Sounds of the end times? via WNEP: If you live in or around Mifflinburg, you may have heard a very loud noise Sunday night. Many people in that part of Union County reported hearing a loud boom around 8 p.m. It only lasted for a second or two, but hundreds of people in Mifflinburg and surrounding areas heard it loud and clear. "Just a loud boom, and at the time, I thought it was thunder," Don Everitt said. "It was extremely loud, so much so that everyone said, 'Oh my God, it sounds like it's right outside my window. My house shook, and my windows shook,'" Mifflinburg Mayor David Cooney said. Cooney tells Newswatch 16 a large portion of the Buffalo Valley heard the boom. Many emergency agencies investigated but did not find anything. "Central dispatch did reach out to PPL to make sure there wasn't a very large line that exploded. They talked to air traffic control to make sure there wasn't a plane crash or something like that," Cooney said. Some people have theories as to what it was.