We're told oxygen is the most common element in the Earth's solid crust. But how much oxygen is there? Let's compare to the amount of oxygen in the Earth's atmosphere, like this: The most common minerals in the Earth's crust are feldspars, and sanidine is a typical feldspar. Let's assume the entire crust is made of sanidine, with a density of . The radius of the Earth is and let's say the crust is the upper of it. Let's model the Earth's atmosphere as a layer on top of the Earth about thick with an average density of , and which is oxygen by mass. Use this information to calculate the ratio of the mass of oxygen in the Earth's atmosphere to the mass of oxygen in the Earth's crust. Round your answer to significant digits.