The Planet Walk begins with a sun that's 20 inches in diameter. At that scale, the Earth is 179 feet from the sun and the size of a pencil eraser. Jupiter, the largest planet, is 932 feet away and the size of a small orange. Lansing's River Trail winds through the model along the Grand and Red Cedar rivers. You'll stroll over five billion scale miles in less than an hour. The total walking distance on the trail is two miles. Your journey starts outside Impression 5 Science Center and ends near the Potter Park Zoo. With every footstep, you'll cover one million scale miles.