Pluto and dwarf planets; astronomical hot summer in 2006

1. Pluto and dwarf planets; astronomical hot summer in 2006 ARIMOTO Jun’ichi (Kyoto Municipal Tohnan high school)

2. Overview The definition of the planet was settled in last summer, and Pluto excluded from the planet. In Japan, working group about the name of the solar system bodies was set up in Science Council of Japan, and Japanese name of the new category was decided. I report discussions in this working group, the reactions of the mass communications in Japan and correspondence to the school and public education.

3. Contents • IAU Resolution • Reactions in Japan • Working Group in Science Council of Japan • Reports of Working Group • Comments • Outreach scientific contents in the society • Correlation with a Japanese school curriculum

4. IAU Resolution: Definition of a “Planet” in the Solar System Resolution 5A The IAU therefore resolves that planets and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way: (1) A “planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit. (2) A “dwarf planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite. (3) All other objects, except satellites, orbiting the Sun shall be referred to collectively as “Small Solar System Bodies”.

5. IAU Resolution: Pluto The IAU further resolves: Pluto is a “dwarf planet” by the above definition and is recognized as the prototype of a new category of trans-Neptunian objects.

6. The reactions of the mass communications At last, Pluto “Disappears”!? From NHAO web site

7. The reactions of science textbooks in junior high school • The numbers of textbooks are 5. • It is described the Pluto in the text is 0. • It is described the IAU general assembly in the text is 5. • The conception diagram of the solar system was changed.

10. The most biggest orbit is Pluto. The distance of Pluto is about 6,000,000,000km of about 40 times of distance between the sun and the earth. Therefore, the solar system will open at least in the range of about a diameter of 12,000,000,000km. The most biggest orbit is Neptune. The distance of Neptune is about 4,500,000,000km of about 30 times of distance between the sun and the earth. Therefore, the solar system will open at least in the range of about a diameter of 9,000,000,000km.

11. Working Group in SCJ • About SCJ • The Science Council of Japan was established in January 1949 as a "special organization" under the jurisdiction of the Prime Minister for the purpose of promoting and enhancing the field of science, and having science reflected in and permeated into administration, industries and people's lives. Following are its two functions: • To deliberate on important issues concerning science and help solve such issues. • To make coordination among scientific studies to achieve higher efficiency. • Member of working group : 25 members • SCJ, Astronomical Society of Japan, The Japanese Society of Planetary Sciences, Society for Teaching and Popularization of Astronomy, Japan Public Observatories Society, Japan Planetarium Association, Amateur astronomer, Teacher, Mass communication,

12. Discussions in WG • Discussions in IAU • Reasonableness of new category • Definition of Dwarf planet is vague. • Trans-Neptunian objects is the most important concept in the new solar system image. • Japanese name of new category • It is translated from “dwarf” into “矮”. • A discriminatory meaning is included in “矮”. • Teaching and Popularization of new solar system image

13. Reports of Working Group • We don’t recommend the use of dwarf planet. • We named “準惑星”for dwarf planet. • We made commentary report for public, junior high school students and their teachers. • We will make poster of new solar system concept for public and students, and give out all schools.

15. Comment 1 • Outreach scientific contents in the society • The scientific essence does not readily come over, and it is taken up only of the surface topics. It is a problem very much that mass communication in particular lacks knowledge about science. In Japan, the environment that think about science as culture does not mature still more.

16. Comment 2 • Correlation with a Japanese school curriculum • By the Japanese curriculum, the astronomy is taught only with a junior high school third grader with a fourth grader. And Most students do not learn astronomy in the high school. Therefore many children and public can’t study the new knowledge about the solar system in such situation. This is a serious situation. I hope that Japanese curriculum will change better triggered by this disturbance. • Finally, I think that I and many teachers, astronomers, educator have to do for education more.