Issue 50 / June 9, 2016Editor's Note from June 09, 2016Issue 50: Lightning bugs, beating hearts, and golden spirals. / Ted Olsen The Most Spectacular FireflyWe’re drawn to animals that shine their own light. For one, it’s a group effort. / Julie Sumner Mysteries of a Beating HeartWe don’t really know how a heartbeat sparks to life. / Lindsay Stokes The Eagle, the Shell, and the SunflowerThe Golden Spiral appears all over nature. / Joel Bezaire Bright Angels“When I was growing up, / they were lightning bugs.” / Ronnie Sirmans Wonder on the WebIssue 50: Links to amazing stuff.