Budapest, winter (8-13 February 2017)

Budapest, winter (8-13 February 2017)

I made a short trip with ML to Budapest a few weeks ago. Budapest is one of those cities I visited when I first ‘discovered’ Europe in the early 90s before leaving for Canada for two years. Quite a few of those cities I have never returned to since then: Budapest, Prague, Vienna. You see, back then, I was attracted to this part of the world. For me Europe was above all Mitteleuropa, it was not the Mediterranean Europe of France, Spain and Italy. In fact, during those first few visits to Europe, I didn’t even visit Italy. Coming from the North, for me Italy seemed to be chaotic and noisy. Today, of course, I feel differently. But meanwhile, in my mind, Budapest rests frozen in the summer of 1991. What it would be like today?

After a short flight from Orly, we arrived at night:

it was bitterly cold, but I had my heavy coat for the mountains.

There is certainly a particular atmosphere in this city at night,

and at the same time there is no question that things have changed,

and the city is not as it was before. Although Budapest, as I learned, was always even in the depths of communism, a city known for its cosmopolitan lifestyle. But now some strange choices are being proposed:

Are you sure?

However, some things do not change, people still swim outside in at Széchenyi in winter when the temperature is barely above freezing:

You must swim fast

There are still a few mysterious things to see,

Many buildings have been restored, but not all of them,

there are still a few traces left from before the arrival of modern-day plate-glass windows,

Certainly food is important,

and during our stay we went to some wonderful bars and restaurants,

and outside in streets, you certainly need to wrap up warm:

And suddenly it was time to leave. Waiting at Budapest airport to board the plane in the depths of winter is a unique experience:

… and we were back in Paris once again. I enjoyed immensely our short visit, and hope to return soon…

Aki Kaurismaki’s “The other side of hope”

Aki Kaurismaki’s “The other side of hope”

I’ve long been a fan of the films of Aki Kaurismaki. I think, actually, I have seen every single film he has made (mostly at cinema festivals in Paris). So I was very happy to see that his new film, “The other side of hope” would be coming to the cinema screens in Paris this week. And this is less than six months since Jim Jarmusch’s “Paterson”, two directors who are always linked together in my mind.

I won’t say that “The other side of hope”, Kaurismaki’s new film, breaks stylistic grounds. It is merely the perfection of a cinematic style and atmosphere that Kaurismaki has spent his whole career refining. Every beam of pale, weak northern light falls through the windows at a slanting angle. Interiors are a muted pallet of blues and red, shot beautifully by Kaurimaki’s longtime cameraman, Timo Salminen. I admit I also felt relief, in the first few minutes of the film. Seeing the blue morning light on Helsinki docks together with that faint shimmer in the sky, I realised that Aki, unlike Jim, was is shooting on film. In fact, I find remarkable echoes between some photographs of Harry Gruyart and Kaurismaki’s films.

Welcome to Finland !

The plot is easy to summarise. Like his last film, “Le Havre”, Kaurismaki tells the story of an immigrant. In this case it is a Syrian, Khaled, who escapes Aleppo after almost his entire family are killed. He wants to start a new life. There are a few adventures, an arbitrary decision at the hands of the law, and after escaping “justice” he meets a traveling salesman turned restaurant owner, Wikstrom. Wilkstrom is also looking to start a new life. He is played by Sakari Kuosmanen, who’s been in Kaurismaki films since the 80s.

When people speak in Kaurismaki movies, there are no body movements. You would never expect someone to run into a room and shout “Freeze!”. You’ve perhaps heard the joke: how do you tell an extroverted Finnish person?” Answer – “He looks at your shoes”. There are long cold silences, and if one word will do, then one word is all it takes. In one scene, Khaled is is talking with a fellow refugee who advises him how to behave in Finland. “Don’t look too sad or they will send you back!” he says. But also, “Don’t smile too much, or they will think you are crazy!”

What would a Kaurismaki film be without a Volga station wagon?

Most people in the film behave with a simple common decency. We have become too accustomed to cinema where people display their emotions and the film is all the more resonant for it. Wilkstrom employs Khaled in his restaurant because it is the obvious thing to do, and no hands are wrung over the matter.

Kaurismaki has announced that this will be his last film, that he will not complete the “port city” trilogy that this film and “Le Havre” were part of. Ominously, Kati Outinen (who has been in many of Kaurismaki’s films) comes onscreen for a few minutes early on. She buys our traveling salesman’s stock of shirts at at a knockdown price, but refuses a job with him, announcing that instead she is moving to Mexico. I sincerely hope she can be persuaded to stay and Kaurismaki continues making films!

