Paolo Farinella, planetary scientist

Migliarino (FE), 13 January 1953 - Bergamo, 25 March 2000

The reprints are piled untidily on the desk. I had gathered them for Paolo and was to have sent them to him as I had been doing periodically since he had fallen ill last July. There they were waiting for him to get over the heart transplant on the 8th of last February. The operation took place when he was in a critical condition; the long wait had greatly weakened his body. A heart attack on the eve of the operation had caused brain damage and had the operation been a success, the hope that Paolo would have recovered completely had been reduced to a faint glimmer. Yesterday, 25th March 2000, at 07:30, that glimmer went out.

My emotions well up constantly, one entwines with another and I find myself writing in an attempt to quell the melancholy. It is difficult to sketch a full picture of Paolo Farinella's life, especially for me having met him only a few years ago. Many others had the fortune of knowing him longer and could therefore give a fuller picture. Yesterday evening, when Giuseppe asked me to prepare a webpage dedicated to Paolo, I accepted willingly, although I realise that I can only trace a subjective and partial memory of him. However, I feel compelled to write something in order to keep his memory alive, to say something about this great man, who was physically so frail and minute.

Scientific Research

Paolo Farinella became a professor associated with the University of Trieste on the 1st November 1998, but his heart remained in Pisa, where much of his research had taken place and where he had many dear friends. Paolo was also a member of the Division of Planetary Science of the American Astronomical Society and of the International Astronomical Union. In addition he was part of the editorial committee of the international scientific magazines Icarus and Meteoritics and Planetary Science. In 1987, he was awarded the asteroid (3248) for his scientific research: the justification quotes Paolo's research on the dynamic and collisional evolution of asteroids and the Hirayama's families.

Paolo was also very active in the process of international disarmament: he was a member of the Scientific Council of USPID: the Unione Scienziati Per Il Disarmo, for the Committee of the Forum on the Problems of Peace and War and of the Pugwash Conferences on Science and World Affairs.

To discuss Paolo's research would require greater space and a more detailed research than a webpage can offer. His scientific production is extremely vast, to the point where we ask ourselves what the study of asteroids would have been without him. We can only hope that an anthology of his most important work will be put together in the near future.

Therefore, here follows just a brief and incomplete list of some of Paolo's works. Other information and an almost complete list of his studies (the last update was on 23rd June 1999) can be found in his CV which is still available on his personal website:


    For his articles, it is possible to find them using NASA Astrophysical Data Service from which one can also download many reprints.

  • List of papers on ADS

    Without a doubt, the area of research that was dearest to Paolo, and of which he may have been very proud (to the point that his collegues joked about it in a good natured way) was that on the Yarkovsky effect, carried out in collaboration with David Vokrouhlicky. The main result can be summarised by the fact that this effect acts on asteroids of up to 20km in diametre, causing the drift of the semimajor axis until they "fall" into the resounance which transport them towards Mars or into the space around the Earth (P. Farinella and D. Vokrouhlicky, Semimajor axis mobility of asteroidal fragments. Science 283, 1999, 1507). The study of the Yarkovsky effect represents maybe the peak of a lifetime of research on interplanetary dynamics and the collisionary evolution of asteroids. He investigated on objects in the main belt, those in the Edgeworth-Kuiper and also those in lagrangean points.

    Of the abovementioned studies, particular attention was dedicated to the transport of meteorites and also larger objects towards the Earth. In particular, Paolo always followed the expeditions to Tunguska from the first one in 1991. As Giuseppe Longo says, Tunguska was a myth of Paolo's youth and he was sorry that his health prevented him from taking part in the expeditions. Nevertheless, Paolo was an untiring right hand man in the organisation of the international conference Tunguska96 and had already started to work on the expedition Tunguska99. He was to have made a communication about it at ACM99, but his heart prevented him.

    In addition, Paolo studied the dynamic evolution of asteroids in relation to the danger of collision with the Earth. Just think about the many articles on Eros: by curious coincidence, the 14th of February, when Paolo was starting his last calvary, the NEAR probe entered into stable orbit around Eros. Paolo also studied the the flux of Tunguska-sized bodies of the main belt towards the Earth, estimating the impact frequency of one per century, and the interplanetary dinamics of the brightest bolides discovering a discrepancy in the evaluation of the physical characteristics of this population, whether based on their path in the atmosphere or on their orbital evolution.

    Paolo also dedicated himself to hypervelocity collisions, of both asteroids with asteroids and space debris against artificial satellites. In particular, he had recently demonstrated that with constellations of satellites the impact risk rose tangibly.

    Some Personal Memories...

