Sagan Planet Walk

42°26′23″N 76°29′56″W / 42.4396966°N 76.498887°W / 42.4396966; -76.498887

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. The exhibition was originally created in 1997 in memory of Ithaca resident and Cornell Professor Carl Sagan.^[1]

Consisting of eleven obelisks situated along a 1.18 km (0.73 mi) path through the streets of downtown Ithaca, the original Planet Walk leads from the Sun at Center Ithaca to Pluto at the Ithaca Sciencenter. In 2012, the model was expanded 7,630 kilometers (4,740 mi) to include a representation of Alpha Centauri, the Sun's closest neighboring star, at the ʻImiloa Astronomy Center at the University of Hawaii. The addition of the Alpha Centauri Obelisk made it the world's largest exhibition,^[2][3] until the Akaa Solar System Scale Model added Proxima Centauri in 2018 at a distance of 13,370 kilometres (8,310 mi) away from Akaa.

In 2014, the inner planets and Sun were removed as part of extensive construction being done to the Ithaca Commons, but have since been replaced. In 2015, a grant was approved to further expand the exhibition by installing an exoplanet Kepler-37d station on the Moon 384,500 kilometers (238,900 mi) away.^[4][5]