Whatever it was, the boom shook walls and swayed chandeliers."It sounded like a plane had crashed," said Fred Krauer Jr., 43. The noise rattled every room in his home north of State Road 52 and west of Hicks Road. "I felt it in my feet in the shower."He rushed outside. There were no flames or smoke, just another overcast day in Hudson.A massive boom shook homes across Pasco, Hillsborough and Polk counties around 1:45 p.m. Saturday. Residents called government hotlines, and theories swirled online. Could it be military operations? An explosion? A meteor? Supersonic jets?Half a dozen government agencies all had the same answer Saturday: We donít know, but we didnít do it.Pasco County spokeswoman Tambrey Laine said dispatchers got dozens of calls.Tampa Bay is surrounded by military bases and has a long history of mysterious booms often attributed to military tests. But MacDill Air Force Base said it wasnít them. So did Eglin Air Force Base at the edge of the Florida Panhandle, Tyndall Air Force Base in Panama City, and the Space Coast-based 45th Space Wing and Kennedy Space Center."We have no records of fighters in the area," said Terry Montrose, spokesman for the 6th Air Mobility Wing, based at MacDill. He said the base received about a half-dozen calls about the booms."Itís a little unnerving, as with anything with the unknown," said Krauer, an Army infantry veteran. "If we donít have the answer for something, your mind starts reaching."There was one possible explanation: Two F-15 fighters were given permission by NORAD to fly at supersonic speed ó in excess of 760 mph ó over the Gulf of Mexico, said Canadian Air Force Lt. Marco Chouinard, a NORAD spokesman.NORAD is the North American Air Defense Command, an organization of the United States and Canada that provides aerospace warning, air sovereignty and protection for Northern America.The jets were not responding to any incident, Chouinard said. There was no way to be sure they caused the noise, he said.