In Zeroth law of thermodynamics, it clearly says that the systems connected together are in thermal equilibrium.
My question is:
In Earth Science, scientists say that Earth's core temperature is 6000 °C, but the Earth's crust temperature is only 200 °C — 392 °C, why the temperature in Earth's crust, mantle, core aren't the same? It is stated in the law of thermodynamics that any system will have a thermal equilibrium when they are in contact, like thermometers if they get contact with us, we and them will have the same temperature, right?
But why earth's layers don't have thermal equilibrium? If scientists of geology were right, then thermodynamics is? If thermodynamics is right, then geology is? What is right? Law of Thermodynamics or geology? Because, if earth's layer will have a thermal equilibrium earth's core must not be at 6000 °C, or if earth's core is 6000 °C then earth's crust must be at 6000 °C also, right?