WELLINGTON, New Zealand - A sonic boom rattled southern New Zealand on Tuesday, and hundreds of callers swamped emergency services about the noise, which scientists said was probably caused by a small meteor plunging toward earth. Residents in the southern city of Christchurch, 190 miles south of the capital Wellington, told police and fire services that the boom shook the ground and their houses. The resident superintendent of the Mt. John Observatory, Allan Gilmore, told National Radio the sonic boom indicated the meteor was traveling "very low" and was probably between the size of a baseball and a basketball. Witnesses...