The layer just outside the center of the Earth is the outer core.

Here's a breakdown of Earth's layers from the center outwards:

* Inner Core: A solid ball of mostly iron with some nickel.

* Outer Core: A liquid layer of iron and nickel.

* Mantle: A thick layer of mostly solid rock, but it behaves like a very viscous fluid over long periods.

* Crust: The thin, outermost layer of solid rock.