Published June 5, 2014 at 500 × 273 in NASA’s WISE Findings Poke Hole in Black Hole ‘Doughnut’ Theory Active, supermassive black holes at the hearts of galaxies tend to fall into two categories: those that are hidden by dust, and those that are exposed. Image credit: NASA/JPL-Caltech (Visited 15 times, 1 visits today)