This detailed essay defines planets and compares the characteristics to those of Pluto. Orbital graphs and background information clarify the change in Pluto's categorization. A copy of IAU's Resolution 5 is also contained in this essay.

Read about the atmosphere of Pluto.

This site contains copious information about Pluto. The site contains descriptive and statistical information, as well as a detailed article about the search for trans-Plutonian planets and the "Nemesis" hypothesis.

Find out about how planets have been classified historically, and what scientists use to study them.

In this simple lesson, students grow yeast to learn how the climates on each of the nine planets would affect life.

Learn fun facts and details about the atmosphere, geography, composition, and discovery of Pluto, a dwarf planet.

Until the discovery of Eris, Pluto was known as the largest Keiper belt object. This dwarf planet has replaced Pluto in size and is accompanied by a satellite that has been given the name Dysnomia. Learn about this distant world here...

Students explore the outermost planets of our solar system: Saturn, Uranus and Neptune. They also learn about characteristics of Pluto and its interactions with Neptune. Students learn a little about the history of space travel as well...

These hands-on activities are a great way for students to gain perspective on the relative sizes and distances of each planet, the relationship between the sun and Earth, and much more.

Find out about Clyde Tombaugh, the scientist who discovered the dwarf planet Pluto in 1930, and also discovered a number of asteroids.

The innovative resource examines images of the Sun, Moon, Pluto, and all eight planets in the Solar System. Learners calculate the diameter of each object and rank the objects in order of size. The activity has an interactive online...