What is it like being surface-heavy? First, it means you never need to fear heights. When you fall from a great height, two forces play tug-of-war: downward gravity and upward air resistance. Gravity works by pulling on your mass, so its strength depends on your interior. Air resistance works by pushing against your skin, so its strength depends on your surface. In short, your mass speeds up your fall, while your surface area slows it down. That’s why bricks plummet and paper flutters, why penguins can’t fly and eagles can. (Location 917)
