The mantle is between 500-4500K, meaning most of it is hot enough to glow at least a dull red.
You don’t say lava is black because once it cools down it turns black…
I often forget we’re basically living on a spherical hot pocket fresh out of the microwave.
Crispy Crunchy Tender Flaky Crust, Earth pocket!
Here I thought the joke was going to be “The Earth is actually a complete sphere without having any slices or cross-sections taken out of it like that.”
Related fun fact: The Earth’s crust is largely made of feldspars: https://en.wikipedia.org/wiki/Feldspar
You mean it’s not a gobstopper?
Bastards! What am I doing licking things, then?
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Chocklet
One of the pictures shows the mantle having a slight green hue.
Kerbal space program was right!