Happy birthday, Jaan Einasto! Colleagues talk about Einasto on his 89th birthday

Kairi Janson | 23.02.2018

Today is the birthday of Jaan Einasto – an astronomer who discovered the large-scale structure of the Universe with his colleagues and was one of the first to encounter the question of the existance of dark matter. On his 89th birthday, colleagues from Tartu Observatory Peeter Tenjes, Laurits Leedjärv, Tõnu Viik, and Elmo Tempel talk about Einasto.

Jaan Einasto observatooriumis 89. sünnipäeva tähistamisel
Jaan Einasto at his 89th birthday celebration at Tartu Observatory

Peeter Tenjes, Senior Research Fellow at the Department of Physics of Galaxies and Cosmology

I remember the first time I met Jaan Einasto well. I was only a first year physics student at the time. Einasto was the head of the physics group that was looking for young students and I came to meet with the group. When I arrived they were having meeting and was therefore asked to sit in the front room and wait for it to end so that Jaan could talk to me.

I heard the meeting very well. Retrospectively, I know that it was just after Jaan Einasto, Enn Saar, and Ants Kaasik’s first paper about dark matter in galaxies and around them was accepted to Nature magazine. And on that meeting, Jaan was saying that the results were very important and fresh and that the group should direct most of their activity there if possible. They discussed how to divide the tasks. I remember only that Jaan asked how my math was – I had no problem with math – and gave me a book in English about galaxies to read.

If I had to point up one of Jaan Einasto’s qualities, I would say that he is, above all, a researcher-astronomer. It is in his nature: he has this so-called researcher’s curiosity in his blood. He is daringly interested in all that is new – for example, he realized that personal computers were to change the world in the very beginning.

For a researcher, it is important to realize when a research topic is a dead end. When it has turned out that researchers have been heading towards the wrong direction, Jaan has been very resolute and willing to let the topic go. I think that these qualities were the reason why one of the greatest figures of physics and cosmology Yakov Zel'dovich highly appreciated Jaan and was pleased to communicate with him.

Tõravere observatory is Jaan’s whole life. He cares for the observatory and passes this concern to others as well. His main concern is the sustainability of the observatory both in short and longer terms. The presence of young people at the observatory and their possibilities to do research in astrophysics is a quite considerable base for the sustainability. Through this, the observatory is connected to the University of Tartu as well because young researchers find their way to the observatory through their studies.

The other aspect is comprehending that astronomy is an international field and without strong international cooperation the freshness and alertness concerning research will fade. These are the two topics that he often talks about.

But, of course, research is not the only thing that Jaan finds interesting. He always has a lively interest towards the processes going on in the society. Jaan likes to talk about the role of research in society and the problems of financing research both here and elsewhere. His great hobby is classical music.

Laurits Leedjärv, Senior Research Fellow at the Department of Stellar Physics

In November 1978 when I was a first year physics student, Jaan’s daughter Maret who was a third year student at the time was organizing a visit to Tõravere for those who were interested. I remember that Jaan Einasto talked to us about astronomy next to the big, 1.5 metre telescope which was quite new back then, having been in use for about 3 or 4 years. I had heard Einasto’s name before, probably in connection with discovering dark matter, and felt somehow proud that such a great researcher had come to meet with first year students.

One cannot influence the talent and abilities they were born with but Jaan has been a great example of developing and implementing those qualities. Nowadays it is said that one has to change their field after every 5 to 10 years, seek new “challenges”, but Jaan has showed that it can be done the other way as well – if one is consistent in doing the same thing they can go very far. Jaan has been doing that for 75 years now. He has told himself how his father took him to the old observatory to see Taavet Rootsmäe in 1943. And Jaan has stayed in this skysphere – head in the open space of the Universe, feet surely on the ground – to this day.

There are many stories that come to mind when thinking of Einasto. Jaan has described many of them himself in his memoires. I think I have not had the luck to witness the most vivid ones. But once again I could flash back to being a student. When I was a bit older I would go to astronomy seminars held in Tõravere. And during a presentation, Jaan used his hands to show what the measurements of the part of the Universe that he was doing research on were like: ... let’s take this cylinder, 150 megaparsecs one way, 30 megaparsecs the other ... The cylinder which size would need 19 zeros to express in kilometres was the size of a wash bowl in his hands. This is how simple the Universe is!

Tõnu Viik, Scientific Advisor at the Department of Stellar Physics

Our first encounters were in the autumn of 1958 when I had come to the university and had to become a sputnik observer according to the rector’s directive. Jaan gave us lectures about the theory of the movement of the sputnik at the old observatory and the old anatomical theatre – he had become the head of the observation station. He started tilting me and other physicians towards astronomy and succeeded with many of us. Ever since then we have been colleagues. Jaan has often asked me for my (administrative) advice so I can think of myself as his secret adviser.

I think of Jaan as a person who can be respected. I especially respect him because before he finished his own PhD thesis, he also put his teacher Grigori Kusmin’s thesis together. Kusmin was known for not wanting to publish his own work because solving the problem was enough for him.

As a researcher, Jaan is hard-working, he has put together a great team and taken good care of them. Ant he was the first who, deep in the Soviet era, started publishing his work in English in good magazines.

I have many stories connected to Jaan: I remind you that I have known him for 60 years. I remember that when he was the head of the sputnik station, he bought himself a motorbike, and the story goes that he had said that it was a fast machine – two hours to Elva (distance about 30 km). But what the jokers left out were the last words of Einasto’s sentence – two hours to Elva and back.

Elmo Tempel, Senior Research Fellow at the Department of Physics of Galaxies and Cosmology

Although Jaan wasn’t my supervisor, I think of him as one of my mentors. In the beginning of my PhD studies I went to the astrophysics institute in Potsdam, Germany many times with Jaan and I appreciate the discussions that Jaan and I had in Potsdam.

I think that Jaan is the same as a person and as a researcher. He is greatly dedicated to his goal in his activities and if he decides to do something, he usually finishes it. As a researcher, Jaan is not a lone wolf. Most of his results have been made in cooperation with colleagues. Jaan appreciates his colleagues’ opinion and takes it into account. I think of Jaan as a person who I can always count on and whom I can always as for an advice if I need to.

Jaan has been able to merge his hobby with his job. He values what he does and this has made him a spectacular person. I think that Jaan is a great example that one should never set their goals too low.

Jaan is an inspiring person and I always get many new interesting ideas talking to him. Jaan knows how to inspire and motivate his colleagues and because he is passionate about research, he is always a radiant person when talking about it. This is what I admire about Jaan: he does research with passion and commitment and this radiates to others as well.


Nine years ago, Einasto's vivid memoirs and fascinating stories were captured at the old observatory. The video can be seen on UTTV.