Dark matter, dark energy, epicycles

Dark matter, dark energy, epicycles

Two years of blog posts and not a single one about astrophysics! But today, once again, I was interviewed by a journalist who wanted to know about dark matter. Wouldn’t we all! Around a year ago the maps of dark matter made by my collaborators in the
COSMOS project made the front page of Nature and as I was a co-author on the paper I got quite a few questions from curious journalists. I have a particularly fond memory of the intensive questioning I was given by Raphael Hittier of E-tele on the roof of the IAP building in the middle of a particularly cold Paris winter with a Siberian wind blasting across the terrace whilst Raphael asked me: “Qu’est-ce-que la matiere noir”? Ahhh…brr….

What indeed? I remember being astonished whilst I was a postdoctoral student in Durham to find out about the current orthodoxy, the Cold Dark Matter model (CDM for the initiated). And to learn that people had spent millions of hours of computer time on the world’s fastest computers making model universes filled with a mysterious substance whose exact properties were known very well (it’s a cold, dark, collisionless fluid which doesn’t interact with ordinary matter) — but whose precise nature was and still is a complete mystery. Okay, so we know what this stuff does — but what is it, anyway?

People have speculated that dark matter exists since at least the 1930’s when Fritz Zwicky realised that the rotation curves of galaxies could only be explained if there was a lot of matter in those galaxies which was not luminous. And in recent years gravitational lensing has given us spooky cosmic x-ray vision showing us where exactly the mass is, thanks to the deflection of light near gravitational sources. So maybe this stuff is really there.

As a graduate student, under the shadow of the cathedral in Durham, the mystery deepened even further. A lunch-time talk, I think it was, that wonderful Anglo-Saxon tradition (no-one would ever countenance such a thing in Italy or France, can you imagine working whilst eating?), rustling brown paper bags, crisp packets, coca-cola, and a presentation with a graph showing distance to supernovae plotted against the speed they were moving away from us. The “Hubble diagram”, named after mr. Edwin Hubble, who presented some of the first observational evidence that the Universe was expanding (which some of the theorists of the time actually expected). Every Hubble diagram I’d seen until then had showed a neat, linear relation between distance and velocity; the universe, the fabric of space and time itself, was expanding, and as a consequence more distant objects were moving away more rapidly. Except that in this Hubble diagram, there was something not right: some of the most very distant supernovae were just off the simple linear relation. Their error bars grazed the arrow-straight line of constant slope. But only a few of them.

It was an error, right? There was some mistake with the observations? Nobody wanted to believe that those outliers were real. It would meant that not only the Universe was expanding but also- gasp – accelerating. The cosy preferred model of the Universe that theorists had built up (which admittedly was looking a bit frayed for other reasons) would have to be discarded, radically revised, and someone would have to explain what exactly was pushing distant objects faster and faster apart, almost like a negative gravity.

But the outliers were real, and the Universe really is accelerating. The universe it seems is filled with some kind of invisible, dark energy, the exact nature of which is still unknown. It is this, somehow, which is accelerating the expansion of the Universe. Most of the mega-projects planned for astronomy in the next ten or twenty years will be devoted to finding out more about dark matter and dark energy, projects like LSST or Pann-starrs, which will map thousands of square degrees of sky to incredibly faint limits, making the most detailed maps of the universe, and hopefully ruling out some of the wackier models of dark energy.

But you do wonder, don’t you? I think of Mr. Ptolemy and his planetary epicycles, a complicated model which was replaced by something simpler and more universal (newtonian gravitation). The current cosmological model works really well — add in dark matter, dark energy turn the handle, and you can reproduce incredibly well all of the current cosmological observations to exquisite precision (modeling the formation of galaxies is another story). But the fact that almost all of the Universe (70% dark energy, 25% dark matter) consists of material of which we know almost nothing is more than a little unsettling — there may well be a hidden truth lurking in there, waiting to be discovered. A sign change that changes everything? An extra ingredient added to the model that makes 70% of the Universe suddenly become something else? We will find out soon enough, I hope.

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E. M. Gombrich and the history of art

E. M. Gombrich and the history of art

I have some amount of catching up to do. I realise that more than two months have elapsed between the last post and the one before that. It’s not as if I haven’t read anything or been anywhere: I just lacked a little bit of motivation, milord. So here goes again, this with E. M. Gombrich’s “History of art”:

It must have taken almost a year for me to read this book, but then I started it at the same time as Pynchon’s 1000-page “Against the day” and both of them are weighty tomes. The Gombrich was actually written in English, but I read the French translation, all five hundred pages of it. Another no mean feat in itself.

