Archive for Cosmology

The MacGuffin Factor

Posted in Science Politics, The Universe and Stuff with tags , , , on September 22, 2008 by telescoper

Unpick the plot of any thriller or suspense movie and the chances are that somewhere within it you will find lurking at least one MacGuffin. This might be a tangible thing, such the eponymous sculpture of a Falcon in the archetypal noir classic The Maltese Falcon or it may be rather nebulous, like the “top secret plans” in Hitchcock’s The Thirty Nine Steps. Its true character may be never fully revealed, such as in the case of the glowing contents of the briefcase in Pulp Fiction , which is a classic example of the “undisclosed object” type of MacGuffin. Or it may be scarily obvious, like a doomsday machine or some other “Big Dumb Object” you might find in a science fiction thriller. It may even not be a real thing at all. It could be an event or an idea or even something that doesn’t exist in any real sense at all, such the fictitious decoy character George Kaplan in North by Northwest.

Whatever it is or is not, the MacGuffin is responsible for kick-starting the plot. It makes the characters embark upon the course of action they take as the tale begins to unfold. This plot device was particularly beloved by Alfred Hitchcock (who was responsible for introducing the word to the film industry). Hitchcock was however always at pains to ensure that the MacGuffin never played as an important a role in the mind of the audience as it did for the protagonists. As the plot twists and turns – as it usually does in such films – and its own momentum carries the story forward, the importance of the MacGuffin tends to fade, and by the end we have often forgotten all about it. Hitchcock’s movies rarely bother to explain their MacGuffin(s) in much detail and they often confuse the issue even further by mixing genuine MacGuffins with mere red herrings.

North by North West is a fine example of a multi-MacGuffin movie. The centre of its convoluted plot involves espionage and the smuggling of what is only cursorily described as “government secrets”. But although this is behind the whole story, it is the emerging romance, accidental betrayal and frantic rescue involving the lead characters played by Cary Grant and Eve Marie Saint that really engages the characters and the audience as the film gathers pace. The MacGuffin is a trigger, but it soon fades into the background as other factors take over.

There’s nothing particular new about the idea of a MacGuffin. I suppose the ultimate example is the Holy Grail in the tales of King Arthur and the Knights of the Round Table and, much more recently, the Da Vinci Code. The original Grail itself is basically a peg on which to hang a series of otherwise disconnected stories. It is barely mentioned once each individual story has started and, of course, is never found.

Physicists are fond of describing things as “The Holy Grail” of their subject, such as the Higgs Boson or gravitational waves. This always seemed to me to be an unfortunate description, as the Grail quest consumed a huge amount of resources in a predictably fruitless hunt for something whose significance could be seen to be dubious at the outset.The MacGuffin Effect nevertheless continues to reveal itself in science, although in different forms to those found in Hollywood.

The Large Hadron Collider (LHC), switched on to the accompaniment of great fanfares last week, provides a nice example of how the MacGuffin actually works pretty much backwards in the world of Big Science. To the public, the LHC was built to detect the Higgs Boson, a hypothetical beastie introduced to account for the masses of other particles. If it exists the high-energy collisions engineered by LHC should reveal its presence. The Higgs Boson is thus the LHC’s own MacGuffin. Or at least it would be if it were really the reason why LHC has been built. In fact there are dozens of experiments at CERN and many of them have very different motivations from the quest for the Higgs.

Particle physicists are not daft, however, and they have realised that the public and, perhaps more importantly government funding agencies, need to have a really big hook to hang such a big bag of money on. Hence the emergence of the Higgs as a sort of master MacGuffin, concocted specifically for public consumption, which is much more effective politically than the plethora of mini-MacGuffins which, to be honest, would be a fairer description of the real state of affairs.

Even this MacGuffin has its problems, though. The Higgs mechanism is notoriously difficult to explain to the public, so some have resorted to a less specific but more misleading version: “The Big Bang”. As I’ve already griped, the LHC will never generate energies anything like the Big Bang did, so I don’t have any time for the language of the “Big Bang Machine”, even as a MacGuffin.

While particle physicists might pretend to be doing cosmology, we astrophysicists have to contend with MacGuffins of our own. One of the most important discoveries we have made about the Universe in the last decade is that its expansion seems to be accelerating. Since gravity usually tugs on things and makes them slow down, the only explanation that we’ve thought of for this perverse situation is that there is something out there in empty space that pushes rather than pulls. This has various possible names, but Dark Energy is probably the most popular, adding an appropriately noirish edge to this particular MacGuffin. It has even taken over in prominence from its much older relative, Dark Matter, although that one is still very much around.

