Tour the Solar System! In November of 1997, a unique, educational monument and memorial was dedicated. Built by the Sciencenter to honor Ithaca resident, astronomer, and Cornell Professor Carl Sagan, the Sciencenter's Sagan Planet Walk is a scale model of the Solar System in the midst of the City of Ithaca. The model starts with the sun at the center of the Downtown Ithaca Commons and stretches north to the Sciencenter ending with the station representing the dwarf planet Pluto, 3/4 mile, 1.2 km away. On the Discovery Trail.