Enveloping darkness all around, the marble before you is a planet called Earth. Its image at this vantage point is that of a beautiful marble, ever changing in appearance and horrifyingly fragile. And just as if it really were a marble, you want to reach out and save it before it is consumed by total blackness.
This picture was taken in 1968 by the Apollo 8 crew. Can you imagine being there? Seeing your home grow smaller in apparent size; realizing that most everything you know, all of your experiences, everything, is more-or-less confined to a single pin prick on that dot. I can imagine it being a very humbling and stomach-churning experience as the true circumstance of our being is finally digested.