ELI5 what is the core of the Earth made of, how does it stay molten, and what would the impact of it cooling be?

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ELI5 what is the core of the Earth made of, how does it stay molten, and what would the impact of it cooling be?

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It has a solid iron and nickel core surrounded by a liquid outer core mostly of the same metals. It stays molten due to the immense pressure of all the mass above it, generating heat.

The liquid core is believed to be the source of the planet’s magnetic field. If you were to magically cool it and harden it, the planet would lose much of its magnetic field which would expose the surface to significantly more solar radiation, likely resulting in the planet becoming much less if at all habitable.

As best scientists can currently tell, the core is made up of a nickle-iron alloy. There is a solid inner core and a liquid outer core.

The liquid outer core stays molten simply because it lacks an easy way to cool. The Earth’s mantle and crust doesn’t provide very effective heat transfer from the core out to space so the outer/liquid core stays hot simply because the heat has nowhere to go.

As far as what would happen if it cooled, well it’s actually a question of when. The earth’s core is already cooling, and has been for billions of years. When the core finally cools fully, many things will happen, basically none of them good. The earth would lose its magnetic field and tectonic plates will stop moving are among the two biggest, both would essentially make the planet uninhabitable in the long run.

Fortunately we still have several billions years before this occurs.

The outer core is liquid iron and nickel (mostly). The inner core is solid and believed to be made of an iron-nickel alloy with some other elements (it’s never been directly measured).

It doesn’t “stay” molten, it simply takes a long time to cool down. We’re talking billions of years. This will likely never happen though, as our Sun will probably turn into a Red Giant and engulf everything up to Mars long before Earth’s core manages to cool.

If it did cool down however, we’d all be dead. The core is what creates Earth’s magnetic field, which protects us from things like cosmic radiation and solar winds.