>>11451556>How came that Earth was able to preserve a hot liquid interior unlike Venus and Mars?The two big theories that I've heard are that the Earth has liquid oceans, and the Moon's gravity are the reason. The oceans help break up and lubricate tectonic plates which allows for the Earth's interior to be more thoroughly stirred. The Moon's gravity tugs on the interior of the Earth (i.e. tidal forces) which converts gravitational energy into thermal energy within the Earth.
>As far as my understanding goes, the two main factors that keep Earth's interior hot is tidal forces and radioactive decay. Which one is playing major role?I think it's the tidal forces.
>Is there any explanations why is Earth so dense?A hypothesis I've heard is that the collision with Thea in Earth's past caused the dense cores of the two planets to merge (mostly) while blowing away the lighter material.
