Overview
- NASA administrator Jared Isaacman, testifying to a Senate panel on Tuesday, said he supports making Pluto a planet again and that NASA is drafting papers to revive the debate and honor discoverer Clyde Tombaugh.
- Any official change must come from the International Astronomical Union, which sets astronomical standards and has not agreed to reopen its 2006 decision.
- Pluto lost full planet status in 2006 under IAU rules that require a body to orbit the Sun, be round, and clear its orbital neighborhood, and Pluto fails the third test because it shares the Kuiper Belt with many icy objects.
- Supporters point to NASA’s New Horizons flyby in 2015, which found mountains of water ice, vast nitrogen glaciers, a layered atmosphere, and signs of internal activity, arguing for a definition based on a world’s geology rather than its orbit.
- Scientists remain split on how to define a planet, media coverage notes political interest in the issue including talk of executive action, and the next plausible venue for a formal review is the IAU General Assembly in 2027.