In the 1960s his research focused on
turbulence 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. Afterwards, Spiegel's work focused on models of the
solar cycle and radiative processes in hot stars. He authored or co-authored more than 100 papers involving collaborations with over 60 individuals; these papers have been cited well in excess of 3000 times. His 1966 article entitled "A thermally excited non-linear oscillator," co-authored with D.W. Moore, contains a discussion of chaotic dynamics in terms of the wandering of a trajectory from the vicinity of one
unstable periodic orbit to another. This 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 Arrhythmias" 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 insights and ideas have had a long-term effect 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 ideas since the 1980s. He also coined the field's use of the terms "
blazar" and "
photon bubble". ==Awards==