The next layer down is the mantle. When the Earth was young, Kimberlite pipes originated from the mantle, shooting up volcanic rock containing diamonds. The mantle is made up of solid peridotite. The two types of heat flow that occur within the mantle are conduction and convection:
As stated earlier, the core must be made up of metal because the Earth has a magnetic field and Earth’s surface layers are much less dense than Earth overall. Scientists know that the inner core is solid and the outer core is liquid because:
The lithosphere is about 100 km thick and is composed of the crust and the uppermost mantle. It behaves as a brittle, rigid solid. The asthenosphere is the part of the upper mantle that acts like a hot plastic and flows. The lithosphere rides on the asthenosphere.