Fictional planets of the Solar System 40 Eridani A. Counter-Earth was a hypothetical planet sharing an orbit with Earth, but on the opposite side of the Sun (hence Earth and Counter-Earth would always be invisible to each other). The idea of a counter-Earth has never been a serious scientific hypothesis in modern times. Phaëton is a name given to a supposed planet existing in the past between the orbits of Mars and Jupiter, which no longer exists, having become the Solar System's asteroid belt. Proposed not long after the discovery of multiple asteroids at the beginning of the 19th century, the idea that the asteroids were
Sagan Planet Walk Sagan Planet Walk The Sciencenter's Sagan Planet Walk is a walkable scale model of the Solar System, located in Ithaca, New York. The model scales the entire Solar System—both planet size and distances between them—down to one five billionth of its actual size. Consisting of eleven obelisks situated along a path through the streets of downtown Ithaca, the Planet Walk leads from the Sun at Center Ithaca to Pluto at the Ithaca Sciencenter. The exhibition was originally created in 1997 in memory of Ithaca resident and Cornell Professor Carl Sagan. In 2012, the model was expanded to include a representation