Researchers have observed a newly discovered innermost core of the earth. Seismic station see up-to-fivefold reverberating waves from selected earthquakes along the Earth's diameter. Differential travel times of these exotic arrival pairs complement and improve currently available information. There is ~650-km thick innermost ball. Dr. Tkalcic and Thanh-Son Pham, a postdoctoral researcher, estimate that the innermost inner core is about 800 miles wide; the entire inner core is about 1,500 miles wide. The innermost inner core is a solid 'metallic ball' that sits within the centre of the inner core.