Alan Lightman - Scientific Work

Scientific Work

In his scientific work, Lightman has made fundamental contributions to the theory of astrophysical processes under extreme temperatures and densities. In particular, his research has focused on relativistic gravitation theory, the structure and behavior of accretion disks, stellar dynamics, radiative processes, and relativistic plasmas. Some of his significant achievements are his discovery, with Douglas Eardley, of a structural instability in orbitting disks of matter, called accretion disks, that form around massive condensed object such as black holes, with wide application in astronomy ; his proof, with David L. Lee, that all gravitation theories obeying the Weak Equivalence Principle (the experimentally verified fact that all objects fall with the same acceleration in a gravitational field) must be metric theories of gravity, that is, must describe gravity as a geometrical warping of time and space ; his discovery, independently with Roland Svensson of Sweden, of the negative heat behavior of optically thin, hot thermal plasmas dominated by electron-positron pairs, that is, the result that adding energy to thin hot gases causes their temperature to decrease rather than increase ; and his work on unusual radiation processes, such as unsaturated inverse Compton scattering, in thermal media, also with wide application in astrophysics . His research articles have appeared in the Physical Review, the Astrophysical Journal, Reviews of Modern Physics, Nature, and other journals. In 1990 he chaired the science panel of the National Academy of Sciences Astronomy and Astrophysics Survey Committee. He is a past chair of the High Energy Division of the American Astronomical Society.