A bright light that streaked across skies over the Southwest prompted hundreds of calls to safety agencies, but officials were unable to explain the phenomenon. The object, which officials said could have been a meteor, was seen from Arizona to California and south of the Mexican border just before 9 p.m. Monday. "It was described as something on fire, like a ball of fire in the sky," said Martha Pfrommer, a dispatcher with the California Department of Forestry in Riverside. "Apparently everybody was reporting it as a plane crash." Beth Kilgore, a spokeswoman for the North American Air Defense Command in Colorado Springs, said the light did not stem from any man-made object such as a satellite or missile.