Shadow Rings

A sculpture in Florida that looks like an alien metallic flower will cast a shadow around a plaque today. The plaque commemorates the possible first sighting of Florida by European explorers, on this date in 1513.
The sculpture is named “Solar Rotary.” It’s on the campus of the University of Southern Florida in Tampa. It’s one of many sculptures around the country that have special solar alignments.
One is the Soleri Bridge in Scottsdale, Arizona. It’s a pedestrian bridge with tall pylons at its end. The Sun shines through a narrow gap between the pylons at certain times, lighting a stripe on the bridge. The pylons cast no shadow at noon on the summer solstice.
Another, in Honolulu, is called Sky Gate. It’s a wavy ring atop three legs. The Sun stands directly above it at local noon on two dates each year. At those moments, the sculpture casts a perfectly round shadow on the ground below.
Solar Rotary was created by artist Nancy Holt. A campus astronomer calculated the site’s precise la