The Sagan Planet Walk scales the Solar System down to what fraction of its actual size?

The Sagan Planet Walk scales the Solar System down to one five-billionth of its actual size.

This walkable model in Ithaca, New York, represents both planetary dimensions and distances at the same 1:5,000,000,000 scale. The Sun station stands in downtown Ithaca, while the original route continues through a series of planetary markers to Pluto near the Ithaca Sciencenter.

The project was created in 1997 as a memorial to Carl Sagan, an Ithaca resident and Cornell professor. At this scale, Earth is only a few millimetres across, and the distance from the Sun to Earth is roughly 30 metres. The original path to Pluto is about 1.18 kilometres long, making the model’s vast distances tangible on foot.

The answer is sometimes confused with the scale of other planetary walks, which use different ratios. The Sagan Planet Walk was later extended to represent Alpha Centauri at the University of Hawaiʻi at Hilo, about 7,630 kilometres from Ithaca at the same scale.