21st-century Insoluble Pancakes: dark matter, dark energy and how we know what we know

21st-century Insoluble Pancakes: dark matter, dark energy and how we know what we know

These days, we know far more about the origin, nature and fate of the Universe than at any time in history. Justification? Well, any good description of the Universe has to be able both to provide a framework for understanding what has happened in the past and provide predictions for what will happen in the future. It should, more than anything, be consistent with observations. During the past few centuries, the quantity and quality of observations we have made have vastly increased. Applying our new-found knowledge of physics we’ve constructed new instruments and these have allowed us to probe the contents of the Universe right back to the “last scattering surface”, the brick wall beyond which no photon can penetrate.

The Javalambre Survey Telescope

But there is a problem…

But there is a problem. Our current best cosmological model, the one which matches most observations, happens to contain two substances whose precise nature is still somewhat, shall we say, uncertain. This model is called “Lambda CDM” which means that it has Lambda, “dark energy”, and CDM, which stands for “cold dark matter”. Perhaps that should be with a comma, as in cold, dark, matter? In any case, these two substances, dark matter and dark energy, according to this “standard model”, account for most of the energy content of the Universe. Ordinary material is just the few percent left over. Needless to say, intellectually, this is not a satisfactory state of affairs.

Worse yet, this “standard model” has proved surprisingly robust. Data from the last big cosmology mission, Planck, analysed in part by my colleagues at the IAP, provided a final data set which seems to be in almost perfect agreement with the predictions of the standard model. There is just a hint of a discrepancy with a few measurements at lower redshifts from separate experiments which could be very well explained by imperfect astrophysical and not cosmological knowledge. At the same time, many teams have been trying for the best part of the last few decades directly detect dark matter particles. Other than the mysterious DAMA/LIBRA result, which shows an oscillating signal of who-knows-what there has been no hint of a dark matter particle. The range of particle masses excluded by other experiments are getting smaller and smaller. In particle accelerators like the Large Hadron Collider, no evidence has been found for kinds of particles that dark matter is supposed to be made of (although their mass limits have been narrowed).

From Bernabei et al., 2010. The wiggles could be … interactions with dark mater particles?

Certainly this situation has penetrated the popular consciousness. Many people aware that there is some “dark stuff” which nobody knows what it is. But you see, this is only half true. In fact, the characteristics of dark matter are known very well because it must have those properties for the fabulously successful standard model to match most of the observations.

Now, notice that I said most of the data. There are a selection of problematic data which may or may not be in agreement with our cosmological theory. Here’s the thing though. Any theory which purports to explain any discrepant observations has to only explain the discrepant observations, but everything else as well. That’s hard. Maybe there is no dark matter at all? Maybe it’s like Ptolemy’s “epicycles”, a complicated construct masking an underlying simpler truth? Or maybe gravity works differently on large scales?

XKCD and dark matter (R. Monroe).

The answer is…

So a few days ago on Facebook, buried amongst the cat videos, I came across this article by David Merritt which promised to be a philosophical attack on Lambda-CDM. I had high hopes, but reading the paper in more detail, it doesn’t seem to deliver a knockout blow to Lambda-CDM. Merritt characterises dark matter and dark energy as “conventionalist strategies”, a term borrowed from the great philosopher of science Karl Popper. This is bad: Popper explains that hypotheses which are added to a theory which do not increase its degree of falsifiability are conventionalist. I have to say, I adhere strongly to Popper’s ideas: if you cannot prove a theory wrong by observations, then it is not a real scientific theory. These “conventionalist strategies” are “sticking plasters” added to an existing theory when it should in fact be discarded.

Merritt also argues that a large number of the difficult and as yet unresolved problems in the standard model (many dynamical in nature) have been ignored by textbook writers. He provides an extensive hit-list of cosmology textbooks and whether or not his three named problems are discussed or not. They mostly are not. But is this a problem?

It seems to me that Lambda-CDM has been very successful given our ignorance of its constituents. The weight of observations consistent with theory is large. No other explanation has been proposed which agrees just as well with all this data, and I suspect many of the problems on Merritt’s list may simply be resolved by a better understanding of how normal matter interacts with dark matter. This is a very complicated process, and probably can only be solved numerically using very large computer simulations.

I am not saying that the current situation is satisfactory. I think simply that the hypothesis of dark matter and dark energy is more palatable, for instance, than arbitrary modifications of general relativity. Should we really discard Lambda-CDM for such a theory? Merritt argues that dark matter and dark energy are unverifiable hypotheses, but surely a modification to general relativity without any theoretical motivation is worse? That said, there are theories of modified gravity which have more robust origins. But as I said, we must not forget that that theories must also match all the existing observations, including the discrepant ones!

