... Earth is the third planet from the Sun and the fifth largest: orbit : 149,600,000 km (1.00 AU ) from Sun diameter : 12,756.3 km mass : 5.972e24 kg . ... 0- 40 Crust 40- 400 Upper mantle 400- 650 Transition region 650-2700 Lower mantle 2700-2890 D'' layer 2890-5150 Outer core 5150-6378 Inner core The crust varies considerably in thickness, it is thinner under the oceans, thicker under the continents. The inner core and crust are solid; the outer core and mantle layers are plastic or semi-fluid. ...