Gombrich’s book comes in many editions. There is the heavy coffee-table version, with colour reproductions of famous artworks interleaved with the text. I had bought the “edition de poche” which I carried with me during many months. In this edition, the plates are all at the back, and there are two bookmarks so one can find one’s way easily from the text to the illustrations. The green paper cover on my copy is now pretty worn, but all the pages are still there. The illustrations are a judicious selection of works of art spanning thousands of years of human civilization, from the caves in Lascaux to David Hockney. Deep underneath Paris, wedged between three other people in the tiny narrow seats of the line four metro, I felt more than a bit relieved to gaze at reproductions of Vermeer, Carvaggio, El Greco, Piero della Francesca, or to stare at pictures of famous buildings from Rome or Naples. I’m kind of disappointed to have finished the book, to no longer have those images with me wherever I go.

Gombrich is “old school”: he believes, unfashionably for today I suppose, that there is such a thing as art, that there are absolute standards of excellence which can be divined by any intelligent person and which endure over the centuries. Every plate is discussed and placed into context. I learned more than a little about each painter and architect but what was most interesting was the historical context. You see, at the start, thousands of years ago, there was not even the notion of “the artist”: there were artisans, who created objects on commission. Monuments for tombs, sculptures for public buildings. The renaissance in Italy, in Rome, in Florence: frescos for altars, paintings for churches. The best artists, like Caravaggio (I’ve just read a recent biography of him, maybe I will find time to write about it) could became very wealthy from their work. The next century, however, everything had changed. The commissions dried up; the reform in Northern Europe meant that displaying images in churches was proscribed. Artists could paint whatever they liked, but they lived a poverty-stricken existence; the best might be able to make a living from drawing portraits.

Fast-foward to the early 20th century. The impressionists: Paris is the world centre of art and culture. What I didn’t really appreciate was how much the impressionists were completely rejected by the critical press of the time before being accepted, famous and even rich. All this in the space of a few short years. It’s interesting to note that the term “impressionist” was derisory in intent — as was “gothic”, “baroque”, and “mannerist”. (As was Fred Hoyle’s “Big Bang”, too.)

In the last chapter, Gombrich makes some interesting comments about art and creation today. In our time, he says, it may be too early to distinguish between fashion and real movements in art which will still be talked about in a hundred years. But the initial rejection of the impressionists by the critics of their epoch has led to a gross overcorrection. Today, the most important aspect of any work of art is if it’s new; the search for novelty has become the most important aspect of creation. The public suffers from the same malady: the tradition of the new has rendered irrelevant all other traditions. This, added to the fact that artists today have an incredible freedom which has never existed in any time in history has led to some very strange effects indeed. Everyone is a revolutionary these days.

I’m not sure I completely agree with this. After all I spend more time at Beaubourg than I do at the Louvre; perhaps I am a sufferer as well. But it’s interesting to realise to what extent attitudes have changed over the centuries. I think after reading Gombrich’s book I do have a better appreciation of what constitutes a work of art, although it is not easy to put into words; the excellence with which the work has been executed perhaps, or the purity of the form, whatever that means. In the end it is perhaps better to look at the plates. Especially whilst making journeys through subterranean Paris, staring out the window from time to time at the utter blackness.

Imre Kertesz: Fatelessness, or "the happiness of the concentration camps"

Imre Kertesz: Fatelessness, or "the happiness of the concentration camps"

Last weekend I read Imre Kertesz’s slim novel, “Fatelessness”, a book about the experiences of a fourteen year old boy, George Koves, in the infernos of Auschwitz and Buchenwald. I had bought this book last summer in New York but had been inspired to read it by seeing a theatre production of Vassily Grossman’s “Life and Destiny” (maybe I will write about that tomorrow) and seeing a film about Primo Levi’s return to Turin.

“Fatelessness” is astonishing because of the completely dispassionate and unsentimental narration. One day in Budapest, on the way to work with his friends, fourteen-year-old George Koves is plucked from the his bus by a local constable and made to pass a long and tedious day in the customs house. No-one knows why they have been arrested, not even the constable (although those there carry the yellow Jewish star). Before long, he and his friends are made to march across town where they are locked up for the night; thrown into some strange and terrible play. The next day they are faced with the option of traveling to Germany now, to work — or later, when, they are told, the trains will be even fuller. George thinks as a boy might think about his knowledge of Germany and Germans, wonders idly that perhaps it would have been better if he had studied more foreign languages at school, reflects perhaps that he might now get a chance to see something more of the world. So he travels on the first train leaving. They are sixty to a carriage; but the next trains, they are told, will be even fuller. No-one shows any special maliciousness, with the exception of the German camp guards in Budapest; it seems, this is just something that happens.

The rest of the story everyone knows, in outline: the long journey without water, the arrival after several days of sweltering summer heat. Through a gap in the carriages’ wooden slats George sees the words “Auschwitz-Birkenau”, but of course they mean nothing to him. Arrival is chaotic, and he is relieved to see German guards: surely they will be able to restore some order. Lines form, people queue; in the factual, bare way it is described, they could be queuing at a post-office. There is an inspection by a doctor. George lies about his age; he says he is sixteen. The doctor takes a few seconds to decide who is fit and who is unhealthy. The fit ones live. George realises soon afterwards what has happened to the people who waited in the other line.

