Gravitational waves and rumors

An announcement from LIGO seems to be imminent…

Confirmation or invalidation of a discovery? We will see but it may be time to pause a little and reflect upon the rumors that have plagued the web since last Fall about a potential discovery.


Of course, we are all impatient to know more. Obviously also, some scientists imagine that there is fame to gain by announcing in advance a piece of news to which they have not contributed. Fame indeed: a sure way to become infamous…

Only the LIGO collaboration is entitled to announce anything, and at the time they choose proper. Because the time of physics, the time of carefully checking observations and measurements is not the same time as the one at which rumors spread over the web. And we should all be happy for it.

If some event is observed in a detector, one first has to make sure that this is a real cosmic signal and not an accidental injection of some unwanted signal. This may take months. In parallel, one has to analyse this signal in order to understand which cosmic event could have caused it: a supernova explosion, a merger of two neutron stars or two black holes. One has to make sure that this is not some background noise fluctuation that is unfortunately mimicking a real event. One has to identify as much as possible the parameters that can be measured (masses of neutron stars or black holes, distance of the event, etc.) and also the precision at which they are measured.

It is this long process that may eventually lead to what can be called a discovery (or to the realization that there is no significant result). And this process has to be presented in detail to the scientific community at large, which is the body that, in the end, will decide whether this is a discovery.

We can trust the LIGO collaboration to make an announcement only once they are through with this lengthy, but necessary process. This may now be very soon.

And to be frank, I am convinced that, if these rules were followed in some other sectors of our society, the world would be better off.

Pierre Binétruy

What are MOOC projects for?

Thank you all for the quality of your contributions to the discussion on MOOC funding. Tony asks a central question: what are MOOC projects for? Let me give my own point of view (and my motivation) on this.

It is true that, for the time being, Universities have mostly seen MOOCs as a way of raising their profile and ranking in an increasingly competitive environment. But I believe that we are undergoing a revolution in the way knowledge is disseminated (similar to the printing revolution initiated by Gutenberg) and this revolution means a new role for Universities, or maybe a new type of University.

In parallel, our world has become the global village foreseen by Marshall McLuhan. This struck me last November when the tragic events that took place in my own neighborhood in Paris were immediately known throughout the world and a wave of sympathy almost instantaneously lighted monuments all over the planet in blue, white and red.

In this context, Universities must make their own revolution. For centuries, they were reserved to the happy few, nationals (apart from a few world class universities) with a good curriculum, and in the age range between 18 and 25. Now they should address the whole world, with learners of all ages, diverse origins and cultures, diverse backgrounds and training.

There is clearly a market for that, and some private entities have started investing into this potentially fruitful market. Why should we bother? Because we are dealing with education and training, and thus with our own future as the human race. And because trusting this task only to cost-driven entities will necessarily lead to uniformity and formatting.

Now, you may rightfully think that Universities have also played their roles in formatting people in a certain way. This is why they need to do their own revolution. Why is this necessary? Because, in order to solve the huge problems of our global village, we need a diversity of talents , whether they are to be found in the suburbs of Rio, Capetown or Chongqing, the City of London, the villages of India or Silicon Valley.

But why should Universities get involved in this revolution? That, I understood from MOOC learners. Last spring, we released the French version of Gravity! At the end of the course, we received many thanks and congratulations from the learners. And one message was coming through: “nowadays, we are flooded with information, we have to digest it but no one asks us to think. This is what you did. It may be painful at times, but, in the end, it feels so good!” Now, isn’t that a splendid goal for the University of tomorrow to make people think? And who else could be trusted with such a mission?

Pierre Binétruy

The difficult issue of MOOC funding

I recently participated to a meeting organized by the French Embassy in London about the future of Massive Open Online Courses (MOOC), from a Franco-British perspective. Many actors in the field were present: platform leaders, university representatives and MOOC designers.


One of the major issues discussed in this meeting was funding. MOOCs are in principle free for learners. But they have a cost. To take the example of Gravity! we have estimated the overall cost, including the hours of all those who have worked on it, to around 100 000€. It may seem huge to you, but this appears to be in the ballpark of the cost of such online courses. And it does not even include the costs of the platform. Of course, most of these costs are covered by scientists providing their own free time to conceive and develop these courses, and to support the learners during the course. But one quarter of the sum concerns the technical aspects of video making and has to be financed with real money. In the case of Gravity! this was mostly supported by Sorbonne Paris Cité, a consortium of Paris Universities which initiated a plan for developing new MOOC projects. But how to sustain the effort in the long run?


