Earth is thought to have arisen from a cloud of gas and dust in space.
Bombarding planetesimals heated Earth to a molten state. The heat energy produced by Earth is enormous, but it's 5000 times less than what Earth receives from the sun. The sun's heat drives the weather and ultimately causes erosion. So while Earth's heat builds mountains, the sun's heat destroys them. With thanks to the National Science Foundation , we're Block and Byrd for Earth and Sky.