Galaxy M87 jets, Chandra X-ray image. M87 is an elliptical galaxy that is about 50 million light years away from Earth. It has a supermassive black hole at its core which gathers infalling material and produces powerful jets that launch energetic particles outwards. The jets contain clumps or knots (bright areas). A knot that researchers observed in 2012 (left inset), when observed in 2017 (right inset), had moved away from the black hole and faded significantly. By measuring how far the knots had moved over this time, researchers calculated the speed of the jet streams as being close to 99% of the speed of light.