A mysterious shiny object floating high over Manhattan's West Side set off a flurry of reports and wild speculation Wednesday that a UFO was flying over the city. Police and the FAA said they began getting flooded with calls starting at 1:30 p.m. from people reporting a silvery object hovering high over Chelsea. Law enforcement sources said they believed the object was likely some sort of balloon, but as of late Wednesday they had not confirmed exactly what it is. A Daily News reporter could see a tiny, silver dot floating approximately 5,000 feet above 23th St. and Eighth Ave., where dozens of people gathered late in the afternoon to catch a glimpse. "It's been hovering there for a while. I'm just kind of baffled," said Joseph Torres, 49, of Dyker Heights, Brooklyn, who spotted the object after leaving a movie. "How can it be ordinary? There is something going on."