Various possibilities were discussed in the London meeting. First of all, platforms are absolutely needed and require funding as well. They often started under the umbrella of a public entity, the Open University for Futurelearn in the UK, or the French Ministry for Higher Education for FUN in France. But they need to acquire some financial autonomy. There are various ways to cover costs, at least partially: some propose to buy the certificate of success (Futurelearn), others offer premium options at a cost (OpenClassrooms). And many look in the direction of corporate courses, funded by private companies for their own purposes, as a complementary source of funding.


But what about the funding of the courses themselves? Obviously universities have an interest in MOOCs: a successful one is great publicity. But their finances are tight and may not follow the development of this type of learning. Platforms return a small fraction of their revenues to the courses but this is far from covering the needs. Obviously, scientists are ready to devote some of their free time. But is it fair to ask young researchers to get involved, without any financial return, when they have to develop their own scientific career? In the case of Gravity! again, the team included around ten postdocs and Ph.D. students who were doing it for the fun of it. But what about course replays?


At Gravity! we have been following a slightly different path. We think that one of the strengths of MOOCs is their availability to everyone, irrespective of their origin, their country, their financial resources, or their level of education. We are thus trying to find donors to support the development of courses. This might not appear to be a priority compared to other good causes, like developing new medical treatments, fighting hunger or supporting children in need. But we believe that learning together about our Universe is the kind of universal activity that brings everyone together, and a way to respect each other, and realize that we are on a small planet that we need to preserve together.


LOGO_RFPU Vb2To be frank, we have not been very successful yet. We have created some years ago with George Smoot an Endowment Fund Physics of the Universe, but we have had difficulties convincing donors that the development of MOOCs is a valuable enough cause to make donations. We have also made a try at crowd-funding, with a platform created by one of our former postdocs. You may have seen in the first page of this website a proposal to fund an extra video for the Gravity! course, but it did not raise much interest: only 96$ since it has been out, and only 4 days still to go!


But we will pursue in this direction and not be discouraged. Certainly online courses will develop as alternatives to teaching as we envisage it now in our Universities. And students might have to pay for them. But we do believe that some other courses, like Gravity! should be aimed at everyone who wants to learn, and to think about the world around us, irrespective of their background, and financial means. So, if you know anybody susceptible to help us, then let them know about us (contact information may be obtained here).


Pierre Binétruy

The team behind Gravity!

At the time when the Gravity! course is reaching its conclusion, I think that it is important to stress that there is more to this course than the ubiquitous lead educator. This is also an opportunity to go backstage and show a MOOC (Massive Open On-line Course) in the making.

From the start, because we were addressing a very large audience of learners, we wanted to avoid using slides and voice-over. As strange as it may seem, it was important for me to keep an eye contact with the learners (even if, at the time, you were all as real as a quantum fluctuation). This meant using the techniques of movie-making, shooting the course in a studio (luckily, Paris Diderot has a beautiful one) and having a full technical team.

Let me now introduce the team. Here they are, on stage, in front of the “green screen” used to include background images or movies.

The Gravity! technical team

The Gravity! technical team

From left to right:

  • Jean-Luc Robert, the director and editor of all the videos,
  • Marie Verleure, our project manager for the full course,
  • Thierry Maillot, stage management, camera (and the beautiful special effects of the railer)
  • Lili Dongarra, director of photography,
  • Leo Friez, sound engineer,
  • Laure, intern, who developed a real skill at the clapperboard.

You have to realize that each video unit of 10 to 15 minutes was divided into sequences of some 8 to 10 sequences, each shot individually (sometimes three or four times when I was not good enough -and the team was merciless about that-, or when there was some light or sound problem, or a fit of the giggles). Shooting a single video was basically taking half a day, even more for the more complex ones (like the scenes with the candles which required the presence of fire security just in case we burn the whole place down!). As you may have noticed, we had difficulties with the light on the white board: too much light gave unwanted reflections, too little and one would not be able to see what was written. Here are a few pictures that give you an idea of the atmosphere on stage.

