While the demotion of Pluto to the status of “dwarf planet” makes perfect sense to some scientists and outrages others, it also provides teachers around the world a wonderful opportunity to engage students in lively discussions that will expose them to astronomy, scientific debate and the very strange nature of the outer solar system.
Pluto has always been different from what we used to think of as its eight siblings (Perhaps now they are just distant cousins). Pluto is small and also has an elliptical orbit that sometimes made it the eighth planet from the Sun.
Its new status will be difficult to accept for many of those who have spent their entire lives thinking of the solar system in terms of nine planets, but the discovery in recent years of objects far from Pluto that are also larger forced scientists to re-think the definition of what constitutes a planet in this solar system. That is how scientific research works. It is never static and always evolving.
Such distinctions as these are not trivial. It is worth wondering what might have happened to NASA’s Pluto flyby mission if Pluto’s reclassification had happened earlier. Would Congress have felt the same urgency to fund the mission after NASA moved repeatedly to cancel it?
We will never know, but fortunately Congress made the right decision. Pluto’s reclassification shows that we are only beginning to understand the outer solar system and the Kuiper Belt where many scientists believe it is possible we might one day find dozens or hundreds of objects the size of Pluto or larger. The New Horizons probe now en route to Pluto and its Kuiper Belt neighbors clearly will not be the culmination of our exploration of the solar system. It is only the beginning.