We have very little idea what Dark Energy is, where it comes from, or how it relates to other forms of energy we are more familiar with, so observational astronomers have jumped in with various grandiose strategies to find out more about it. This has spawned a booming industry in survey of the distant Universe (such as the Dark Energy Survey) all aimed ostensibly at unravelling the mystery of the Dark Energy. It seems that to get any funding at all for cosmology these days you have to sprinkle the phrase “Dark Energy” liberally throughout your grant applications.

The old-fashioned “observational” way of doing astronomy – by looking at things hard enough until something exciting appears (which it does with surprising regularity) – has been replaced by a more “experimental” approach, more like that of the LHC. We can no longer do deep surveys of galaxies to find out what’s out there. We have to do it “to constrain models of Dark Energy”. This is just one example of the not necessarily positive influence that particle physics has had on astronomy in recent times and it has been criticised very forcefully by Simon White.

Whatever the motivation for doing these projects now, they will undoubtedly lead to new discoveries. But my own view is that there will never be a solution of the Dark Energy problem until it is understood much better at a conceptual level, and that will probably mean major revisions of our theories of both gravity and matter. I venture to speculate that in twenty years or so people will look back on the obsession with Dark Energy with some amusement, as our theoretical language will have moved on sufficiently to make it seem irrelevant.

But that’s how it goes with MacGuffins. Even the Maltese Falcon turned out to be a fake in the end.

p.s. I heard on Saturday that the LHC is having some problems with its magnets and will actually be off-line for a few months. Last week I heard a particle physicist describing the great switch-on as like “Christmas”. This turns out to have been truer than he can have imagined. Only a week has passed and his most expensive toy is already broken…

Nice work if you can get it..

Posted in Books, Talks and Reviews with tags , , , on September 19, 2008 by telescoper

I’ve just discovered that my review of Steven Weinberg’s new book “Cosmology” has been published today in the American journal Science. ( I think the link will only work if you or your institution has a subscription to the magazine.) It’s quite a nice job getting to review books like this, not because you get paid a lot (in fact, usually you don’t get paid at all), but because you get a free copy of the book and there is a clear incentive to read it. Reviews themselves are quite easy to do, as they’re usually only around a thousand words so don’t take more than an hour or so to rattle off.

The case of this particular book is quite unusual, thought, because Science usually only includes reviews of popular-level books, and this one is very technical. However, because Weinberg is such an eminent and well known physicist and this work is a long-awaited update of his classic Gravitation and Cosmology (published in 1972), it makes an interest subject for a review even if it is probably impossible for a non-specialist to actually read and understand all of it. It’s definitely not for the mathematically faint-hearted. In the review I stayed off the mathematical details and tried to explain how this book exemplifies the changes that have taken place in cosmology over the past thirty or forty years. Anyway, as you will see if you read the review, I liked the updated book a lot but I think it’s definitely for connoisseurs rather than absolute beginners.

Among the Literati

Posted in Books, Talks and Reviews with tags , , on September 16, 2008 by telescoper
Front Cover

Front Cover

I couldn’t resist including the following which is taken from the Times Literary Supplement (March 28, 2008, No. 5478). I get the TLS mainly for the crossword, and was chuffed when they actually published a review of my book From Cosmos to Chaos, published by Oxford University Press in 2006, and which was also reviewed in Nature and Physics World.

Between you and me the book developed out of a number of bits and pieces about probability theory I had written over quite a long time but never published. I cobbled them together in a rush and the book is a bit of a mess, really. Had I had more time it might have been more coherent. Perhaps. And it didn’t help that OUP didn’t allow me to correct the proofs, so there are lots of typographical errors. Anyway, reviewers have been very generous, particular Jim Bennett (Director of the Museum of the History of Science at Oxford) who wrote the review from which I have taken the following excerpt. And in case you think I edited out the bad bits, that’s not true. He actually reviewed four books in one article and I’ve just taken the bit about mine.

We can turn from inclusiveness and caution to the refreshingly opinionated writing of Peter Coles in From Cosmos to Chaos. This is really a book about probability theory and its application to different branches of science, but Coles is a Professor of Astrophysics, and cosmology is one of the most evident strengths of his book. Here again we learn much besides about our author: he supports Newcastle United, follows cricket and is keen on gambling. His is the only book of these four that has any formal mathematics to speak of, and we are encouraged not to give up at the first hurdle. He also uses illustrations from card games and seems oblivious to the fact that his fascination with contract bridge is just as likely as his affection for mathematical formulae to put readers off.

