The Earth is believed to have four layers - crust, mantle, outer core and inner core. Now scientists have found
About Australian Geophysicist ResearchJoanna Stevenson National University and her colleagues write Popular Mechanics. Scientists have found evidence that the Earth's inner core can be made up of two different layers. If the discovery is confirmed, it may even require rewriting textbooks, the researchers say.
Scientists used an algorithm to comparethousands of inner core models with seismic data. The researchers saw that seismic waves change direction by 54 degrees as they pass through the Earth. Those waves that moved faster passed parallel to the axis. Scientists considered this to be evidence that the structure of the iron had changed in the nucleus. The researchers hypothesized that there were two distinct cooling periods in Earth's history.