Published February 28, 2013 at 1400 × 933 in NASA’s NuSTAR Helps Solve Riddle of Black Hole Spin Two Models of Black Hole Spin. Scientists measure the spin rates of supermassive black holes by spreading the X-ray light into different colors. Image credit: NASA/JPL-Caltech (Click image to enlarge) (Visited 11 times, 1 visits today)