Florin Diacu
Encyclopedia
Florin Diacu born 1959, Sibiu, Romania, is a Canadian mathematician
and author.
in 1983. Between 1983 and 1988 he worked as a math teacher in Mediaş
. In 1989 he obtained his doctoral degree at the University of Heidelberg in Germany with a thesis in celestial mechanics
. After a visiting position at the University of Dortmund, he immigrated to Canada, where he became a post-doctoral fellow at Centre de Recherches Mathématiques
(CRM) in Montreal
. Since 1991, he has been a professor at the University of Victoria
in British Columbia
, where he was the director of the Pacific Institute for the Mathematical Sciences (PIMS) between 1999 and 2003. He also held short-term visiting positions at the Victoria University of Wellington
, New Zealand (1993), University of Bucharest
, Romania (1998), University of Pernambuco in Recife, Brazil (1999), and The Bernoulli Institute (at EPFL) in Lausanne, Switzerland (2004). He was invited to speak and lecture all over the world.
In the early 1990s he proposed the study of Manev's gravitational law, given by a small perturbation
of Newton's law, in the general context of (what he called) quasihomogeneous potentials. In several papers, written alone or in collaboration, he showed that Manev's law, which provides a classical explanation of the perihelion advance of Mercury, is a bordering case between two large classes of attraction laws. Several experts
followed this research direction, in which more than 100 papers have been published to this day.
Diacu's more recent research interest regards the n-body problem in spaces of constant curvature.
For the case n=2, this problem was independently proposed by Bolyai and Lobachevsky, the founders of hyperbolic geometry. But though many papers were written on this subject, the equations of motion
for any number, n, of bodies were obtained only in 2008.
These equations provided him with a new criterion for determining the geometrical nature
of the physical space. More specifically, he showed that celestial orbits depend on the curvature
of the space. For instance, the Lagrangian orbits (when three bodies are at the vertices of a
rotating equilateral triangle) can have bodies of any mass in the Euclidean (flat) space, but
the masses must be equal if the space has negative or positive curvature. Since Lagrangian
orbits of non-equal masses exist in our solar system (Sun, Jupiter, and the Trojan asteroids),
we can conclude that, if assumed to have constant curvature, the physical space is Euclidean
for distances comparable to those of our solar system.
Diacu also obtained some important results on Saari's conjecture, which states that every solution of the n-body problem with constant moment of inertia is a relative equilibrium.
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
and author.
Education and career
He graduated with a Diploma in Mathematics from the University of BucharestUniversity of Bucharest
The University of Bucharest , in Romania, is a university founded in 1864 by decree of Prince Alexander John Cuza to convert the former Saint Sava Academy into the current University of Bucharest.-Presentation:...
in 1983. Between 1983 and 1988 he worked as a math teacher in Mediaş
Medias
Mediaș is the second largest city in Sibiu County, Transylvania, Romania.-Geographic location:Mediaș is located in the middle basin of Târnava Mare River, at 39 km from Sighișoara and 41 km from Blaj. The health resort Bazna, officially recognized for the first time in 1302, is...
. In 1989 he obtained his doctoral degree at the University of Heidelberg in Germany with a thesis in celestial mechanics
Celestial mechanics
Celestial mechanics is the branch of astronomy that deals with the motions of celestial objects. The field applies principles of physics, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data. Orbital mechanics is a subfield which focuses on...
. After a visiting position at the University of Dortmund, he immigrated to Canada, where he became a post-doctoral fellow at Centre de Recherches Mathématiques
Centre de Recherches Mathématiques
The Centre de Recherches Mathématiques is the first mathematical research institute in Canada. It was founded in 1969, and was recognized as a national research center for the mathematical sciences in 1984....
(CRM) in Montreal
Montreal
Montreal is a city in Canada. It is the largest city in the province of Quebec, the second-largest city in Canada and the seventh largest in North America...
. Since 1991, he has been a professor at the University of Victoria
University of Victoria
The University of Victoria, often referred to as UVic, is the second oldest public research university in British Columbia, Canada. It is a research intensive university located in Saanich and Oak Bay, about northeast of downtown Victoria. The University's annual enrollment is about 20,000 students...
in British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, where he was the director of the Pacific Institute for the Mathematical Sciences (PIMS) between 1999 and 2003. He also held short-term visiting positions at the Victoria University of Wellington
Victoria University of Wellington
Victoria University of Wellington was established in 1897 by Act of Parliament, and was a former constituent college of the University of New Zealand. It is particularly well known for its programmes in law, the humanities, and some scientific disciplines, but offers a broad range of other courses...
