Both Radioactive dating of rocks retrieved from the world and Comparing cratering rates on one world to those on another.
Geologists can find the relative age of impact craters on a world because
the ones on top must be younger.
Scientists know the history of Earth's magnetic field because the magnetic field gets frozen into rocks, and plate tectonics spreads them out.
Hope it helps
Answer:
Viscosity directly affect the speed of convictions.
Explanation:
The speed of convection in Earth’s mantle, oceans, and atmosphere also depends on the viscosity of the fluids. If the viscosity of fluids is higher so it takes more time to complete the process of convection in Earth’s mantle, oceans, and atmosphere, while on the other hand, if there is lower viscosity of fluids, the conviction in the mantle, oceans, and atmosphere of earth occur in high speed due to easily movement from place to place.
I think I might be a LITTLE later on this one... but it was recommended, it's Deutschland