Mikko K.J. Kaasalainen (1965 – 12 April 2020) was a Finnish

applied mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History One ...

and

mathematical physicist Mathematical physics is the development of mathematical methods for application to problems in physics. The ''Journal of Mathematical Physics'' defines the field as "the application of mathematics to problems in physics and the development of ...

. He was professor of mathematics at the department of mathematics at

Tampere University of Technology Tampere University of Technology (TUT) () was Finland's second-largest university in engineering sciences. The university was located in Hervanta, a suburb of Tampere, Finland, Tampere. It was merged with the University of Tampere to create the ...

. Kaasalainen mostly worked on

inverse problem An inverse problem in science is the process of calculating from a set of observations the causal factors that produced them: for example, calculating an image in X-ray computed tomography, sound source reconstruction, source reconstruction in ac ...

s and their applications especially in astrophysics, as well as on

dynamical system In mathematics, a dynamical system is a system in which a Function (mathematics), function describes the time dependence of a Point (geometry), point in an ambient space, such as in a parametric curve. Examples include the mathematical models ...

Education and career

Kaasalainen received an MSc in theoretical physics at the

University of Helsinki The University of Helsinki (, ; UH) is a public university in Helsinki, Finland. The university was founded in Turku in 1640 as the Royal Academy of Åbo under the Swedish Empire, and moved to Helsinki in 1828 under the sponsorship of Alexander ...

in 1990, moving shortly afterwards to

Merton College, Oxford Merton College (in full: The House or College of Scholars of Merton in the University of Oxford) is a Colleges of the University of Oxford, constituent college of the University of Oxford in England. Its foundation can be traced back to the 126 ...

where he completed his DPhil in theoretical physics in 1994, supervised by

James Binney James Jeffrey Binney, Fellow of the Royal Society, FRS, FInstP (born 12 April 1950) is a British astrophysics, astrophysicist. He is a professor of physics at the University of Oxford and former head of the Sub-Department of Theoretical Physi ...

. After a series of post-doctoral and senior positions in Europe, he moved to the University of Helsinki and to his present institute in 2009. He led a research group in the Finnish Centre of Excellence in Inverse Problems Research. Kaasalainen was awarded the first Pertti Lindfors prize of the Finnish Inverse Problems Society in 2001. The asteroid 16007 Kaasalainen, discovered by ODAS in 1999, was named in his honour. The official was published by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Funct ...

on 7 January 2004 ().

Research

Kaasalainen's research interests mostly focused on mathematical modelling in various fields ranging from

remote sensing Remote sensing is the acquisition of information about an physical object, object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring inform ...

and space research to planetary and galactic dynamics. Typically, the models and mathematical methods Kaasalainen developed with his colleagues are connected with inverse problems. Two such topics featured prominently in Kaasalainen's research: * Asteroid lightcurve inversion, i.e., the reconstruction of the shapes and spin states of

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

s from their brightness measurements ( lightcurves), based on mathematical results and uniqueness and stability theorems that have been transformed into modelling algorithms with which a multitude of otherwise unresolvable asteroids can now be mapped. This method has also been used in the direct verification of the Yarkovsky–O'Keefe–Radzievskii–Paddack effect in the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

. * Analysis of large dynamical systems, where torus construction methodsM. Kaasalainen (1995): Construction of invariant tori in chaotic regions. Physical Review E 52, 1193. in phase space allow a compact representation or approximation of the dynamics of the observed system (such as a

galaxy A galaxy is a Physical system, system of stars, stellar remnants, interstellar medium, interstellar gas, cosmic dust, dust, and dark matter bound together by gravity. The word is derived from the Ancient Greek, Greek ' (), literally 'milky', ...

References

External links

Mikko Kaasalainen's homepage at the University of Helsinki

Finnish Centre of Excellence in Inverse Problems Research
{{DEFAULTSORT:Kaasalainen, Mikko K. J. 1965 births 2020 deaths Alumni of Merton College, Oxford 20th-century Finnish mathematicians 21st-century Finnish mathematicians