Should Pluto be a planet again?

This episode of Science Friday revisits the controversial 2006 decision by the International Astronomical Union (IAU) to reclassify Pluto as a 'dwarf planet,' a move that sparked public outcry and ongoing scientific debate. Host Ira Flato welcomes two leading planetary scientists—Dr. Amanda Bosch of the Lowell Observatory and Dr. Alan Stern, principal investigator of the New Horizons mission—to discuss the latest resurgence of the debate, spurred by NASA Administrator Jared Isaacman’s public campaign to reinstate Pluto as a planet via executive order. The guests argue that the IAU’s voting process was scientifically unsound and that planetary scientists have long rejected the official definition, favoring a simpler, more inclusive criterion: a celestial body that is massive enough to be rounded by its own gravity but not so massive as to trigger nuclear fusion. They emphasize that Pluto, with its complex geology, atmosphere, and moons, exhibits all the hallmarks of a planet and that the term 'dwarf planet' was never meant to diminish its planetary status but rather to describe size. The conversation also explores how exoplanet discoveries have revealed an astonishing diversity of planetary types, challenging our solar system-centric view and reinforcing the idea that classification should reflect scientific understanding, not arbitrary rules or public sentiment.