Earth Science

The Earth, with outer and inner core shown

The Earth is layered.  The outermost layer is the crust, which is a thin layer.  Oceanic crust is ~30 km thick and continental crust ~70 km thick.  Beneath the crust is the mantle, which can be further subdivided, extending down to about 2880 km depth.  At that depth we encounter the liquid outer core, which has a radius that is 55% of the Earth's total radius.  The inner core (solid) is then at 5155 km depth.

The Earth's radius is 6371 km.
The outer core, red, is 3482 km in radius.
The inner core, yellow, is 1216 km in radius.

© 1999