Interview with Michel Mayor on 6 December 2019 during the Nobel Week in Stockholm, Sweden.

What did you want to be when you were younger?

Michel Mayor: When I was a child, I was in fact interested in science from the age of 10 years. Not specifically astronomy, but science. I was really a fan of quite different subjects: geophysics, plants and so on. When I was obliged to start a choice at university, it was for me very difficult to choose between mathematics and physics, so for the first year I chose both. After that I had to choose one and I chose to study theoretical physics. When I finished in 1966, it was quite easy to get a position as a PhD student because every laboratory was increasing, recruiting young people and so on. It was a little bit by chance that I choose astrophysics because on the same day, you have several opportunities, in statistics and mechanics, rather different domains. I said, “Okay, astrophysics, I will go and see if it is interesting”. I chose to continue and do my PhD in the domain of theoretical astrophysics. It was related to the problem of spiral waves and spiral galaxies. You are looking at a nice picture of a galaxy, you have sometimes two big arms. I did my PhD in this domain, absolutely nothing related to planets or velocities. This arrived only later.

Was there a particular moment that sparked your interest in science?

Michel Mayor: I’m not sure to have a specific moment where I started to say I will do my full life in the domain of science. I believe it was the responsibility of a very good teacher. At some moment between 12 and 16 I had a fantastic teacher in science who was doing experiments, extremely stimulating. It was not a moment, but the contact with this man having really stimulated the interest of myself but also all the younger colleagues. At some moment, he tried to show us some chemical reaction with chlorine. It’s a very dangerous gas and probably today it would be completely forbidden to do this kind of experiment. He said, “Oh, it’s a little bit dangerous, so I suggest you go outside in the back yard to do the experiment outside to not smell the chlorine”. He did a fascinating experiment, putting some copper inside this gas to show that it started to burn, and things like this. We also did quite a lot outside visits to the forest to see flowers and observe them. This was the important moment.

Maybe I can suggest another aspect of this relatively old professor. During his lifetime as an elementary school teacher, he continued to do his own research at home. He was studying nematodes, this nasty worm you can have inside your body. He was a renowned man in this field. For us, it was very impressive to this teacher having at home continuing research, receiving dirty water from any place in the world to identify new species of nematodes. Eventually I did not choose to study nematodes, but extrasolar planets.

What do you enjoy about science?

Michel Mayor: I believe science is one very fabulous way to satisfy your curiosity. I still have the same curiosity today when I’m reading some journal, equivalent to the Scientific American or general /- – -/. It’s so fascinating to see such the huge diversity of the work going on in the fundament of science, geophysics, archeology, medicine and so on. For me, it’s better than any fiction. I’m still continuing to have the same interest for the kind of research done by colleagues, and here it’s a good opportunity to meet people working in different domains. I love this.

What are the traits needed to be a scientist?

Michel Mayor: Curiosity is the most important point to be a scientist. If a student is good enough in all the basic tools of science, mathematics, physics and so on, and love to study natural problems, to see what kind of very unusual phenomena exist in the nature. “Why is this like this?” Sometimes you are looking at the sky and you have some clouds and you see some bright spots apart from the sun. “Why is it like this?” If he has this kind of mind, he could do science.

Do you enjoy teaching and mentoring?

Michel Mayor: I was appointed as a professor at the university during more than 20 years, so I believe I enjoyed it. I had to do some mandatory courses in astrophysics, but in addition to this, I had the choice to teach some different topics as the master degree, so you can choose. I would like to learn a little bit more in this domain, so you work to prepare the course and I liked to do that.

I’m very proud that I had I believe 18 PhD students in my life and I still have very good relationships with all of them. I was very proud that during many, many years, all of them got positions in science and continued to work in science. This was part of the pleasure of the Nobel Prize announcement. A few days ago, we had a special celebration at the observatory in Geneva. Some of my PhD students went from Chile, from South America, from Brazil, from the south of Italy to participate in this celebration. So, I believe, it’s good friends.

What do you look for in a PhD student?

