Which layer of the Earth is known to be the densest?

The inner core is recognized as the densest layer of the Earth primarily due to its composition and the immense pressures present at that depth. The inner core is made predominantly of iron and nickel, metals that are much denser than the materials found in the outer layers of the Earth, such as the crust and mantle, which contain a higher proportion of less dense silicate minerals.

As you move toward the center of the Earth, both pressure and density increase significantly. The inner core experiences pressures exceeding three million times that at the surface, which contributes to its solid, dense state despite the high temperatures. This combination of metal composition and extreme pressure is what makes the inner core the densest layer of the Earth, distinguishing it from the outer core, mantle, and crust, which are less dense.