An apparent meteor passing through the atmosphere just east of Boston caused a loud boom heard over multiple areas of Massachusetts around 2 p.m. on Saturday, according to Ken Mahan, lead meteorologist for the Boston Globe. “It’s a bolide meteor, which is essentially a fireball,” Mahan said. “These are large and often spark a sonic boom when passing through the atmosphere with speeds faster than the sound barrier and air compressing ahead of the meteor as it races through, generating a massive pressure wave.” “The average size bolide meteor sits at 1-2 meters,” he added. “NASA will ultimately estimate the size of this meteor in the coming days.”