<em>it took <u>130 years </u> to build Sagrada familia... :) it build from <u>1852 to 1926...</u>
</em>
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
Plates at our planet's surface move because of the intense heat in the Earth's core that causes molten rock in the mantle layer to move. It moves in a pattern called a convection cell that forms when warm material rises, cools, and eventually sink down. As the cooled material sinks down, it is warmed and rises again.
Canada was under British rule beginning with the 1763 Treaty of Paris, when New France, of which the colony of Canada was a part, formally became a part of the British Empire.
