Probing the core's light elements

摘要

Earth's core accounts for one-third of the planet's mass and has a central role in Earth's overall energy budget and dynamics. Although the core has long been known to be composed mainly of iron, together with some nickel, the identity of the lighter elements that make up about 8% of the core's mass has been an enigma for nearly 60 years. Work reported in this issue by Huang et al~.3 (page 513) combines the results of laboratory experiments with geophysical data for the core to address this long-standing mystery. Better knowledge of the core's main light element (or elements) will shed light on heat flow in Earth's deep interior, on the origin and growth of the core's solid inner region, and on the generation and evolution of Earth's magnetic field.