Is Pluto a planet?

Pluto is classified as a dwarf planet. This classification was established by the International Astronomical Union (IAU) in 2006 when they set new criteria for what constitutes a planet. Pluto did not meet these criteria because it shares its orbit with other objects in the Kuiper Belt and has not cleared its orbital neighborhood of debris. While some argue that Pluto should still be considered a planet due to its unique characteristics and historical status, it is officially recognized as a dwarf planet.

According to the International Astronomical Union (IAU), Pluto is classified as a dwarf planet. This reclassification occurred in 2006 when the IAU established new criteria for what constitutes a planet.

Pluto did not meet these new criteria, specifically failing the requirement to clear its neighboring region of other debris in its orbit. While Pluto does orbit the Sun and is large enough for its own gravity to make it round (assuming hydrostatic equilibrium), its orbit remains intercepted by celestial debris.

Historically, Pluto was considered the ninth planet in our solar system after its discovery in 1930. However, the decision to create a new classification system for dwarf planets was made partly because many other similar icy worlds and celestial bodies were discovered, and including them all as planets would significantly increase the number of recognized planets.

Despite the official classification, some still argue that Pluto should be considered a planet due to its unique characteristics and historical recognition.

No, according to the International Astronomical Union (IAU), Pluto is classified as a dwarf planet, not a planet.

Why it was reclassified

• In 2006, the IAU adopted a new definition of "planet." An object must orbit the Sun, be massive enough to assume a rounded shape (hydrostatic equilibrium), and have cleared the neighborhood around its orbit. Pluto meets the first two criteria but not the third, because it shares its region of the Kuiper Belt with many other objects (NASA, Saylor Bane paper).
• The IAU created the "dwarf planet" category for objects like this. Pluto was also given the minor-planet number 134340.
• Pluto is a Kuiper Belt object made mostly of ice and rock. It is the largest known trans-Neptunian object by volume, but Eris is more massive (Wikipedia).

The debate continues
Some scientists disagree with the IAU. In the article, one expert says, "Yes, Pluto is a planet," and argues that the other dwarf planets (Ceres, Eris, Makemake, Haumea) should count as planets too. He also points out that "Nature doesn't care what we call Pluto," meaning the question is partly one of semantics.

By the most restrictive definition, the Solar System has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune (Wikipedia: Planet).

No, according to the International Astronomical Union (IAU), Pluto is classified as a dwarf planet, not a planet. This reclassification happened in 2006 because Pluto does not clear its neighboring region of other debris in its orbit, as required by the IAU's criteria for planets. It is located in the Kuiper Belt and shares its orbit with other objects.

No — under the current official definition, Pluto is not a planet. It is classified as a dwarf planet.

The International Astronomical Union (IAU) reclassified Pluto in 2006 after establishing three criteria for planethood: a body must orbit the Sun, be massive enough for its own gravity to make it roughly round (hydrostatic equilibrium), and have cleared the neighborhood around its orbit of other debris. Pluto meets the first two but fails the third — it shares its orbital region with many other objects in the Kuiper Belt ( It was also given the minor-planet designation 134340 (

That said, the classification is debated. Some astronomers argue Pluto and other dwarf planets should count as planets, calling the "clearing the neighborhood" criterion arbitrary ( So the short answer is: officially a dwarf planet, not a planet — though the question remains contested.

No, Pluto is not currently classified as a planet. According to the International Astronomical Union (IAU), Pluto was reclassified as a dwarf planet in 2006 because it does not meet all the criteria required for planetary status, specifically failing to clear its orbit of other debris in the Kuiper Belt. This decision remains in effect as of November 2026. However, there is ongoing debate among some scientists and the public about whether Pluto should be reconsidered as a planet. For now, the official classification stands: Pluto is a dwarf planet, not a planet.

As of the latest IAU definition adopted in 2006, Pluto is classified as a dwarf planet rather than one of the eight classical planets of the Solar System. The International Astronomical Union set three criteria for a planet: (1) it must orbit the Sun, (2) it must be in hydrostatic equilibrium (nearly round), and (3) it must have cleared its orbit of other debris. Pluto satisfies the first two but does not meet the third, because its orbit intersects with many other Kuiper Belt objects. Consequently, it was reclassified as a dwarf planet (IAU, 2006) 【1†L4-L10】.