NASA Chief Advocates for Pluto’s Planetary Status Revival in Senate Hearing

NASA Administrator Jared Isaacman has reignited a decades-old debate in astronomy by advocating for Pluto’s reclassification as a planet. Speaking at a Tuesday Senate hearing, Isaacman declared,

"I am very much in the camp of, ‘Make Pluto A Planet Again."

Isaacman hinted at ongoing research within the agency, stating that NASA is "doing some papers right now" to revisit the definition of a planet. He emphasized the goal of elevating this discussion within the scientific community to ensure proper recognition of Pluto’s historical status. Isaacman specifically referenced Clyde Tombaugh, the American astronomer who discovered Pluto in 1930 and initially classified it as a planet.

Why Pluto Lost Its Planetary Status

In 2006, the International Astronomical Union (IAU) established three criteria for a celestial body to be classified as a planet:

• It must orbit the Sun.
• It must be massive enough to achieve a spherical shape due to its own gravity.
• It must have "cleared the neighborhood" of its orbit, meaning it has no competing objects of similar size, except its own moons.

Pluto failed to meet the third criterion. As a result, it was reclassified as a dwarf planet, joining a category that now includes four other confirmed objects in the solar system. With a diameter of approximately 1,500 miles—roughly half the width of the United States—Pluto’s diminutive size further justified its reclassification.

Public and Scientific Reactions

The IAU’s decision sparked widespread public controversy. Many people viewed Pluto’s reclassification as an unjust demotion, lamenting the loss of a beloved planet from the solar system’s roster. Critics argued that the decision was imposed by an impersonal bureaucracy, disrupting a long-standing understanding of our cosmic neighborhood.

However, not all scientists support revisiting the debate. Mike Brown, a professor of planetary astronomy at the California Institute of Technology, criticized Isaacman’s stance, stating:

"While NASA administrators are free to wax nostalgic for the days when Pluto was a planet, the actual scientists working in the field will continue to try to explain and classify objects in the solar system in the way that actually helps us understand the world in which we live."

Bill McKinnon, Director of the McDonnell Center for the Space Sciences at Washington University in St. Louis, dismissed the debate as "a waste of time." He added,

"Of course Pluto’s a planet, but it