It’s not easy being a planet. For one thing, unless you’re Earth, it’s pretty lonely out there in the solar system. Sure, Mars is getting all the attention these days with some incredibly impressive visitors. But as red-hot as Mercury is, there’s not much going on. Saturn’s got rings, but no medals or awards. And Pluto? Poor Pluto. Discovered on February 18, 1930, Pluto’s very planetary existence was in a sort of limbo until 2006. That’s when it got the boot.
To be a planet, the International Astronomical Union says an object has to
orbit around the Sun
have sufficient mass to assume hydrostatic equilibrium (be a nearly round shape)
have “cleared the neighbourhood” around its orbit
Poor Pluto hasn’t managed to clear all the other junk out of its odd orbit.
Today would be a good day to have a Pluto scavenger hunt. If your students have access to computers to do research, have them scour the Internet to find out something interesting about Pluto. A trip to the library would work too. Better yet, have them write a short speech written from Pluto’s point of view in which the dwarf planet reacts to being “demoted.” Stop by TheMailbox.com for additional FREE ideas for studying the planets.