The Legacy of Apollo
By HOMER E. NEWELL
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| Our conceptions are altered when the point of view is shifted. When the Apollo 15 astronauts took this picture from lunar orbit, they saw the Earth as a thin crescent. At the same time, we on Earth were seeing a nearly full Moon. |
Because we live on it, the Earth is the center of things for us. Around Earth all other celestial bodies circle endlessly, or so it seemed to our forebears. For countless generations men who thought about such matters regarded the Earth as the center of the universe. So satisfying was this view, so entrenched in doctrine and dogma did it become, that when Copernicus and Kepler challenged the idea, they stirred up a hornet's nest. The concept of the Sun as the central stillness in the solar system around which Earth and all other planets revolve was considered too unsettling to be tolerated, and edict and persecution sought to suppress these dangerous new ideas. But in vain, for the Copernican revolution in human thought continues to this very day. In countless ways it colors the picture men draw of themselves and of man's place in the universe.
Apollo's greatest impact was to impress dramatically upon men's minds, more clearly than ever before, the significance of the Copernican view. The spectacle of a spacecraft leaving Earth with the incredible speed of almost 6 miles per second- thirteen times faster than a rifle bullet- traveling through space like a miniature planet, bearing men for the first time to another world, focused the attention of hundreds of millions of people. We saw Earth as only one of nine planets in the solar system, insignificant, except to us, among the unreachable stars in the vast expanse of the heavens. In cosmic perspective Earth is but a tiny object in a remote corner of space, companion to a modest star, one of a hundred billion stars making up one of billions of galaxies scattered over unimaginable distances to beyond the farthest reaches to which we have been able to peer with the most powerful telescopes.
But while helping to convey Earth's insignificance in the cosmic scale, Apollo dramatically displayed Earth's uniqueness and overwhelming significance on the human scale. Standing in imagination on the rocky rubble of a lunar plain, looking through an astronaut's eye and camera out over the vast arid wasteland of our inhospitable satellite, we saw above the horizon the beautiful, blue, fragile Earth. It awakened a heightened appreciation of and sense of responsibility toward our home in space. In the entire solar system, 6 billion miles across, only Earth so far as we now know nourishes the vast abundance of life that we so casually accept. Only by understanding thoroughly our planet and our place on it can we hope to learn how to use its resources wisely, to preserve for future generations our island in space in its pristine vigor and beauty. And that is where the true significance of Apollo lunar science comes in.
To understand fully our own planet, it is essential that we study many planets, Photography and Spacecraft making comparisons among them. An inevitable myopia interferes when we try to learn about planets from the study of only one. The Moon is a planet in its own right, by reason of its substantial size and mass, and what we learn of lunar science also advances Earth science.
As our nearest neighbor in space, the Moon has long been an object of wonder and study. Through the telescope the astronomer has seen myriads of craters on its surface clear evidence of lava flows, and even some suggestion of current volcanic activity. The Moon is decidedly out of round. The sharpness of telescopic images, and the suddenness with which stars disappear behind the Moon and later reappear show clearly that the Moon has virtually no atmosphere. No mountain systems like the Rockies or the Himalayas could be seen. Without atmospheric erosion and mountain-building activity, we supposed that the Moon would preserve on its face the record of solar system history to the very earliest days. But viewing the Moon from 239,000 miles away left much room for speculation and disagreement. So when rockets became available, plans were quickly laid for investigating the Moon close at hand, eventually by man himself.
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