This century’s insoluble pancake…

If Flann O’ Brien was around today I am sure he would have had a lot of fun with these ideas. After all, O’Brien’s philosopher-scientist De Selby claimed that night was an accumulation of black air … but did he mean dark matter?

De Selby with some dark matter (John Farman)

O’Brien was writing at a time when the strange ideas of quantum mechanics were slowly becoming common currency. Schrodinger was lived in Dublin at the same time as O’Brien. O’Brien was keen to show how our modern conception of the Universe could sometimes lead to troubling conclusions. The “spooky action at a distance”, Einstein’s description of quantum mechanics, led to O’Brien’s rural police station with a direct link to eternity. And today, with dark matter and dark energy?

Observatoire de Haute-Provence: January 2017

Observatoire de Haute-Provence: January 2017

The Observatoire de Haute-Provence (OHP, as we call it to save words) is remote. To get there, you take the TGV to Aix-en-Provence, and then rent a car and drive north for around an hour. The nearest town is Manosque and the observatory is in the mountains. Each year I go there with two other astronomers to teach observational astronomy to a group of Masters-level students. The course is organised by Herve Dole who meticulously sorts everything out, helped out a lot of course by people at OHP and the Universities. We usually have two or three nights on the 120cm and 80cm telescopes, and usually it is clear for around two or two of those nights. There is a lot of work involved: for each group of students, there is a full scientific project, starting from planning the observations and finishing with a report and presentation. This year was particularly interesting: we successfully managed to observe an a transiting exoplanet, a planet which passes in front of its star and causes its light to dim.

The story of OHP is a long one. Observations started here at around the same time the IAP (Institut d’Astrophysique de Paris) was created a story which you can read about here. At the start, the OHP was, more or less, the “observing station” of the IAP, a place where the latest instruments could be tested out and where the still-new field of astrophysics could get the data it needed. I won’t go into the whole history of OHP here, but a succession of larger telescopes were built there, culminating with the mighty 193cm telescope in 1958. It was with this telescope that astronomers made the discovery of the first planet outside our solar system, 51 Peg, in 1995. The funny story here is that around the time I was studying for my Masters’ degree in Victoria, astronomers there were using an almost identical telescope at the Dominion Astrophysical Observatory for the same scientific project (with different instruments). Alas, their control of systematic errors was not quite good enough; they missed out.

Calling 1985

The situation at OHP has evolved. The number of astronomers using the site has greatly decreased in the last few decades with the arrival of other astronomical observatories situated in locations like Hawaii and Chile. Investments in the site have declined, reflecting a policy of concentrating resources in larger telescopes further away. But there is a lot to be said for smaller telescopes with modern instrumentation nearby, as I saw when I visited the JPASS observatory in Spain in 2015. There they have constructed a new small modern telescope on a site like OHP but with modern state-of-the-art detectors. Despite spending a lot of my time working on larger projects, I think there is a lot to be said for keeping sites like OHP open providing a compelling niche can be found.

Today, there are only a few people around after the sun sets. Although there are many telescopes, only one or two are regularly used. Some have been converted to remote, robotic operation. In the past, a chef cooked legendary evening meals each night, but today we re-heat meals made earlier in the day in the microwave (which never get things quite hot enough.) Still, the observatory has decided that educating students in the techniques of observational astronomy is a priority, and each year many nights of telescope time are dedicated to student projects. There is accommodation on-site which is very comfortable. The course that I teach in is part of the Master 2 program for astronomy in the Paris region, and we have tried very hard to keep an empirical, practical approach to our course. You wouldn’t expect it, but fewer and fewer astronomers actually travel to telescopes these days, and I personally appreciate seeing in person the telescope and dectectors even if they are not at the forefront of technology.

This year is my second trip to OHP with film cameras. I wanted to capture something of the feeling of being there in the middle of winter. Each morning one could see wonderful things like this:

Here are a a few photographs I took around the observatory during the day.

And as night falls, time to observe, or eat, depending if your observations are finished or not.

As each year, we stayed a week, arriving on Saturday afternoon and leaving early on the following Saturday. It was kind of nice to be slightly abstracted of the concerns of everyday life. When I wasn’t working, I worked on my article for Emulsive. I learned things. I learned that there is such a thing as the “Qatari Exoplanet survey” and our students successfully confirmed one of their transiting exoplanets (and I actually did a fair amount of work aligning their hundreds of images for them). We ate galette, which is a long tradition in France and in Provence it’s even better. And I took a lot of photographs of trees and domes. And group photographs. The best ones are always the unplanned ones. Like this one, taken at sunset. Almost everyone is there, except Herve, but here it is anyway:

At sunset. Michel, Karim plus students. Herve is missing.

I am already looking forward to returning in 2018!