Black holes take light for a spin

Newly discovered effect could aid observations of Milky Way's monster

Given how weird black holes are, it’s only fitting that researchers have found a screwy way to detect the rotation of these gravitational monsters. Existing telescopes could be equipped with special detectors to record the twist imprinted on light waves that pass near a rapidly spinning black hole, Bo Thidé of the Swedish Institute of Space Physics in Uppsala and his colleagues report online February 13 in Nature Physics.