It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn’t feel like a giant. I felt very, very small.
Those are the words of Neil Armstrong [1930–2012] reflecting on the awareness-altering, mind-boggling experience of observing the Earth from outer space. The effect that many astronauts experience after viewing such breathtaking sight is called the overview effect: “[It] is a cognitive shift in awareness reported by some astronauts and cosmonauts during spaceflight, often while viewing the Earth from orbit or from the lunar surface.” It has been described as “a complete engulfment by a profound sense of universal connectedness”.
I imagine this would be the ultimate high.