Pluto used to be the ninth planet in the solar system. For a while it was the eighth planet. Now Pluto has been demoted and is no longer a planet at all.You can read the official announcement made in 2006 and see that there are three criteria for planethood, and Pluto hasn’t met them all.
Some people are taking this hard. Explore the reactions and responses with these online resources:
- Poor Pluto! by Mathias Pedersen shows tiny Pluto being cruelly shunned by the remaining planets. You can download the image as wallpaper for your classroom computer while you study the topic. You can also use clay to recreate the scene for your display table, incidentally reviewing the planets of the solar system.
- Pluto Reinstated? by J. Major is a readable essay which should provide good reading and discussion practice for middle school and up.
- The Society for the Preservation of Pluto as a Planet is trying to have Pluto reinstated. Read thoughts on both sides and hold a vote.
Now that you’ve gotten that out of the way, you can still study Pluto:
- A very simple page on Pluto introduces the former planet to young students. Set this page up at your computer center and show students where to click (upper left corner) to hear the page read aloud.
- Latest news from NASA on the expedition to Pluto’s neighborhood, New Horizons.
- A fact sheet from NASA compares Earth and Pluto with lots of interesting numbers. The chart includes ratios. Have pairs of students pick one or two of the metrics included and figure out how to understand them completely. Once they’ve completely grasped ellipticity or comparative gravity, each pair can explain it to the class. Once the class gets a handle on all this data, we bet they can make a better graphic organizer than NASA did!
One of the interesting things about Pluto is that a child suggested the newly discovered object be named after Pluto, the Roman god of the underworld. Read a story about Pluto (Hades in Greek Mythology) in our Demeter and Persephone Lesson Plans after you’ve learned about the nature of Pluto, and see whether you agree that Pluto is a good name for this dwarf planet.