Dwarf Planets of Our Solar System (Infographic) by Karl Tate In 2006 the organization responsible for classifying celestial bodies, the International Astronomical Union, decided that a new class of objects was needed. The solar system's erratic ninth planet, Pluto, was assigned to the new “dwarf planet” category along with four other bodies, all tinier than Earth’s moon. Some astronomers expect there may be as many as 50 dwarf planets in the solar system.
SC.5.E.5.2 - Recognize the major common characteristics of all planets and compare/contrast the properties of inner and outer planets. This activity is great for a class activity or an informal evaluation of the students. It sharpens the students' sorting skills, as well as comparing and contrast. Students will also demonstrate their knowledge of the difference between inner and outer planets throughout the activity, which can be use for informal assessments.