Why is the earth's interior so hot? leftover heat from formation and radioactive decay solar energy heats the crust convection currents cause it to heat up magma heats the core

The Earth's interior is primarily hot due to the residual heat left over from its formation over 4.5 billion years ago. As the planet formed, energy from the collision of particles and the compression of materials generated intense heat. Additionally, the decay of radioactive isotopes, like uranium and thorium, contributes to maintaining that heat, creating a warm, molten environment deep within the Earth. On a practical level, this intense heat plays a crucial role in powering geological processes like volcanic eruptions and plate tectonics. The movement of molten rock, or magma, not only shapes the landscape but also affects seismic activity, leading to both the creation of mountains and the occurrence of earthquakes. This geothermal energy can even be harnessed for clean energy sources.