Earth core temperature is range between 4,400° Celsius (7,952°
Fahrenheit) to about 6,000° Celsius (10,800° Fahrenheit).
Why can't the Earth's core melt the whole planet? In other words, what is stopping Earth from being melted up to its surface?
[Physics] Why can’t the Earth’s core melt the whole planet
earthestimationgeophysicstemperaturethermodynamics
Best Answer
Think about a frozen-over lake in the winter. The water underneath is liquid, but it doesn't melt the ice. In fact, it wasn't even able to stop the ice from freezing as the weather got colder in the winter. The surface of the lake was losing heat faster than it could soak up heat from the warmer water below, so it froze while the deeper water was still liquid.
The earth was completely molten right after the impact that formed the moon. That's like the lake at the end of fall. The liquid surface radiated heat away into space until first the surface solidified (pretty quickly) and then the depth of solid rock got greater and greater. The hotter molten rock down below just couldn't heat up the surface fast enough to keep it molten.