Michel Mayor: I don’t know how we have to select people because it’s not always because they are absolutely extremely good at the university that they will be the best. I believe it’s how to select. Sometimes you believe that they will be extremely good and some are not so good, and sometimes you have someone who’s absolutely fantastic, asking good questions and so on. We don’t have a checklist to select people after, we have to try and see.

Can you tell us about your relationship with co-laureate Didier Queloz?

Michel Mayor: Didier was one of my undergraduate students first. After that he did his master thesis with me in the domain related to spectroscopy and things like this. Thereafter it was time for his PhD he chose to continue with me as a supervisor. It was just the beginning of a collaboration with some French colleagues to build a new instrument. It was a good opportunity so I asked him if he would like to collaborate with this development. It was the start of this long-term collaboration with him. He developed part of the software to analyze the signal we received. After the success at the end of a few years, before his PhD, there was the discovery of the first planet, and for him at least, it was a start in this domain, it’s evident. We have continued to work together for several years and still today we have some collaboration, part of the time in Cambridge, but also part of the time in Geneva we continued to collaborate.

How important is it to be open to new ideas and unexpected findings?

Michel Mayor: In principle, this is one of the most important points of science, to be prepared for the unexpected. If you are not, only working on what you almost know before, it is not a way to make progress. You must always be prepared for the unexpected. In the beginning the program was to search for a low mass companion to solar-type stars. It was mentioned brown dwarfs and extrasolar planets. Brown dwarfs are a very small stellar companions, having a mass too small to ignite and to start a nuclear reaction. But at the time, nobody knew what could be the period for this set of objects, so in some sense, it was a chance for us because we had adapted a rhythm of measurement to either kind of period. Then it was a chance because we discovered an object with the period of only four days. If we had started only from the theory, the period of a planet would be more like 10 years. We would have done quite sparse sampling of measurements. The fact that we had open eyes created a chance for us.

How do you deal with doubts in science?

Michel Mayor: Part of this doubt is a normal discussion in science. When you have new facts, I believe you have to be sure to analyze if it’s really strong. You have to remember that the first planet is a giant planet, like Jupiter, but with an orbital period of only 4.2 days. The theory at that time said that we cannot have a giant planet with a period shorter than ten years, because you need to agglomerate an ice particle and an ice particle does not exist close to a star. So it was a discovery by factor 1,000 with a theory. I believe it’s evident a normal discussion in science when you have a so big discrepancy with the theory, to be a little bit cautious.

This period for me was not so stressful, it’s not true. I believe it was superior to say, “What could be the other explanation? Is it a rotating star with magnetic activity? Is it a pulsation? For me it was only part of the normal discussion in science. You have something you need to understand, what could it be? Then after we had decided to postpone the announcement by one year, to wait to the next season, to repeat the measurement, to check if everything was still there – the same period, the same amplitude, the same phase and so on. It was only the first week of July, the only hypothesis to explain this is a companion, a low mass companion, plant three domain. So, we started to write the paper.

How did you discover you had been awarded the Nobel Prize?

Michel Mayor: I knew that many years ago I had been nominated for the Nobel Prize. But you know, I was not the only one. Several other people were also nominated, so I wasn’t surprised to not receive anything. I decided with my family that we didn’t mind all this, so we took vacation in October. We were taking professional commitment and things like this. This was the reason why we were in Spain and I was absolutely not looking or waiting for that. Then just before the announcement by professor Hansson we were leaving San Sebastián for the airport and I connected my computer. Suddenly I saw the beginning of the press conference at the academy and the first word was something like, “This this year, the prize will be given to three people having contributed to a better knowledge of the cosmos.” I said, “Oh, interesting domain”, and then after I heard the three names and then it was time to leave for the airport and then we tried to have a connection with the Nobel Foundation.

<Excerpt from phone call>
Adam Smith: “I’m calling from the Nobel Prize in Stockholm. May we speak for two minutes?”

Michel Mayor: It was too noisy at the bus station. It was impossible, so I said, “Please call us again”.

