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Teaching Tips: What is a Planet?

What exactly is a planet? Is it size or composition or even its gravitational pull? Even the scientists cannot decide. Make your own decision by using these web sites. Included are eThemes resources on Pluto, the solar system, planetoid Sedna, and asteroids.


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Teachers can click on "How to use this story in a classroom..."
Read this article to discover how the debate continues about planetary definitions. NOTE: The site includes ads.
Learn about this spacecraft headed to Pluto. Find "Where is New Horizons" for computer generated images of New Horizons' path in the solar system. "Click here to play the launch video."
This astronomer has his own opinion on Pluto's new status.
Alan Stern writes an article about the many planetary bodies that are similar to Pluto.
Teachers can find an "Asteroid Fact Sheet" and "Frequently Asked Questions - Asteroids" and much more.
World Book Encyclopedia provides this information for NASA. There are videos and other interactive features under "Related Multimedia."
Look at this artist's rendition of UB313 otherwise know as Zena.
Download this two-page PDF file on the Kuiper Belt.
This information sheet can be printed out, find the "Print this" link. Browse the images of Pluto and Zena as well as the planetary montage.
These sites are about the solar system and the eight planets. Find out how much you weigh or how old you would be on different planets. Learn about the planets' different climates and structures. Includes simulations, videos, and photographs.
Learn about Pluto, the dwarf planet. Read how this dwarf planet was formed, its geological formation, and planned missions to Pluto. Students and teachers can read articles on Pluto's demotion to dwarf planet. Includes many photographs.
Learn how and when the new planetoid Sedna was discovered. Read about different theories and mysteries surrounding the planetoid and its hypothetical moon. Includes graphics, photographs, and an animation.
Learn about asteroids in the Asteroid and Kuiper Belts. Learn about history of their discoveries, their composition, and orbits. Find out what materials can be mined in the future on asteroids surfaces. These sites contain photographs, diagrams, coloring pages, a movie and worksheet.

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