The Curvature of the Universe

We don't really care about how much the sun is bending the shape of space in our neighborhood. That doesn't affect the overall shape of the universe. What we want is the curvature on the biggest scale. And you can put stuff in the universe, and that can change the amount of curvature. You can make the universe more or less curved by putting stuff into it. But you can’t change the fundamental nature of the curvature or topology of the world.