Final answer:
The Earth's outer core is a liquid layer of molten iron, nickel, and sulfur, starting at 2900 km depth, which is essential for generating Earth's magnetic field.
Step-by-step explanation:
The Earth's outer core begins at a depth of approximately 2900 kilometers beneath the surface and extends to the inner core. This layer is composed of a molten mixture of iron, nickel, and sulfur, which contributes to its high density. Unlike the inner core which is solid, the outer core is in a liquid state and plays a crucial role in the generation of the Earth's magnetic field. The outer core is about 2300 kilometers thick and because of the intense pressure and heat, it has a unique property of flowing, which aids in the convection process responsible for the dynamo effect that maintains our magnetic field.