Pluto is now an official “dwarf planet” and is considered one of several large bodies that lie within the “Kuiper Belt” in the outer end of our Solar System.
On August 24, 2006 the International Astronomical Union redefined the classification of a planet. The new definition excluded Pluto as a planet, put it into the category of “dwarf planet”, gave it the number 134340, and put it on a list of “minor planets.”
Many of us still lament the loss of Pluto’s status as a planet. As a teacher, we use the whole process as a learning point. We talk about classification and that it is okay to change your mind or redefine something that was once considered a “fact”. It’s a good way to teach that Science is a constantly changing field and that we should not get too attached to ideas, but to always stay open-minded.