An international team of researchers has discovered a curious feature of the jet of material produced by V404 Cygni, a stellar-mass black hole in the Milky Way. The jet wobbles in periods that can be as short as a few minutes. This happens because the black hole's gravity is dragging space-time around the jet. As reported in Nature, such a rapid wobble has never been seen before in systems like this. V404 Cygni weighs nine times the mass of our Sun and is almost 8,000 light-years from Earth. It has a companion star, which is slightly smaller than the Sun, and the black hole steals material from it. This material swirls around the black hole forming a structure called an accretion disk. The part of this disk closest to the black hole is denser and hotter than the rest of it and either this or the black hole itself sends bits of material flying into a jet at 60 percent of the speed of light. The spin of the black hole and the plane of the disk are not aligned. Because of this, as the