For the bulk of human history, it’s been impossible to put Earth in cosmic perspective.
Bound by gravity and biology, we can’t easily step outside it, above it, or away from it. For most of us, Earth is inescapably larger than life. Even now, after nearly six decades of human spaceflight, precious few people have rocketed into orbit and seen the sun peeking out from behind that curved horizon. Since 1961, a mere 556 people have had this rarefied experience. Fewer, just 24, have watched Earth shrink in the distance, growing smaller and smaller until it was no larger than the face of a wristwatch. And only six have been completely alone behind the far side of the moon, cut off from a view of our planet as they sailed in an endlessly deep, star-studded sea.
It’s an inherently unnatural thing, spaceflight. After all, our physiology evolved specifically to succeed on this planet, not above it. Perhaps that’s why it can be difficult for astronauts to describe the experience of seeing Earth from space.