What would happen if the earth's core no longer remain hot and the magma cools and hardens inside the earth? Give reasons to support your answer.

If the Earth's core were to cool down and the magma inside the Earth were to cool and harden, it would have serious consequences.

1. The Earth's magnetic field, generated by the molten iron in the outer core, would weaken or disappear, leaving the surface exposed to harmful cosmic radiation.
2. Tectonic activity would halt, which could cause earthquakes and volcanic eruptions to cease. This will impact nutrient recycling. Over time, this could also lead to the formation of a supercontinent, as there would be no mechanism to break apart the continents.
3. Geothermal energy availability would be affected.
4. The Earth's rotation would slow down, leading to longer days and shorter nights. This would have significant effects on the climate and the seasons.