When It's Not Freezing, The Earth's Core Is Melting
Thursday, May 19, 2011 - 11:40
in Earth & Climate
The Earth's inner core is a ball of solid iron about the size of the Moon. This iron core is surrounded by a dynamic outer core of a liquid iron-nickel alloy - along with other, lighter elements - a highly viscous mantle and a solid crust that forms the surface where we live. That inner core is simultaneously melting and freezing due to circulation of heat in the overlying rocky mantle, according to new research . Over billions of years, the Earth has cooled from the inside out causing the molten iron core to partly freeze and solidify. The inner core has subsequently been growing at the rate of around 1 mm a year as iron crystals freeze and form a solid mass. read more