PBS Space Time Season 2019 Episode 30 Is Pluto a Planet?

PBS Space Time season 2019 episode 30, titled "Is Pluto a Planet?", delves into the controversial topic of whether or not Pluto should be considered a planet. Since its discovery in 1930, Pluto had been classified as the ninth planet in our solar system for 76 years until it was demoted by the International Astronomical Union (IAU) to a "dwarf planet" in 2006. This decision sparked a heated debate among scientists and the public that continues to this day.

The episode begins by explaining what a planet is and the criteria that are used to classify celestial bodies as planets. These criteria include the body orbiting around a star, being massive enough to have a spherical shape due to its own gravity, and having cleared its orbit of any debris or smaller objects. However, in 2006, the IAU introduced a new criterion that states that a planet must have "cleared the neighborhood around its orbit" of other debris. This was the reason why Pluto was reclassified as a dwarf planet, as it shares its orbit with other objects in the Kuiper Belt.

The episode presents arguments from both sides of the debate. Those who support the IAU's decision argue that Pluto is too small and too different from the other eight planets to warrant its classification as a planet. They also argue that the new criterion makes sense, as it reflects the current understanding of how planets form and evolve in our solar system. Those who oppose the decision argue that it was arbitrary and not based on scientific evidence. They also point out that Pluto has many unique characteristics that make it similar to the other planets, such as having a multi-layered atmosphere and moons.

The episode goes on to explore the history of Pluto's discovery and the reasons behind its classification as a planet. It also discusses the controversy that arose in the scientific community when new objects were discovered in the Kuiper Belt that were similar in size and composition to Pluto. This led to a debate on whether these objects should also be classified as planets. Ultimately, the IAU's decision to reclassify Pluto as a dwarf planet was seen as a compromise solution that acknowledged the new discoveries while maintaining consistency with the definition of a planet.

PBS Space Time's "Is Pluto a Planet?" provides a comprehensive and balanced view of the debate surrounding Pluto's classification as a planet. It presents the scientific evidence and arguments from both sides of the debate, allowing viewers to make up their own minds on the matter. The episode also raises important questions about the nature of scientific classification and our understanding of the universe. Overall, it is a thought-provoking and informative exploration of one of the most fascinating topics in astronomy.