One youtube video[1] I watched had someone state that if you scaled up one of the curved mirrors to the size of the Earth, the largest imperfection would be the

One youtube video[1] I watched had someone state that if you scaled up one of the curved mirrors to the size of the Earth, the largest imperfection would be the width of a hair. [1] https://www.youtube.com/watch?v=en7hhFJBrAI https://www.youtube.com/watch?v=en7hhFJBrAI around 7:30