Hey inner core, how old are you?
Earth’s core is predominantly composed of iron alloyed with some light elements. Core’s thermal conductivity determines its thermal evolution (including the age of inner core) and dynamics of Earth’s magnetic fields. Dr. Wen-Pin Hsieh of the IES high-pressure mineral physics laboratory has measured the thermal conductivity of iron and iron-silicon alloys at core’s high pressure-temperature conditions. His team demonstrated the thermal conductivity of iron-silicon alloy is much lower than previously thought. Combined with numerical modeling, they further found that the low thermal conductivity of core substantially delays its cooling, suggesting that the inner core could be older than two billion-years. Moreover, the thermal energy alone released by the core could sustain the operation of geodynamo. The international research team includes Drs. Wen-Pin Hsieh and Frédéric Deschamps of IES and Prof. Jung-Fu Lin of University of Texas at Austin, etc. These results are recently published in Nature Communications https://www.nature.com/articles/s41467-020-17106-7.
