Ultrafast black holes.

Black holes stir up ripples in spacetime as they merge. The work gives insight into to the energy that black hole mergers release. Colliding black holes can launch newly melded cosmic sinkholes at speeds up to nearly 10 percent of the speed of light, or about 28,500 kilometers per second, scientists at the Rochester Institute of Technology in New York report in the Aug. 18 Physical Review Letters. [Extracted from the article]