To accompany “Pluto is no longer a planet — or is it?”
- Research the definition of the word “planet.” Is Pluto a planet? Why or why not?
- Why might it be useful for scientists to have a specific set of criteria to determine what counts as a planet?
- When and why was Pluto reclassified from planet to dwarf planet?
- According to Jim Bell, what criteria should determine what counts as a planet?
- What are some features of Pluto’s geology?
- During Galileo’s time, what counted as a planet?
- When and how was Pluto discovered? Who made this discovery?
- What is the Kuiper Belt? Why did the discovery of the Kuiper Belt cast doubt on Pluto’s status as a planet?
- How did Mike Brown get his Twitter handle @plutokiller?
- What is Ceres? Why was it determined not to be a planet? Is that similar to or different from the reason Pluto was deemed to not be a planet?
- When and why did people stop considering moons to be planets? When and why were moons later called planets once more?
- What types of solar system bodies should be called planets, according to Philip Metzger? Why?
- What are the potential benefits of using a more inclusive definition for “planet” than the IAU’s definition?
- What are the potential benefits of using the IAU definition for the word “planet”?
- Think about the many ways the word “planet” has been used over the course of history. Which of its past uses surprised you? Explain why.
- If the definition of the word “planet” were up to you, how would you define it? What might be the benefits or drawbacks to your definition?