Solar System Inquiry Is Pluto a Planet

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Solar System InquiryIs Pluto a Planet?

• Tim Slater
• University of Arizona
• Department of Astronomy
• Conceptual Astronomy and Physics Education
  Research (CAPER) Team
• http//caperteam.as.arizona.edu

NASA JPL Navigator Center for Astronomy Education
http//astronomy101.nasa.jpl.gov
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Bellwork

• Who should get to officially decide if Pluto is a
  planet or not? Why?

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• Dear Tim I hope you are having a great time at
  the International Astronomical Union meeting in
  Prague and making lots of progress on the
  official naming of objects and setting the
  research agenda for the next ten years. Im
  sorry to interrupt, but weve just found
  something here you all might be very interested
  in. Our team has discovered faint object that is
  about 1,500 miles in diameter at a distance of
  about 5,000,000,000 miles from the Sun. We
  believe it is orbiting the Sun, although it is
  too early to know for sure. Also, it has a
  smaller body orbiting it, like a tiny moon.
  Weve started calling the object XENA and its
  tiny companion, GABRIEL. Do you think we might
  have discovered a new planet? Fingers Crossed,
  Michael Brown, Cal Tech

Generate a list of questions you need the answers
to before the committee can decide if Xena is a
planet?
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Generate a list of questions you need the answers
to before the committee can decide if Xena is a
planet?

• ????

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International Astronomical Union
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IAU DEFINITION OF A PLANET(current as of 26th
IAU General Assembly, August 25, 2006, Prague, CZ)

• object orbits a star
• object has enough mass to gravitationally pull
  itself into a sphere
• object has cleared debris from its orbit
  remaining from initial formation of solar system

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Questions to Ponder

• Is Pluto a planet by the IAU definition? Why or
  why not?
• Is Xena a planet by the IAU definition? Why or
  why not?
• Is Earth a planet by the IAU definition? Why or
  why not?

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Challenge

• As a small group, propose and submit written
  revisions to the IAU definition of a planet so
  that Pluto COULD be included, but that the total
  number of planets in the solar system does not
  exceed 10.

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Learning Plan

• Bellwork Who should get to officially decide if
  Pluto is a planet or not? Why?
• Exploration Class roll plays serving as the
  Naming Committee for the International
  Astronomical Union, the official body designated
  by the UN to name all objects and features beyond
  Earth by determining if new discovery of a
  planet-like object should be called a planet (see
  attached). Teacher collects student generated
  lists of questions the committee need answered to
  before the committee can decide if this new
  object is a planet?
• Concept Introduction Teacher provides a quick
  tour of the solar system and the official IAU
  definitions of the solar system and planet to
  students as well as what the IAU is and how
  astronomical objects are named by the IAU.
  Students are asked to determine if the official
  definition of a planet includes Pluto, and any of
  the new Kuiper-belt objects discovered. If time
  allows, students complete the scale model of the
  solar system inquiry lesson which could include
  a student-led solar system tour.
• Concept Application Students are challenged to
  propose and submit written revisions to the IAU
  definition of a planet so that Pluto COULD be
  included, but that the total number of planets in
  the solar system does not exceed 10.