Earth explained - with a boiled egg | BBC Ideas #bbcideas #science

You might not realize it, but our planet is a bit like a soft-boiled egg. What? Let me show you. Earth is essentially made up three main layers: the core, the yolk, the mantle, the white part, and [music] the crust, the eggshell. Together, these layers are known as the geosphere. When Earth formed 4 and 1/2 billion years ago, it was this chaotic molten mess of elements where the heaviest, such as [music] iron, sank towards the center to form the core, and the lighter ones rose towards the surface. Now, just like this yolk here, the core exists in both solid and liquid states. But unlike an egg, its temperatures can reach an incredible 4,500° C, which is even hot enough to melt diamonds. So, what causes all this heat? Well, some of it comes from elements releasing heat energy as they decay, >> [music] >> alongside leftover heat from Earth's early formation. So, it's this internal heat that's driving the whole of the geosphere. Ever so slowly, and we're talking hundreds of millions of years slow, the outer layers of early Earth cooled and solidified into the mantle and then the crust. Technically, the mantle is solid, but under extreme heat and pressure, it does actually flow and move a bit like this egg white. As heat continued to rise through the mantle, it created these slow circulatory movements, which cracked Earth's outer shell into large slabs of rock called tectonic plates. So, here we are living on the edge of a roiling mass of deadly material just casually eating a boiled egg for breakfast.