Earth's inner core is solid and blistering hot. For decades, scientists have known the inner core is solid thanks to the pioneering work of Danish seismologist Inge Lehmann, who first proposed its ...

Our Earth is structured sort of like an onion – it’s one layer after another. Starting from the top down, there’s the crust, which includes the surface you walk on; then farther down, the mantle, ...

Our species likes it cold. Homo sapiens evolved in — and still inhabits — one of Earth’s rare and fragile ice ages, periods distinguished not by an abundance of saber-toothed cats and woolly mammoths ...