<Excerpt from phone call>
Michel Mayor: “Is it possible to do it in about one hour? I’m in the bus going to the airport. I will be at the airport in one hour and it will be quieter.”

Michel Mayor: This famous picture was taken by my wife when I was on my computer, just completely dominated by the flux of e-mails. At that moment, the conference had been done for a few minutes, so the rate of new e-mail congratulations, bing, bing, bing, every five seconds you have a new e-mail. Incredible! So that was the start of this long story.

How has your family supported you personally or professionally?

Michel Mayor: The life of an astronomer, going frequently to observe in many places in Europe and in addition to scientific conferences, it will be many months away from the family. Certainly when you have small children all of the burden of this situation was on the shoulders of my wife. From time to time we have been lucky enough to have the possibility to move all the family in south of France or later on in Chile. But nevertheless I had the huge support of my wife and three children working later on in science. Probably science was not too badly considered by my children, if they’ll have children, to continued, not in astrophysics, but in some domain of science.

What do you do in your free time?

Michel Mayor: My hobby, when I was young enough, I really loved climbing – high altitude sports, rock climbing, high altitude skiing and things like this. Evidently today, I like to continue hiking but no more climbing. But I still like to do downhill skiing, cross country skiing and things like that. I feel that when you are hiking, you have time to think on new ideas. I hope you spend some time just to admire the countryside, but also, I believe it’s the activity to walk. It’s very nice to have time to think, you have no e-mails, you have nothing. It’s good. I believe this is an important part of this kind of activity.

What fascinates you about the universe?

Michel Mayor: If you are in a dark place, on a /- – -/ or the top of a mountain and you’re looking at the sky, it’s difficult to escape good questions. Still today, I’m really fond of astrophysics.

Like many people in the past, you ask, “What is this?” This is a good aspect of astrophysics. You always have the possibility, if you are away from light of dawn, to ask this kind of question. For example, when you are in Chile, the center of the Milky Way at some moment, it is just at the zenith of where you are observing. You have the Milky Way here, it’s absolutely fantastic to see this, because it’s much brighter than in the northern sky.

How long do you think it will be before we detect life beyond Earth?

Michel Mayor: During the last 20-25 years, we have been lucky to explore all the diversity of the planetary system. Already today many colleagues are working on this specific new domain. Do we have such capabilities and possibilities to detect life? I’m quite sure that we know how to detect life. But we still do not have the good instrumentation to do it, but we have the path of how to do it. It’s a matter of years, money and maybe to have new, better ideas. I would say in one generation, it’s not for next year. It’s very difficult, but I’m quite confident. I don’t know the answer, but we will have the instrumentation to search and it’s good, it’s a good question. In science, it’s absolutely fantastic to still have extremely huge questions not solved. Cosmology, black holes, life in the universe, these are not details, so for young people, I believe it’s so nice to have huge questions still facing us.

Could we live on these other exoplanets that have been found?

Michel Mayor: The question of the possibility for humanity to move to an extrasolar planet is a very important question for me. I’d like to stop this kind of dream. If you consider that man went to the moon in three days, light needs one second. Let’s consider that a very optimistic possibility is to have maybe one good planet. Good in the sense that we can have good conditions at 30 light years. 30 light years is really our neighbour. Nevertheless, approximately one billion light years, one millionth second for the light to go. One billion times three days is completely crazy, that’s millions of years. So, there’s no way to go. Some people say we can accelerate the spacecraft, no, the energy to accelerate is impossible. Our planet is alive, there is not another one. We don’t have the possibility to immigrate. I’m not discussing the solar system, but extrasolar planets are not a possibility to immigrate for humanity. And Earth is so beautiful – why?

How special is Earth?

Michel Mayor: We are lacking the experience to compare another planet to ours. The only things we can say is that we have 200 billion stars in the Milky Way. If only one planetary system among 100 is convenient for a rocky planet it is still a big number. Let’s imagine how many planets in the universe are convenient for life. This is the next big question to search for. Not for very distant planets, but to analyse if life exists on much closer planets – and it is not going to these planets but just analyzing the luminosity and the spectra of these planets.

Watch the interview

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