Harold F. Levison

Harold F. "Hal" Levison is a planetary scientist specializing in planetary dynamics. He argued for a distinction between what are now called dwarf planets and the other eight planets based on their inability to "clear the neighborhood around their orbits," although his proposal suggested the terms "unterplanet" and "überplanet" and used the word "dwarf" to mean something else.cite journal | last=Stern | first=S. Alan | coauthors=and Levison, Harold F. | year=2002 | title=Regarding the criteria for planethood and proposed planetary classification schemes | url=http://www.boulder.swri.edu/~hal/PDF/planet_def.pdf | format=PDF | journal=Highlights of Astronomy| volume=12 | pages=205–213, as presented at the XXIVth General Assembly of the IAU–2000 [Manchester, UK, 7–18 August 2000] ] Among other distinctions, he is the co-author of SWIFT, [http://www.boulder.swri.edu/~hal/swift.html] a commonly used symplectic integrator that solves planetary equations of motion for periods of billions of years. He currently works at the Southwest Research Institute and studies planetary orbits and their evolution through solar system history.

References