Vision in a tree of forests

......With our feet on the ground and our heads only slightly higher in the air its difficult to tell and easier to forget the Earth is round. About the only thing we seem to know for certain is that it’s permanent, hard and daily and sometimes, these days, perhaps a little fragile. But go a hundred km up and our relationship with it begins to look different. From orbital space the globe becomes a true sphere; from the Moon it’s a blue planet in the night sky; from Mars it’s gone into the stars. And from most anywhere beyond that, only its cosmic environment exists. That’s the whole story behind gaining perspective....