Coles’s preferred methodology in probability theory is Bayesian, based on an assignment of probabilities, understood as degrees of reasonable belief, to possible outcomes, rather than deriving them from frequency-based statistics.

This preference is carried throughout From Cosmos to Chaos and its epistemological implications are readily embraced. The “standard model” in particle physics, for example, is not absolutely right, but is currently the best bet among the alternatives. The Big Bang is not certain but the best available model given the present array of observational data. A “Theory of Everything” will not, pace Stephen Hawking, reveal the Mind of God – that is “silly” – it will be the most economical description of the universe and a good way of saving paper. The concept of entropy has a “subjective” aspect, not in the sense that anyone can use it as they choose, but because it arises from “the way we manage our knowledge about nature rather than (being) about nature itself’. Here there is a genuine engagement between the scientist, the historian and the philosopher of science.

Is it his approach based on the assignment of reasonable belief that has liberated Coles to express such clear preferences and opinions on all manner of theories? He is good on the difficulties and inadequacies in quantum mechanics, and charming in telling us that, having been warned beforehand that the subject would be confusing, he studied it for three years before realizing “what was the correct way to be confused about it”. He is amazed that the Copenhagen interpretation (where an act of measurement compels a realization of one or other physical states that existed previously only within a distribution of probabilities) could have been embraced seriously by so many highly intelligent people; but he has even less time for the multiverse, and contends that “in the gap left by the failure to find a sensible way to understand quantum reality there has grown a pathological industry of pseudo scientific gobbledegook”.

Coles suggests that the probabilistic descriptions given by quantum mechanics may simply arise from its incompleteness and he sees potential in a Bayesian approach, where quantum states are understood as states of knowledge rather than states of reality. He is pessimistic about the value of string theory: its apparent unconcern for predictable outcomes sets it outside scientific practice, while its plethora of possible accounts of our universe, known as the “string landscape”, would be better called the “string scrap-yard”.

Coles’s mathematics is not always easy to follow, but it seems to occupy its proper place, with the voice of the physicist helping us to position and appreciate it even without full understanding. In the chapter on the Big Bang, for example, the general reader may not understand all of the technical accounts, but she will get a real sense of what cosmology is and the kinds of claims it makes. These are not dogmatic but offered with a kind of realistic integrity and concluded by a series of “open questions” – fundamental but not yet answered. In the last chapter, probabilistic reasoning is applied to questions closer to everyday life, such as medical statistics and expert witnessing, and in a final – seemingly incongruous but enjoyable – addendum Coles addresses the breakdown of trust between scientists and the public. This does not arise from his subject and seems to be there just because the author – characteristically, one feels – had things he wanted to say. While bemoaning decline in the distribution of science understanding, he also berates the baleful effect of the scientific zealot, insisting that the scientific approach is pragmatic rather than idealistic. Coles urges scientists to engage honestly with the public and educationalists not to dumb down the school curriculum.

Science and Religion

Posted in Books, Talks and Reviews with tags , , on September 16, 2008 by telescoper

This is a write-up of a talk I gave at the University of Derby earlier this year. Although I’m not religious myself, I don’t agree with the likes of Richard Dawkins and am quite happy to engage in dialogue on such things, as I think science and religion ask different questions and get different answers. But there can be no dialogue if there is dogma, whether it be of theist or atheist flavour.

Does the Big Bang Theory Explode Religion?

The Big Bang theory has been around for many years, and provides an amazingly accurate description of how elements were formed in the early Universe, so does this mean we have removed the need for a creator God?

When eminent cosmologist Professor Peter Coles talked to a group of people of many faiths (and of no faith) at the Multi-Faith Centre in the University of Derby on 14 February 2008, he gave a very clear andsuccinct description of the theory, using wit and wisdom to engage the audience in an evening of information and discussion.

Peter appears regularly in the media. His expertise includes the Big Bang theory, the expansion of the universe and whether it will continue to expand or ultimately collapse. He is based in theSchool of Physics and Astronomy, Cardiff University. He entertained the audience with his wit and humour. He gave a brief history of cosmology, explaining the evidence for our current understanding of the Universe and worked his way back to discuss its creation.

The conclusion of the event was that cosmology tries to explain HOW the Universe came about but cannot tell us WHY. “If I was creating the Universe I wouldn’t have done it this way,” Peter joked. “I would have had something simpler, not all messed up like this. But it wasn’t my decision.”

For a fuller report on the event see

http://www.emsec.org.uk/index.php/Creation_of_the_Universe