Why is the center of the earth molten iron and not heavier metals, such as gold?

Question

I would assume heavier molten metals would be in the center of the earth. Is it possible that the center has different molten metals on top of each other with a high concentration of iron on the outside of the core?

In: 2513

Answer 1

The gold that was on the planet when it formed mostly did end up in the core. Iron is just the most common heavy element, so the core is mostly made of it.

The reason iron is so common is that nuclear reactions want to turn light elements heavier and heavy elements lighter, and iron is the lightest element that doesn’t want to turn heavier. So stars, which start with light elements like hydrogen and helium, can build iron or anything lighter than it without spending extra energy. Whereas anything heavier than iron costs a star energy to make.