A new Arizona footbridge doubles as a walkway and a solar calendar.
Lunch at noon? Yes, but when is that, precisely? True noon—solar noon to be exact—is the moment when the sun reaches the highest point in its daily trip across the sky. Paolo Soleri, the visionary Italian-born architect, seized on the sun’s diurnal and seasonal cycles and built them into Soleri Bridge, a stylish span in Scottsdale, Ariz., that’s both a footbridge and a solar calendar.
At solar noon each day, a sliver of sunlight breaks through a six-inch gap between two 64-foot brushed-steel pylons at the bridge’s south end, piercing the shadows cast by the towers. The shadows lengthen day by day as winter deepens, then shorten toward summer and disappear altogether on the year’s longest day, the summer solstice.
The 91-year-old Soleri is renowned for his concept of “arcology,” which melds architecture and ecology, and for Arcosanti, his utopia in progress in the Arizona desert. Of dozens of bridges he has designed, the Scottsdale span is the first built. (480) 889-2711, scottsdalepublicart.org .
Photography by Bill Timmerman 
This article was first published in March 2011. Some facts may have aged gracelessly. Please call ahead to verify information.