By now most of us recognize the Blue Marble photograph. Even if we don’t know it’s called the Blue Marble photograph, we’ve seen this picture.

It was a meta moment for our planet, as the Apollo 17 astronauts looked out their window and snapped a shot of our globe floating like a blue-and-white dream in a sea of darkness. The first time Earth was viewed from space.

What I didn’t know, but only learned by reviewing a new book, is that the raw image originally submitted to NASA placed the southern hemisphere at the top of the frame. (Those weightless astronauts didn’t know which way was up!) NASA flipped the image before releasing it to the public. It would have been mind-bending otherwise.

To learn why North landed on top, you’ll need to read the book. But isn’t it interesting to ponder a world where what’s up is down and what’s down is up? Kind of puts us in our place, doesn’t it?