish physicists off blogs for life). The Irish Times set the tone for the affair by using the headline ‘Refuting Einstein’ for all articles and letters on the subject, thus framing the debate as plucky Kelly vs establishment Einstein.

Professional physicists paid very little attention to the story at first. In the few instances where their opinion was sought, the ‘debate’ was portrayed as one voice against another, not as the overwhelming consensus of 100 years of scientific evidence against one engineer. Most of all, the debate was portrayed as Kelly vs Einstein – I do not recall a single journalist draw attention to the fact that physicists’ belief in relativity stems not from a belief in Einstein, but from the mountain of experimental evidence that supports the theory (a confusion of the context of discovery with the context of justification). Finally, just as the story was beginning to die down, a French physicist cited one of Kelly’s papers and Irish journalists declared Kelly ‘vindicated’. [I read the French paper and the reference was not to Kelly's theory at all, but to an experiment he suggested].

Not long after all this, Al Kelly sadly passed away. I should stress that he was a very nice man and an accomplished engineer. His papers on the subject were published posthumously as a book, which is available on Amazon.

Lessons

You rarely see a reference to the Kelly debate nowadays, but I learnt several things from the incident

1. In the eyes of science journalism, ‘Einstein wrong’ constituted a story. None of the journalists I contacted privately expressed any confidence in Kelly’s theory, but they thought it was an ‘interesting story and a good way of raising science awareness’.

2. In the few instances where professional opinion was sought, a ‘balanced’ media debate was achieved by pitting one voice against another, with no mention of scientific consensus

3. The reaction of the public was firmly anti-science. The affair dominated the letters page of The Irish Times for months and the general tone of the letters was a distrust of the establishment. All sorts of people jumped to defend the plucky Kelly, while the professionals were accused of ‘believing in relativity like a religion’.

Science journalism

All in all, the affair left me with a very skeptical view of science in the media, a view which has not changed much over the years. It seems to me that there are several problems in science journalism that are rarely aired;

- motivation: the primary motivation of a journalist is to get the story, not the truth; a difference of opinion v quickly becomes a ‘controversy’

- expert opinion: journalists can be quite hazy on what constitutes expert opinion; the Kelly story would only have been controversial if he was a Professor of relativity (or even a physicist)

- scientific knowledge: journalists often have quite a low level of understanding of the science in question, and even of the scientific method. In particular, a great many journalists fail to grasp the difference between discovery (initial theory etc) and justification (evidence)

- scientific consensus: this remains a mystery to many journalists; how it is achieved and why it is important yet never unaminous

As a result, I have become convinced that there is a need a new sort of science journalism – science communicated by scientists, not by journalists. Of course it is difficult to train scientists to write in a manner suitable for public consumption, but I suspect this is less difficult than training journalists to think like scientists. From debates on global warming to alternative medicine, there is an urgent need for scientists to be trained to speak for themselves.

A neutral debate

The one good thing about the ‘controversy’ above is that it was a neutral debate – neither business nor politics had a stake in the outcome, nor was there a prospect of Joe Citizen paying extra at the pump. This is not the case in areas such as climate science, which makes media coverage of the topic a great deal more complicated. All of the above concerns apply to media coverage of climate change – but in addition, much climate science in the media consists of op-eds by writers whose motivations are complex and whose portrayal of the subject is highly questionable. We’ll look at the communication of climate science in the next post.

Postscript

I just found a copy of my own letter to The Irish Times on the controversy above; my first media publication on science! It is co-authored with astrophysicist Lorraine Hanlon, now Head of Physics at UCD.

Update

The writer John Farrell, who wrote a very nice biography of Lemaitre, has a good article  on relativity cranks on the Salon website here.

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