, New Zealand (1993), University of Bucharest
University of Bucharest
The University of Bucharest , in Romania, is a university founded in 1864 by decree of Prince Alexander John Cuza to convert the former Saint Sava Academy into the current University of Bucharest.-Presentation:...
, Romania (1998), University of Pernambuco in Recife, Brazil (1999), and The Bernoulli Institute (at EPFL) in Lausanne, Switzerland (2004). He was invited to speak and lecture all over the world.
Research
Diacu's research is focused on qualitative aspects of the n-body problem of celestial mechanics.In the early 1990s he proposed the study of Manev's gravitational law, given by a small perturbation
of Newton's law, in the general context of (what he called) quasihomogeneous potentials. In several papers, written alone or in collaboration, he showed that Manev's law, which provides a classical explanation of the perihelion advance of Mercury, is a bordering case between two large classes of attraction laws. Several experts
followed this research direction, in which more than 100 papers have been published to this day.
Diacu's more recent research interest regards the n-body problem in spaces of constant curvature.
For the case n=2, this problem was independently proposed by Bolyai and Lobachevsky, the founders of hyperbolic geometry. But though many papers were written on this subject, the equations of motion
for any number, n, of bodies were obtained only in 2008.
These equations provided him with a new criterion for determining the geometrical nature
of the physical space. More specifically, he showed that celestial orbits depend on the curvature
of the space. For instance, the Lagrangian orbits (when three bodies are at the vertices of a
rotating equilateral triangle) can have bodies of any mass in the Euclidean (flat) space, but
the masses must be equal if the space has negative or positive curvature. Since Lagrangian
orbits of non-equal masses exist in our solar system (Sun, Jupiter, and the Trojan asteroids),
we can conclude that, if assumed to have constant curvature, the physical space is Euclidean
for distances comparable to those of our solar system.
Diacu also obtained some important results on Saari's conjecture, which states that every solution of the n-body problem with constant moment of inertia is a relative equilibrium.
Books
Apart from his mathematics research, Florin Diacu is also an author of several successful books. He wrote a monograph about celestial mechanics and a textbook of differential equations. Lately he became interested in conveying complex scientific and scholarly ideas to the general public. His most successful books in this sense are:- Celestial Encounters: The Origins of Chaos and Stability, co-authored with Philip HolmesPhilip HolmesPhilip J. Holmes is the Eugene Higgins Professor of Mechanical and Aerospace Engineering at Princeton University. As a member of the Mechanical and Aerospace Engineering department, he formerly served as the interim chair until May 2007....
, Princeton University PressPrinceton University Press-Further reading:* "". Artforum International, 2005.-External links:* * * * *...
(1996), (ISBN 0-691-00545-1). It won the Best Academic Book Award" of 1997. and was translated into Chinese, Greek, Hungarian, Japanese, Romanian, and Russian. This book is a history of ideas tracing the birth and development of chaos theoryChaos theoryChaos theory is a field of study in mathematics, with applications in several disciplines including physics, economics, biology, and philosophy. Chaos theory studies the behavior of dynamical systems that are highly sensitive to initial conditions, an effect which is popularly referred to as the...
. - The Lost Millennium: History's Timetables Under Siege, Knopf Canada (2005) (ISBN 0-676-97657-3), is a treatment of the problems of historical chronology. The author discusses how historical events were dated and presents the objections brought to the traditional approach by scientists like Isaac NewtonIsaac NewtonSir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...
and mathematicians such as Anatoly Fomenko. A modified Romanian version appeared in 2009. - Megadisasters: The Science of Predicting the Next Catastrophe, Princeton University Press (2009) (ISBN 0-691-13350-6) and Oxford University Press (2009) (ISBN 978-0-19-923778-4), traces the history of the scientific efforts made to predict and minimize the damage resulting from major catastrophes, such as tsunamis, earthquakes, volcanic eruptions, rapid climate change, hurricanes, collisions with asteroids or comets, stock-market crashes, and pandemics. This book also won "Best Academic Book Award" of 2011. From the citation: "[Florin] Diacu (Univ. of Victoria, Canada) is a mathematician who uses his professional and outstanding literary skills to provide a remarkable analysis of the 'science' of prediction. His chapter topics range from tsunamis, earthquakes, volcanic eruptions, and cosmic impacts to financial crashes and pandemics. Perhaps the most remarkable chapter deals with climate change. All these subjects are highly germane to the present world society awash with levels of communication hardly envisaged 10 or 20 years ago. Diacu's great depth of historical knowledge, penetrating insights, and familiarity with the associated literature has led to an erudite yet easily readable approach that retains critical scientific impact. In an age where the news media and large sections of society seem to feast on dire predictions and the threat of many 'imminent' disasters, Megadisasters should be required reading for all intelligent human beings. Summing Up: Highly recommended. All levels/libraries."