With results that fundamentally differ from earlier black hole studies, Harvard researchers have shown that some recently discovered black holes are not only ultra-dense, but actually possess event horizons that “vacuum up” energy from their surroundings. “Watching matter flowing into a black hole is like sitting upstream of a waterfall and watching the water seemingly vanish over the edge,” said Ramesh Narayan, chairman of the Harvard Astronomy Department. The astronomers used NASA’s Chandra X-Ray Observatory to study some of the darkest black holes yet observed. They strongly confirmed the reality of the “event horizon,” the one-way membrane around black holes predicted by Einstein’s theory of relativity. The findings were announced by Michael Garcia, Jeffrey McClintock, Ramesh Narayan, and Stephen Murray of the Harvard-Smithsonian Center for Astrophysics and Paul Callanan of University College, Cork, Ireland.