I read that the temperature in the ground goes up about 30 degrees Celsius each km^-1 farther down you get. And it gets hotter than he11 after a ways.
Here's what I can't figure out. Let's say it's summer time and the temps stay up around 100F up here on the top. But when you go down like 10' the soil temp is like 55F.
How's that happen when it's hotter than 55 F both below and above that depth?