Avid cyclists passing Mercury just southwest of Monona Terrace.

Cyclists passing the earth, just north of the Brittingham boathouse on Monona Bay.

What is it?
Planet Trek Dane County (PTDC) was a celebration of the International Year of Astronomy brought to you by UW Space Place and partners. PTDC was a temporary installation uniting science education, art, and outdoor recreation and was on display from April-October 2009. PTDC was, at heart, a scale model of our solar system: We shrunk the Sun, planets, and other bodies by the same factor so that the sizes and distances were represented to scale relative to each other. In our model, the scale was about 200 million to 1. This means the Sun was a sphere about 24 feet in diameter at Monona Terrace, and Pluto the size of a marble in Mt. Horeb.

Where is it?
The PTDC Sun was located at Monona Terrace Convention Center in downtown Madison. Your trek through the solar system followed the Southwest Commuter Bike Trail, then the Military Ridge Bike Trail. PTDC ended at Pluto, which was located about 23 miles away from Monona Terrace in the village of Mt. Horeb. Here's a scalable map of the route.

Who can ride it?
All parts of PTDC were open to the public. You could voyage anywhere from the Sun to Saturn (just west of Midvale Blvd. on the bike path), on foot or bicycle whenever you like. Uranus and points beyond required access to Military Ridge Trail, which requires purchase of a trail pass from the Wisconsin DNR.

When can I see it?
The installation was on display until October 2009. Look for it again in the spring of 2010.

Tell us about your trek!
You can leave still comments on our blog.