The earth is made up of many layers (the crust
is the outside part we live on, the mantle is the
middle and the core is at the center). The core is
the most dense part.
The core and mantle used to be one continuous lava
(which we call magma), but over millions of
years, the core separated from the mantle.
When you put dust or dirt in a glass of water, it
starts off my mixing, but eventually the heaviest
pieces sink to the bottom. This is what happened
to the core and mantle over millions of years--
the heaviest elements separated and accumulated
together to form the core. This is why the
core is more dense than the mantle.
Why does it orbit
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