Now, suppose I walk a mile away and I hold this ball up. Now, this ball you probably won't see really. Well, you might see it if you have really good vision. But I don't think I'll see it a mile away. Now, suppose I hold this really tiny marble, the solid sphere, from a mile away you definitely won't see this one. So in other words, the smaller you go, the less you see its position and the less you see its velocity.