Take a look at the articles below, then write a discussion board post about your own thoughts about this. Is it a useful discussion to have among scientists? Among the public?

Assignment Question

One of the biggest “controversies” in recent astronomy history has been the “demotion” of Pluto from “planet” to “dwarf planet.” This has been a topic for a while, but got kicked up a notch in January 2005, when a team led by astronomer Mike Brown of California Institute of Technology discovered an object in the Kuiper Belt (a belt of objects beyond Neptune, of which Pluto is a part) that is larger than Pluto. This got a lot of attention from the public, in part because Pluto somehow intrigues people as the “little guy” in the solar system. To most scientists, this is mainly a matter of semantics. What we call the object doesn’t change what it is or where it is or the fact that it is an interesting thing to study (the New Horizons spacecraft recently gave us our first-ever close-up views of Pluto and its moons on July 14, 2015). Take a look at the articles below, then write a discussion board post about your own thoughts about this. Is it a useful discussion to have among scientists? Among the public? Does it help or hurt efforts to encourage interest in astronomy? https://neildegrassetyson.com/essays/1999-02-pluto… https://slate.com/technology/2006/08/breaking-news-pluto-not-a-planet.html

Assignment Answer


The vastness of our solar system, once comfortably encapsulated in nine planets, underwent a seismic transformation in 2006. The International Astronomical Union (IAU) orchestrated a redefinition of planetary criteria, and the consequences were profound, especially for Pluto. Once celebrated as the ninth planet, Pluto found itself relegated to the status of a “dwarf planet.” This paper aims to dissect the multifaceted controversy surrounding Pluto’s demotion, delving into the scientific intricacies, the cultural ramifications, and the public discourse that ensued, collectively shaping our understanding of the cosmos.

The IAU Resolutions: A Paradigm Shift

The IAU resolutions, particularly Resolution 5A, represented a paradigm shift in how we define and categorize celestial bodies (Plait, 2006). The traditional understanding of a planet, which once seemed straightforward, now hinged on stringent criteria, including the ability to clear its orbital neighborhood. This paper critically examines the scientific rationale underpinning these criteria and the implications for the classification of other celestial bodies. It questions the seemingly arbitrary nature of classifying objects solely based on their gravitational dominance and explores the dynamic evolution of our understanding of planetary characteristics.

Scientific Arguments: Pluto’s Unique Characteristics

Neil deGrasse Tyson’s 1999 article stands as a testament to Pluto’s uniqueness, highlighting its eccentric orbit, tilted rotation, and icy composition (Tyson, 1999). Tyson provocatively argues that these peculiar features align Pluto more closely with Kuiper Belt objects than with traditional planets, challenging its planetary credentials. The subsequent discovery of other trans-Neptunian objects further fueled debates on the validity of Pluto’s classification. This section undertakes a meticulous examination of the scientific arguments both for and against Pluto’s planetary status, providing an in-depth analysis of the ever-evolving understanding of celestial bodies in our solar system.

Cultural and Public Perception: Pluto’s Popularity

The demotion of Pluto, a distant celestial object, resonated deeply with the public, sparking widespread interest and discussions on what defines a planet (Plait, 2006). Beyond its scientific ramifications, Pluto’s cultural significance, its association with mythology, and its role in educational tools, such as the mnemonic device, offer profound insights into why its reclassification struck an emotional chord with the public. This paper undertakes a comprehensive assessment of the impact of the Pluto debate on science education and public engagement with astronomy, recognizing the pivotal role Pluto plays in capturing the public’s imagination.

The Tyson-Tombaugh Dilemma: Defending Pluto’s Honor

The clash between sentimentality and scientific rigor came to the forefront through the differing perspectives of Neil deGrasse Tyson and Pluto’s discoverer, Clyde Tombaugh (Tyson, 1999). This section navigates through their contrasting views, raising critical questions about the intersection of personal sentiments and objective scientific discourse. It explores the influence of emotional attachment to traditional classifications and the ongoing evolution of scientific knowledge. The discussion emphasizes the importance of maintaining objectivity in shaping our understanding of the cosmos.

Pluto in the Kuiper Belt: A New Celestial Identity

Revelations about Pluto’s association with the Kuiper Belt and its shared characteristics with other icy objects compel a reevaluation of its place in the solar system (Tyson, 1999). This paper investigates the implications of Pluto being designated as the “King of the Kuiper Belt” and its significance in unraveling the mysteries of the outer solar system. By exploring Pluto’s newfound identity, we gain valuable insights into the dynamic nature of celestial bodies and their interconnected roles within the broader cosmic landscape.

The Ongoing Debate: A Matter of Semantics?

The debate surrounding Pluto’s classification persists, with ongoing discoveries in the Kuiper Belt and beyond (Plait, 2006). This section delves into the semantic nature of the debate, questioning whether the terminology used affects the intrinsic nature of celestial objects. It reflects on the broader implications of such debates for the public’s perception of scientific knowledge, emphasizing the need for clear communication between the scientific community and the public to foster a deeper understanding of complex astronomical concepts.

Conclusion: Beyond Labels, Exploring the Cosmos

In conclusion, the Pluto controversy transcends the confines of astronomical classifications, serving as a microcosm of the evolving nature of scientific understanding (Tyson, 1999). This paper encourages a paradigm shift from an exclusive focus on labels to the exploration of the rich diversity within our celestial neighborhood. As humanity ventures further into the cosmos, the paper underscores the importance of fostering a harmonious relationship between scientific discourse, public engagement, and cultural perceptions, ultimately enriching our collective understanding of the cosmos.


Plait, P. (2006). Breaking News– Pluto not a planet! Slate.

Tyson, N. D. (1999). Pluto’s Honor. Natural History Magazine.

Frequently Asked Questions

1. Why was Pluto demoted from being a planet?

The demotion of Pluto resulted from the International Astronomical Union’s (IAU) redefinition of planetary criteria in 2006. Pluto’s failure to meet specific criteria, including the clearance of its orbital neighborhood, led to its reclassification as a “dwarf planet.”

2. What were the key scientific arguments for and against Pluto’s planetary status?

Scientific arguments for Pluto’s demotion emphasized its unique characteristics, such as an eccentric orbit, tilted rotation, and icy composition, aligning it more closely with Kuiper Belt objects. Arguments against the demotion often revolved around sentimentality, historical classifications, and the debate over what defines a celestial body as a planet.

3. How did the public perceive Pluto’s demotion?

The public perception of Pluto’s demotion was multifaceted. While some were intrigued by the scientific discourse and embraced the reclassification, others, particularly schoolchildren who grew up with Pluto as the ninth planet, found the change emotionally resonant. The debate spurred discussions on the definition of planets and astronomy in general.

4. What role did cultural factors play in the Pluto controversy?

Cultural factors played a significant role in the Pluto controversy, with its association with mythology, educational tools like mnemonics, and its role in popular culture. These factors contributed to the emotional attachment people felt toward Pluto, influencing how the public engaged with the debate.

5. How has the ongoing debate impacted science education?

The ongoing debate surrounding Pluto has had both positive and negative impacts on science education. On one hand, it has sparked increased interest and discussions about astronomy. On the other hand, it has highlighted the challenges of balancing scientific rigor with public sentiment and the need for effective science communication.