July 20

In 1969, around his birthday on July 20, the author had a conversation with his grandmother about the landing of two men on the moon. She doubted that it happened--and that it ever could happen. And she had good reasons. First, when we see it, the moon is always above the Earth. Anyone getting up to it could hardly stay on it for long: a person would fall off. Second, in any case, the moon was too small to hold one man, let alone two men and a vehicle. Furthermore, the moon changes shape. At one time, it is a full disk and, at another, a mere sliver. For a time, it disappears altogether. Since it changes size and shape, it must really be only an appearance of light, like a spot of light on a wall--not a solid body.

Grandmother proposed, with some assurance, that the astronauts must have gone to a mountain somewhere on Earth. She could imagine variations in the altitude of landscapes on Earth and could easily imagine a high point to which the astronauts had traveled. But confined as we are to this planet and lacking, through no fault of her own, the education that would have made her aware of the latest model of the solar system, she used her considerable intelligence to devise an explanation for the extraordinary claims she was hearing at the time.

The greatest leap we made in our conception of the moon is the realization that it is another world, a spherical body that occupies a point in space near Earth and is illuminated by the sun. The appearances of that body become intelligible in relation to this notion. Anyone can simulate the phases of the moon with a flashlight and a ball in a dark room.

In outer space, the notion of 'up and down' is not as useful as the ideas of 'in and out' or 'toward and away'. The ancients had some trouble imagining how anything could stay on the bottom or sides of a spherical body: put something anywhere but on the very top of a sphere and it will fall off, naturally. But that occurs to an object on a sphere within the gravitational field of Earth.

Our thought of north being 'up' and south being 'down' is purely conventional; it does not reflect a physical reality. People in the southern hemisphere do not fall off our planet despite the appearance of the northern hemisphere above the southern on a map. The reason why the people on Utsteinen Nunatak in Dronning Maud Land can remain as fixed to the Earth as the people traversing the Chersky Range is that they are all drawn inward toward the center of the globe.

Our progress as a species occurs with both conceptual and technological leaps. Understanding the moon as another world and sending humans there are two different accomplishments--distinct but related accomplishments.

Since July 20, 1969, there have been many missions into space but none as dramatic. What occurred that day was one of the greatest scientific and technological achievements in the history of the human race. The mission of Voyager 2--the 'Grand Tour' of our solar system--and the rover mission of Spirit and Opportunity on Mars, captured a vast amount of scientific data and much public interest as well. And they inspired awe in many observers--professionals and non-professionals alike. But they still pale in comparison to the landing of the first two men on the moon.

Growth and development of organisms--and nations--are not inevitable. What is inevitable is the fall from a height. Vitality requires a continual expenditure of energy. For living things and for nations, when efforts cease, decay begins. There is no law that ensures that America will continue to lead the exploration of outer space. In any event, no person, no nation will live forever. And yet we can avert an immediate decline.

Americans may take some comfort in recalling the landing of Apollo 11 on the moon. It was the first such landing. And if we decide to pass the torch to a new generation in another country, humanity can still advance in outer space. But our best and brightest may decide to work in China, Europe, India, Japan, Russia or whatever nation embarks on the next great mission beyond our planet.

Public interest, and even strong political pressures, may never be enough to motivate the funding of great explorations; inspired leadership is now what America needs the most.