Astronomers using an automated telescope that scans 10 million stars and galaxies a night have discovered a mysterious flashing light in the Big Dipper. It flashes like a slowly rotating searchlight, they say.?It’s a mystery,’ said Los Alamos researcher Jim Wren. ?It’s definitely a strange object.‘The cosmic lighthouse  was spotted March 29 by the Robotic Optical Transient Search Experiment at Los Alamos. It brightens, then dims and brightens again in a cycle, Wren said.Ron Remillard of Massachusetts Institute of Technology was the first to see it. He sent out a request for corroborating observations and received a response from Japan within an hour that scientists there saw it, too.Remillard theorizes the pulsing may come from a black hole, a dying star with a force of gravity so intense that not even light readily escapes its pull. He said the black hole, perhaps on the fringes of our galaxy, may be sucking dust and gas which heats as it spirals to its death, giving off the pulsing light and X-rays.