Edward Spiegel
Encyclopedia
Edward A. Spiegel is the Rutherfurd
Professor of Astronomy
at Columbia University
and highly regarded for his work on convection
theory and on the application of fluid dynamics
to astrophysics
.
and on chaos theory
, returning to mathematical aspects of that subject from 1975 to 1985. In the late 1980s he concentrated on mathematical pattern theory in fluids and other systems. In recent years, Spiegel's work has focused on models of the solar cycle
and radiative processes in hot stars. He has authored or coauthored more than 100 papers involving collaborations with over 60 individuals; these papers have been cited well in excess of 3000 times.
"A thermally excited non-linear oscillator"
. by E.A. Spiegel and D.W. Moore contains a remarkable discussion of chaotic dynamics in terms of the wandering from one unstable periodic orbit to another. Their prescient vision anticipated much of our present day understanding of strange attractors. Like Edward Lorenz's famous paper, which appeared just a few years earlier, this paper provided one of the first models that showed how simple fluid systems can display complex dynamics.
"Cosmic Arrythmias" in "Chaos in Astrophysics" (Reidel 1985) is a compendium of Edward Spiegel's ideas for rationalizing cosmic phenomena. The article talks about the philosophy of why low-dimensional systems are relevant, useful and important in astrophysics. Between the lines, is the understanding that these ideas extend well beyond the subject of astrophysics
. The work also cites some specific cosmic examples where low-dimensional dynamics and chaos theory
may provide a key to understanding the astrophysical phenomena.
His original insights and ideas have had a long term impact on astrophysics
. For example, Spiegel's work on vortices in disks led to many papers in the 1990s, with vortices now recognized as key ingredients to the mechanisms by which disks maintain an accretion flux and how planets are able to form. His work on photo-hydrodynamics is now recognized as potentially important in pulsars, and the Moore-Spiegel oscillator and chaos have become influential from 1980s onward. He also coined the terms "blazar
" and "photon bubble
".
Lewis Morris Rutherfurd
Lewis Morris Rutherfurd was an American lawyer and astronomer, and a pioneering astrophotographer.- Life and work :...
Professor of Astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
at Columbia University
Columbia University
Columbia University in the City of New York is a private, Ivy League university in Manhattan, New York City. Columbia is the oldest institution of higher learning in the state of New York, the fifth oldest in the United States, and one of the country's nine Colonial Colleges founded before the...
and highly regarded for his work on convection
Convection
Convection is the movement of molecules within fluids and rheids. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids....
theory and on the application of fluid dynamics
Fluid dynamics
In physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
to astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
.
Career
In the 1960s his research focused on turbulenceTurbulence
In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time...
and on chaos theory
Chaos theory
Chaos 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...
, returning to mathematical aspects of that subject from 1975 to 1985. In the late 1980s he concentrated on mathematical pattern theory in fluids and other systems. In recent years, Spiegel's work has focused on models of the solar cycle
Solar cycle
The solar cycle, or the solar magnetic activity cycle, is a periodic change in the amount of irradiation from the Sun that is experienced on Earth. It has a period of about 11 years, and is one component of solar variation, the other being aperiodic fluctuations. Solar variation causes changes in...
and radiative processes in hot stars. He has authored or coauthored more than 100 papers involving collaborations with over 60 individuals; these papers have been cited well in excess of 3000 times.
"A thermally excited non-linear oscillator"
. by E.A. Spiegel and D.W. Moore contains a remarkable discussion of chaotic dynamics in terms of the wandering from one unstable periodic orbit to another. Their prescient vision anticipated much of our present day understanding of strange attractors. Like Edward Lorenz's famous paper, which appeared just a few years earlier, this paper provided one of the first models that showed how simple fluid systems can display complex dynamics.
"Cosmic Arrythmias" in "Chaos in Astrophysics" (Reidel 1985) is a compendium of Edward Spiegel's ideas for rationalizing cosmic phenomena. The article talks about the philosophy of why low-dimensional systems are relevant, useful and important in astrophysics. Between the lines, is the understanding that these ideas extend well beyond the subject of astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
. The work also cites some specific cosmic examples where low-dimensional dynamics and chaos theory
Chaos theory
Chaos 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...
may provide a key to understanding the astrophysical phenomena.
His original insights and ideas have had a long term impact on astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
. For example, Spiegel's work on vortices in disks led to many papers in the 1990s, with vortices now recognized as key ingredients to the mechanisms by which disks maintain an accretion flux and how planets are able to form. His work on photo-hydrodynamics is now recognized as potentially important in pulsars, and the Moore-Spiegel oscillator and chaos have become influential from 1980s onward. He also coined the terms "blazar
Blazar
A blazar is a very compact quasar associated with a presumed supermassive black hole at the center of an active, giant elliptical galaxy...
" and "photon bubble
Photon bubble
A photon bubble is a type of radiation-driven instability that can occur in the magnetized, radiation-supported gas surrounding neutron stars, black hole accretion disks or at the edge of ultra-compact HII regions around young, massive stars. The instability occurs as follows...
".