Today we honor and give thanks for a man who knew that everything worth striving for, every dream we pursue, every adventure that beckons, every challenge that calls forth our greatest efforts, cannot be accomplished alone. No one goes to the moon alone. No one accomplishes anything of lasting value in any realm of human endeavor alone.

In reading the many public tributes to Neil Armstrong, it’s obvious that we all assume that the defining moment of Armstrong’s life was walking on the moon, those amazing two and a half hours. How could it be otherwise? It was after all a first and giant step. Yet he tended to downplay the personal impact of the experience. Once when, speaking to a group of students, he was asked perhaps for the millionth time how walking on the moon changed his life, he replied that because of the moon he got to go to a lot more press conferences at which people ask how the moon changed his life. But he went on to say that when he was a kid the same age as the students asking questions, no one had ever flown a plane at supersonic speed. There was no space program. Going to the moon was pure science fiction. In the first half of his lifetime—everything changed.

Last week, Canon Vance Wilson—headmaster of St. Albans, a school of this Cathedral—addressed the students in their opening chapel, drawing their attention to the beautiful stained glass window known as the Space Window. “Gentlemen,” he said, “how about beginning this school year with a dream? Ever thought about being the first human being to walk on Mars? Why not? You wouldn’t be the first St. Albans graduate to do the impossible. You better get started soon, though. If you leave today, it’ll take you the entire school year.”

Without question, walking on the moon confirmed for Armstrong the importance of a dream, a compelling vision that propels us as individuals and a species where we have never been. And it pleased him whenever his example, in the words of his family, “inspired young people around the world to work hard to make their dreams come true, to be willing to explore and push the limits, and to selflessly serve a cause greater than themselves.”

But that cause, I suggest to you, for Neil Armstrong, was not exploration for exploration’s sake, but for the survival of the only planet we human beings call home. The defining moment for him, it seems to me, judging from the way he chose to live his life after Apollo 11, was when he looked out his spacecraft window. “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.” The earth was his rose, and it’s our rose, too.

Thus as we honor Neil Armstrong today with our words and prayers, I invite you all to imagine that peculiar sensation he would describe of watching the Earth become smaller and smaller; to see in your mind’s eye the thin strips of green around oceans of blue, and to remember that all the world’s populations live on those strips, with the small patches of brown quickly disappearing from your view. You can no longer see all that divides us as a species, only our common fate as those who call this beautifully spinning planet home.

You and I are responsible for our rose. In his child-like wonder and quiet determination, Neil Armstrong wanted us to know that. He urged us to work together, as we must, to solve the heart-breaking challenges and consider the breath-taking possibilities of our species.