Mountains could be what happens when Father Earth eats something that doesn’t agree with him. When he burps, mountains pop up.""That’s absurd," Keselo said, trying not to laugh."If you’ve got a better theory, I’d be happy to hear it," Red-Beard said mildly. "Anyway, a burp isn’t anything but air that boils up out of a man’s stomach, so Father Earth’s mountains have chunks of empty air in the middle of them—burps that didn’t quite manage to make it to the surface, you understand.