This interactive feature lets students compare the sizes of the planets in our solar system. Users can select two solar system bodies (planets, Sun, Earth's moon) and view side-by-side images at the same scale, along with their diameters in kilometers or miles, and a ratio. Science NetLinks is part of MarcoPolo, a partnership between the Verizon Foundation and eight premier educational organizations. The MarcoPolo partnership provides free, Internet-based content across academic disciplines. Science NetLinks is managed by the American Association for the Advancement of Science (AAAS) and its role is to provide a wealth of standards-based resources for K-12 science educators, including lesson plans, interactives and reviewed Internet resources.