Earth’s inner core may be more complex than researchers thought

Seismic waves suggest that the planet has a hidden heart

An illustration of Earth's center with lines running through it from on overlay map of North America.

Powerful earthquakes, such as one that occurred in 2018 in Alaska, can send seismic waves reverberating through Earth’s center (illustrated). Such waves reveal an innermost layer to the inner core, researchers say.

Drew Whitehouse, Son Phạm and Hrvoje Tkalčić

Earth’s heart may have a secret chamber. The planet’s inner core isn’t just a solid ball of nickel and iron, researchers say, but contains two layers of its own: a distinct central region nestled within an outer shell.