Inner core

Earth’s interior

The inner core is a solid iron-rich sphere with a radius of about 1,221.5 km. Despite temperatures comparable to the Sun’s surface, enormous pressure keeps it solid. Its growth releases heat and light elements into the liquid outer core.

html,body{position:static!important;height:auto!important;overflow:auto!important}body{color:#e8f1ff}body>:not(noscript){display:none!important}#static-seo-content img{display:block;max-width:100%;height:auto}#static-seo-content{max-width:800px;margin:40px auto;padding:24px;font:16px/1.7 Arial,sans-serif}#static-seo-content a{color:#a8d5ef}#static-seo-content nav{display:flex;flex-wrap:wrap;gap:12px} Earth’s interior: Crust · Upper mantle · Lower mantle · Outer core · Inner core · Innermost inner core (IMIC)

Earth’s interior: Crust · Upper mantle · Lower mantle · Outer core · Inner core · Innermost inner core (IMIC)

Inner core

The inner core is a solid iron-rich sphere with a radius of about 1,221.5 km. Despite temperatures comparable to the Sun’s surface, enormous pressure keeps it solid. Its growth releases heat and light elements into the liquid outer core.

Beneath the seafloor NASA · Earth