And so life begins in the camps. He is transferred to Buchenwald. Work wears him down almost to the point of death. He is treated with incredible cruelty, his body becomes the body of another person. He becomes weaker and weaker until he can no longer work. He is transferred to the hospital. He is really too young for such work. But he does not die, he survives until the liberation of the camps by the Americans in 1945.

All this you may have read before in many other stories from the camps, but what is different here is George’s ironic, detached voice. There is no trace of bitterness. This is the “banality of evil” that Hanna Arendt wrote about. He says: “We hung around and waited in actual fact, if I think about it, for nothing to happen. That boredom, together with that strange anticipation: I think that is the impression, approximately, yes that is in reality what may truly denote Auschwitz — purely in my eyes of course” (p.119).

Incredibly, George survives, and in the final chapter he returns to Budapest. People see his camp uniform. Tell us about the hell of the camps, a journalist asks him. But George refuses to be led, saying only that he knows what a concentration camp is, but not hell. But wasn’t it hell? He says, “Then I would imagine it as a place where it is impossible to become bored”. You must find some way of filling each second of each day of each month of each year; in the camps, all knowledge, all understanding of one’s situation arrives crashingly at once, and must fill out years of time. The journalist gives him his address on a scrap of paper; he throws it away.

In the next scene, he returns to his old family apartment building to find others living in his flat; his father was deported to the camps before him, his step-mother has remarried. But he does find some people in the building he remembers. They invite him in, but he rapidly becomes exasperated by their conversation. They continually talk about how things “came about” while they were stayed in Budapest during the war — the ghetto, shootings, and finally liberation. George instead recounts the story of the queue at Birkenau, the entry to the camps, and he says …”but it was not quite true that the thing ‘came about’; we had gone along with it too. Only now, and thus after the event, looking back, in hindsight, does the way it all ‘came about’ seem over, finished, unalterable, finite, so tremendously fast, and so terribly opaque. And if, in addition, one knows one’s fate in advance, of course.” (p. 257) George does not want to “forget” or “put behind” what happened to him because “…I now needed to start doing something with that fate, needed to connect it to somewhere or something; after all, I could no longer be satisfied with the notion that it had all been a mistaken, blind fortune, some kind of of blunder, let alone that it had not even happened.”

But fate is arbitrary; in the queue, his path could have so easily led to the left or the right. Moreover, awful crimes can be committed by ordinary people in banal circumstances (he talks about the beautifully tended flower-beds near the Auschwitz crematorium); all this has become possible thanks to our complete control of systems and processes; no one person is responsible; instead, each instead are part of a larger process, a larger mechanism. That, for me, was the core of this book.

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Irish Cinema: “Garage”

Irish Cinema: “Garage”

It’s not so often that I see an Irish movie in the cinemas here in Paris. Much longer than I remember. So it was with interest that I went to see “Garage”, a film by Lenny Abrahamson and starring the well-know Irish actor Pat Shortt, which opened here last week.

The plot is minimal: Shortt plays Josie, a simple-minded petrol station attendant deep in Ireland. It’s very much a film in that favourite genre of mine, the “Inaction movie”. His service station is a fossil, a museum of 1950’s Ireland. Shortt lives in a dingy room in back and spends his evenings either at the small pub in town (where a few of the clients are needlessly cruel to him) or staring out across the fields. The station’s owner, we are told, is content to let it decay because he knows that it will only be a matter of time before it will more interesting, financially, to bulldoze the site and build houses. This is, after all, the new Ireland. One morning the station’s owner arrives with his girlfriend’s son, who is to help Josie at the station.

Josie has been working at this garage for a very long time, and has dug a very deep hole of solitude for himself out in the fields where his garage is. He is desperate to make friends, to strike a bond with someone, but he just can’t communicate what he thinks, and no-one really takes the time to listen to him. He is relentlessly cheerful and friendly to everyone, regardless of what they tell him. Josie develops a bond of sorts with his new assistant, but all does not work out well.

I was reminded me of Patrick Kavanagh’s lonely farmer in that classic of Irish poetry,”The Great hunger”, condemned to spend the rest of his life staring at the field across the road. The countryside around Josie is beautiful and desolate in a very Irish way. You see, these fields and hills do not speak. There are no swathes of great open spaces inviting freedom and liberty here: this Irish landscape is very different from the one which Sean Penn’s wild-eyed seeker-after-truth experienced in “Into the wild” which is currently filling up the cinemas here in Paris. Instead, the flat level fields and shimmering lakes (all beautifully filmed) have a horizon which is foreshortened and proximate.

The film’s dominant register is a very subdued, tragicomic one, and the story proceeds relentlessly from one event to the next to the film’s inexorable conclusion. Everything is presented in an unaffected, ultra realist way. I thought a little of Aki Karismaki’s miserablist classic, “The matchstick girl” but the difference here is that Josie doesn’t fight back. I felt relieved to leave the cinema and find myself once again surrounded by the streets and buildings of Paris.