Heyn, in action in Baltimore's Fells Point with that night's feature attraction: Jupiter's moons. Kevin and Sonia McCarthy/Courtesy of Herman Heyn hide caption

itoggle caption Kevin and Sonia McCarthy/Courtesy of Herman Heyn

Shaun Harper of the University of Pennsylvania is a co-author of the new report. Stuart Goldenberg/University of Pennsylvania hide caption

itoggle caption Stuart Goldenberg/University of Pennsylvania

A human skeleton, part of the WM Bass Donated Skeletal Collection. Elissa Nadworny/NPR hide caption

itoggle caption Elissa Nadworny/NPR

A mural dedicated to Freddie Gray remains in the Sandtown neighborhood of Baltimore where he was arrested in May of this year. Gray's later death in custody sparked days of unrest in the city — and, now, has inspired a course at the University of Maryland law school. Andrew Burton/Getty Images hide caption

itoggle caption Andrew Burton/Getty Images