For those who remember being glued to the TV on July 20, 1969, when Armstrong and Edwin “Buzz” Aldrin walked on the moon, and for a beleaguered space agency hoping to recapture lunar glory, Monday’s 40th anniversary of the first landing is a powerful historical beacon.The moon landing was “nothing less than a turning point in human evolution,” Chaikin said. “We didn’t go to the moon for the sake of experimentation; we went because we wanted to beat the Russians. But what we got as a bonus was a whole new perspective on ourselves.We have all seen the pictures, but in those distant Apollo years, 24 travelers saw the real thing: The whole Earth, hanging in space, visibly alive in a deserted cosmos. Almost without thinking about it, this band of test pilots achieved the dream of the philosophers of old: to behold the entire world.