Inspired by Michelangelo

Inspired by Michelangelo





Lili’s attention, attracted by the black hole singularity

Something wrong?

Something wrong?



Not alone to cross the horizon

Not alone to cross the horizon

The session is reconstructed in the editing process, which takes hours in order to recapture the fluidity of the course, include pictures and movies. This was Jean-Luc responsibility. All the footage is then archived: we needed all the ressources of scientific documentation to do this. Just imagine: each 10 to 15 minute video session includes some ten sequences, each shot 2 or 3 times, with sound track and the images of 3 cameras (shooting on different angles). We were some of the heaviest users of data storage in the lab.

Then music was added. Let me say a few words about the presence of music and sound effects in the videos. I am a great believer that science and art have a common goal, which is to raise our understanding of the universe outside and inside us (the outer and inner space). Artists have their specific means and sometimes have their own short circuits to comprehend concepts or ideas that we physicists painfully identify after lengthy computations. So it was essential for me to involve artists in the conception of this course.

This is why I asked Gorka Alda, a contemporary music composer, to write an original score. A very unusual decision, as you may imagine. Another reason is that I find annoying the type of commercial music that tends to be associated with astrophysics. But why should there be music at all in a course like this? I know that has disturbed some, especially those with a good scientific background. Well, precisely for all the other learners: it provides a sort of familiar background which, after a while, helps to focus on the video content, and unconsciously relates some concepts with others (we specifically worked on that aspect with Gorka).

Once the videos are ready, one still has to build the whole course on the platform. This was the responsibility of Marie, our project manager. Long hours of days, nights and week-ends, to make sure that everything is in the right place, that the transcripts are correct, that all images are credited, that the correct versions of the videos are on-line, that the good answers in the quizzes are identified properly…

Until everything is ready on D day.

I should say that all this was performed by the whole team with dedication, passion, much interest for the science (the technical team was my first audience, and a demanding one) and good humour, as you may see from the pictures.

So let me conclude by warmly thanking -in George’s name and in my own, and I am sure on behalf of all the learners- the team who made Gravity! a reality.

Pierre Binétruy

Are they human?

But, are they human?

Welcome to all Gravity! learners

Welcome to all the learners of the on-line course Gravity on Futurelearn. This web site is meant to be your site.

You will find here all the news about gravity, as well as some of the activities that we will propose in the future. In this way, once you have completed the course, you can use your brand-new knowledge and expertise to know more about gravity, about the Universe and to accompany us in our exciting long-term scientific projects.

For the time being, you can go to the “Gravitational Universe” section where you will find detailed answers to some of the most frequently asked questions in the discussions of Gravity!


Pierre Binétruy, for the Gravity! educator team

Rumours about the detection of gravitational waves

These days, the web is full of rumours about a possible discovery of gravitational waves by the LIGO detectors (see for example here). LIGO is a set of several ground interferometers in the US. They recently started operations in their advanced version and have reached a sensitivity that makes a detection in the coming years probable. Has it already happened? Well, the rumour says that a detection occurred simultaneously in two detectors during an engineering run (used to test the apparatus).

This would be an exciting piece of news and a new window opened onto the Universe.

But before rejoicing, this rumour has to be confirmed. And to be frank, most rumours of this type never lead to a confirmation, because many other effects may lead to something that looks like a signal. Remember some years ago the neutrinos that travelled faster than the speed of light. Moreover, in the case of LIGO, there might be an even more devious reason: false signals injected into the detectors. Indeed, because gravitational waves are very difficult to isolate from the background, physicists have invented a “stress-guaranteed” method: a small group of physicists from the collaboration injects a false signal of gravitational waves into the detector without warning the rest of their colleagues, just to make sure that the false signal is identified and interpreted correctly. I was told (but did not check my information) that, on the last time this mischievous deed was performed, the rest of the collaboration had started writing the publication announcing the discovery before being told about the false input. So maybe once again, the LIGO physicists are playing with their own nerves (doing this in a engineering run, and not a scientific one, would be another degree in mischief).

In any case, if this rumour turns out to be real, it will probably take several months before the news is confirmed. There is no competition to the LIGO/Virgo detectors (which operate jointly, the Advanced Virgo detector in Europe being ready next year) and so one can imagine that the physicists will take their time to check and recheck the data before announcing such a ground-breaking discovery.


Pierre Binétruy