The outer core of the Earth is a liquid layer about 2,266 km (1,408 mi) thick composed of iron and nickel which lies above the Earth's solid inner core and below its mantle. Its outer boundary lies 2,890 km (1,800 mi) beneath the Earth's surface. The transition between the inner core and outer core is located approximately 5,150 km (3,200 mi) beneath the Earth's surface.
I’ve been receiving questions from you people for years now – and really, this made me happy, because it says that people want to learn and understand more. But I’ve been answering them individually, and now, I’m thinking it would be better to post the answers on the website, so more people can read them. [...]
The great part of Earth’s liquid outer core comprises of molten iron, which is just swell for us and every inhabitant of our planet, because this layer generates a magnetic field which protects us from radiation which would be lethal. But common accepted theory suggests that there should also be some lighter ingredients down there, [...]