    I met Paolo in April 1997 at the annual conferece of the Italian Astronomical Society, that was held in Bologna in the CNR Research Area. We had had the opportunity to send each other a few e-mails and so I took advantage of his coming to Bologna to meet him in person. After his speech, Paolo decided to go back to his lodgings at the University and I accompanied him. We went for a long walk, discussing planetology and in particular, I told him about my recent work. At that time, I was passing a difficult period in my work as a researcher, and Paolo understood immediately. He didn't think twice before inviting me to Pisa to hold a seminary on the impact of meteoroids with artificial satellites. This event took place about one month later.

    That seminar and the one which followed represent an important step for me: for the first time someone believed in my research, someone found it interesting enough to spend a few lira to get me to do a seminar. Paolo was the first person to believe in my research, to transmit his belief, to give me the strength to go on. I had already had to start from scratch twice due to bad choices and I can't be sure that without Paolo I would have found the strength to start again a third time. I will never be able to thank him enough for this.

    Shortly afterwards, Paolo involved me in a research project on the interplanetary dynamics of the brightest bolides, something similar to the article written in 1995 by Tadeusz Jopek, Christiane Froeshlè and Robert Gonczi (T.J. Jopek et al., Long-term dynamical evolution of the brightest bolides. Astronomy and Astrophysics 302, 1995, 290). In this new research, besides myself, we were joined by Patrick Michel. The project finished in June 1999, just a couple of weeks before Paolo was taken ill, and the results were published in January this year (L. Foschini et al., Long-term dynamics of bright bolides. Astronomy and Astrophysics 353, 2000, 797). In addition, thanks to Paolo, in March 1999, I started collaborating with Giuseppe Longo and the scientific expedition Tunguska 99.

    Last autumn, when I was looking for a job, Paolo helped me by suggesting that I applied for an ESA fellowship, which required a period at the Astronomic Observatory in Nice. He wrote me a reference letter although all he had at hand was paper and a pen. However, when he learnt that I had won a job at TeSRE, it was him who asked me to stay in Italy. I couldn't say no to Paolo, and not because he was ill.

    In those days of spring 1997, an intense correspondence via e-mail developed which went on until recently, alternated with letters when access to a computer was not possible. The last note I received from him was on the 3rd February, and was delivered by Mario Carpino. The last letter I sent to him was dated the 13th February 2000. Maybe he never got to read it.

    In our correspondence we discussed many things, not just science. Paolo often advised me to follow the "unwritten rules" of research, thus preventing me to make less mess ups than I usually did. Thinking of his advice, the beginning of the tenth Canto of Dante's Inferno come to mind:

    My master now made his way by a hidden track between the wall of the city and the torments, and I close behind him. "o thou of loftiest virtue," I began "who leadest me round as thou wilt through the sinful circles, speak to me and satisfy my desires"

    We exchanged opinions on literature, articles, war and disarmament. Every now and then we discovered that our views differed greatly, but Paolo was a person with whom it was possible to talk even if he had a different opinion. And although he was firmly convinced of his beliefs, he certainly never wanted to change others' way of thinking.

    We also discussed science, right up until his last days. In fact in one of his last letters, dated 13th August 1999, Paolo told me about his point of view on the matter:

    I am replying to you in too brief and schematic way about the question of how scientific work is carried out. First of all, I believe that there is a great variety of subjective approaches, a bit like in art. As far as I'm concerned, I rely a lot on reading, that is following the work of others, the latest news etc. (through conferences as well); every now and then I make "unforeseen" connections between problems and subjects usually considered separately, and then I start to explore the conseguences. Very often, I do not have the "technical" (physical, mathematical, numerical) competence to go ahead alone and so I try to involve a (usually younger) colleague to develop the work. At the end, I also like to follow the written and oral presentation, to make the article more legible and digestible for those who work with me. On other occasions, when working with my peers or older colleagues, I try to discuss open problems in a deeper way, the dark points, alternative models etc., and I try to identify the various steps of a road that could clarify things. I know that I should give further examples, but at the moment I even find writing tiring...
    One last thing, I agree with you on the "convivial" aspect of many scientific projects, but I don't think that its importance lies in what is said so much as in the human relationships and the friendships with people with differing backgrounds and experiences, but with common interests (and a good knowledge of english is very useful here!). I believe that this is one of the great priviledges of scientific work that enriches from many points of view. For me, the friendship and the (potential, at least) collaboration of dozens of colleagues around the world is an element of great joy and reassurance, although, but not only in particular circumstances like the present ones...

    Impact Workshop in Torino (1st-4th June 1999). Paolo Farinella is indicated with the arrow.
    Click on the image to enlarge it.

    Let's remember the Paolo that we knew, who we see in a photograph taken at the last congress he attended, in Torino (IMPACT, 1st-4th June 1999). Let's remember him like this, surrounded by his friends who have had the honour and the joy of knowing him. It is unbelievable that for such a great-hearted person his heart was to be his weak spot. Thank you, Paolo, for everything you've done.

    Luigi Foschini

    26 March 2000

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