www.pswscience.org Join PSW Science® as we welcome Alan Stern (PI New Horizons Mission) and Ron Ekers (Past President IAU). Alan and Ron will have a friendly discussion on the definition of a planet and Pluto's classification in our solar system. Please note lecture will be held on Monday, April 29th at 8 PM.
This lecture will describe scientific issues involved in deciding on a definition for the term “planet,” stressing the value of data developed since the 1990s that planetary types are more diverse than had been imagined. The lecture will describe a proposed new formal definition, the Geophysical Planet Definition (GPD), according to which “A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.” The lecture will explain why planetary scientists created the GPD, its advantages in classifying planetary bodies, and why it is superior to the definition adopted not long ago by the IAU that classifies some planetary bodies, such as Pluto, not as “Planets” but as Dwarf Planets. The lecture will also touch on flaws in the way the IAU’s planet definition was established and why voting is not an appropriate method for making scientific decisions, such as categorization.
Ron Ekers will explain how the IAU came to its definition of the class of dwarf planets which includes Pluto and why International Organizations have a key role to play when making decisions on scientific nomenclature. Agreeing on names and conventions is a necessary part of international science communications, although it is not itself a science. New discoveries made it clear that there is a new class of objects in the solar system known as the Trans Neptunium Objects (TNOs). It is now also clear that Pluto is very much smaller than originally thought and is similar to this new class of TNOs but quite different from the other “classical” planets. When International Scientific Unions makes decisions they include the views of representatives from all Nations and from all areas of science and that is why the IAU definition includes dynamical as well as Geophysical aspects.
For more information, please see the meeting website:
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