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.
