From Hubble you can see the whole thing. You can see the curvature of the Earth. You can see this gigantic, bright blue marble set against the blackness of space, and it’s the most magnificent and incredible thing you’ve ever seen in your life. One thing I was not prepared for was how blue it is, how much water there is. Rick Mastracchio, a veteran spacewalker, once described it to me by saying, “You’re always over the Pacific.”
