The zone of rocks just outside Earth's core could hold enough water to fill the oceans five times. That's the indication from an analysis of minerals created in the laboratory under conditions that simulate those deep within the planet.
Scientists believe that Earth's core is primarily iron with a smattering of silicon (SN: 1/12/02, p. 22: Earth's inner core could include silicon). The lower portion of Earth's mantle–the layer of hot, viscous rocks between the core and the cooler crust–is thought to be made up mostly of silicate minerals, which include silicon and oxygen.
Recently, geologist Kei Hirose of the Tokyo Institute of Technology and his colleagues mixed up blends of elements that, when heated under intense pressure, transform into the three most common minerals in Earth's lower mantle. After cooking each batch of ingredients at 1,600C for more than an hour under a pressure equal to 250,000 times that of the atmosphere at se