It takes a rather long time for heat to move out of the earth. This occurs through both "convective" transport of heat within the earth's liquid outer core and solid mantle and slower "conductive" transport of heat through nonconvecting boundary layers, such as the earth's plates at the surface. read more
The earth's core is divided into two separate regions: the liquid outer core and the solid inner core, with the transition between the two lying at a depth of 5,156 kilometers (3,204 miles). read more
I have heard that the Earth is made up of four layers, being the crust, the mantle, the outer core and the inner core. I have also heard that the Earth's temperature increases as you move from the crust to the inner core, with the inner core having a temperature of 4700 degrees. read more
So we have an inner core that is solid and an outer core that is liquid. Together they are over 2000 miles in radius, or around half the size of the entire planet. Above the core is the thick mantle, and on top of that is a relatively thin crust, which is just under our feet. read more