Question

How long is the earth's core?

Answer 1

The depth rather.

`2250` `km` is the outer core's depth and the radius of the inner core is about `1300` `km`.

Explanation:

The two lighter part are the inner and the outer core:

http://discovermagazine.com/2013/jan-feb/20-things-you-didnt-know-about-inner-earth