Forty-eight years ago Neil Armstrong spoke the words “That’s one small step for a man, one giant leap for mankind.” Buzz Aldrin, his partner on the moon mission, radioed Nasa before stepping out of the space module. “I would like to request a few moments of silence,” Aldrin said, “and to invite each person listening in, wherever and whomever they may be, to pause for a moment and contemplate the events of the past few hours, and to give thanks in his or her own way.”