The U.S. National Aeronautics and Space Administration (NASA) has begun drafting a paper calling for the restoration of Pluto to ‘solar system planet status’. Pluto was the only solar system planet discovered by an American, but in 2006 it was demoted from planetary status by a decision of the global space science community. Calls within the United States to restore Pluto as a planet have been unrelenting, and NASA has now decided to address the matter at the institutional level. There is a growing possibility that U.S. influence could extend even to the scientific debate over “what should be considered a planet”.

Appearing before the Senate Appropriations Committee held in Washington, D.C., on the 28th (local time), Jared Isaacman, head of the U.S. National Aeronautics and Space Administration (NASA), said, “I am actively in agreement with the position that Pluto should be made a planet again”. He was responding to a question from Republican Senator Jerry Moran asking his view on Pluto being classified as a dwarf planet by the global scientific community.

A dwarf planet is a celestial body that, taking into account factors such as mass and shape, is categorized below a planet and above an asteroid. Along with Pluto, five bodies, including Ceres and Eris, carry the dwarf planet label.

Isaacman revealed in a further answer, “We are writing a paper that will propose the scientific community reexamine the discussion regarding Pluto”. The remarks suggest that the bid to restore the status of Pluto is being carried out systematically at the NASA level rather than as a mere personal wish.

Political and social factors lie behind why the restoration of Pluto to planetary status has emerged as an issue drawing attention from the U.S. Congress and NASA. This is because Pluto was the only solar system planet discovered by an American. In 1930, Clyde Tombo confirmed its existence at Lowell Observatory in Arizona.

Pluto lost its planetary status in 2006. It was a decision by the International Astronomical Union (IAU), the academic body that determines categories of celestial objects and assigns names.

At the time, the IAU judged that although Pluto orbits the Sun like other planets and is roughly spherical, it does not dominate its orbital zone gravitationally. Unlike Earth or Mars, Pluto shares its orbital path with debris-like small bodies, so it was deemed a dwarf planet rather than a planet.

For Pluto to be recognized again as a planet in the solar system, it is very likely that the IAU criteria for determining planets would need to be revised. The research paper that NASA plans to produce appears poised to serve as a logical basis for persuading the IAU and the global scientific community to change the planetary criteria.

However, the authority to decide which celestial bodies are considered planets rests entirely with the IAU. This means it will not be easy for the planetary status of Pluto to be restored simply because NASA wants it. That said, the increasingly unilateral posture of the United States in recent times could become a variable in the course of discussions related to Pluto. If the United States were to press hard for exceptions in the method of planetary classification specifically for Pluto, the global scientific community would likely face considerable confusion.