In 2006 the International Astronomical Union made a decision that broke hearts around the world — and was opposed by many planetary scientists who argued it was not only emotionally divisive, but bad science enacted through a flawed process that violated the IAU's own bylaws. Pluto — beloved, distant, discovered by an American — was stripped of its planet status and reclassified as a dwarf planet. Twenty years later the debate is far from over.

NASA Administrator Jared Isaacman just told the US Senate that he is firmly in the camp of making Pluto a planet again. NASA is working on papers to escalate the discussion through the scientific community and push for a formal revisitation of the 2006 decision.

And he has a point. 

Why was Pluto singled out?

The IAU's definition requires a planet to clear its orbit of debris. Pluto failed that test because it shares the Kuiper Belt with other objects. But here is the thing — Earth shares its orbit with asteroids. So does Jupiter. Furthermore, the further an object orbits from the Sun, the larger the area it must clear. If Earth were in Pluto's orbit, it would not clear that region of Kuiper Belt Objects either. This reveals a fundamental flaw in the IAU definition: it is inherently biased in favor of planets that orbit closer to their stars.

Pluto has towering mountains. Vast nitrogen-ice glaciers. A heart-shaped landform named after its discoverer Clyde Tombaugh. NASA's New Horizons spacecraft flew past it in 2015 and revealed a stunningly diverse world that looks a lot more like a planet than a lump of rock. And yet, in spite of these remarkable findings, the IAU has refused to reconsider the issue or reopen the debate — a telling sign that institutional stubbornness and emotion, not science, are driving the classification.

Tombaugh discovered Pluto in 1930. It was recognized as a planet for 76 years. It deserves to be recognized as one again.

Traditionally, decisions like this have fallen to the IAU — but that tradition deserves scrutiny. Science is not done by the decree of a self-appointed authority. The IAU's failure to act over nearly two decades, in the face of compelling scientific arguments and widespread opposition from planetary scientists, raises a legitimate question: what gives any single organization the sole right to decide what is and is not a planet? It may be time to consider other frameworks for how these definitions are made — ones that are more democratic, more scientifically rigorous, and more accountable to the broader scientific community.

We are calling on the IAU — and the wider scientific community — to reopen the debate on Pluto's classification and restore its planet status once and for all.

Sign this petition and tell the IAU: make Pluto a planet again.