This is one of my greatest hits from a almost exactly three years ago. I'm reposting it now and then I'll have something to say about it before I get back to Cost Effectiveness Analysis. - C
In ancient times, people looked up at the sky and it appeared that the sun, moon and stars were revolving about them. The ancient Greeks studied the heavens more closely and noticed that, along with the sun and moon which wandered among the apparently fixed stars, there were a few stars that also wandered. Based on the geocentric assumption, Ptolemy devised a mechanical model of the universe in which the heavenly bodies were embedded in crystal spheres, rotating about the center of the earth. (By the way, the Greeks were well aware that the earth was spherical, and even produced a very accurate estimate of its diameter.) Obviously, something must keep the heavenly bodies from falling to the earth as everything does, but that something must be invisible, so crystalline spheres seemed to do the trick.
Over the ensuing centuries, closer observations of the planets challenged Ptolemy's model. They would acclerate and decelerate, even briefly reverse direction. The solution was to make the centers of their spheres themselves rotate about other centers, rather than being fixed. Even these solutions failed upon more exact measurements, and so the epicycles needed epi-epi-cycles of their own.
In 1514 the Polish mathematician Nicolas Copernicus gave a handwritten book to a few of his friends. In it he declared seven of what he called "axioms," though they are in fact deductions:
- There is no one centre in the universe.
- The Earth's centre is not the centre of the universe.<./li>
- The centre of the universe [i.e., solar system] is near the sun.
- The distance from the Earth to the sun is imperceptible compared with the distance to the stars.
- The rotation of the Earth accounts for the apparent daily rotation of the stars.
- The apparent annual cycle of movements of the sun is caused by the Earth revolving round it.
- The apparent retrograde motion of the planets is caused by the motion of the Earth from which one observes.
In 1543, shortly before his death, he published the full elucidation of his theory under the title "On the Revolutions of the Heavenly Bodies." He had deduced a much simpler explanation of astronomical observations than Ptolemy's.
Galileo then used a new invention, the telescope, to make observations which conclusively proved the theories of Copernicus. For example, he observed the phases of Venus, which demonstrated that it revolves around the sun. He also discovered moons of Jupiter, which would have smashed its crystalline sphere, although neither he nor Copernicus had any way of explaining what else held the heavenly bodies aloft.
As we know, the Pope and his lieutenants refused to look through the telescope. They threatened to torture Galileo to death, in the name of Christ, if he continued to defend the Copernican system, and he relented. But the truth could not be denied. Kepler improved on Copernicus by determining that orbits were not circles, but ellipses. Newton developed a mathematical theory of gravitation which, among other achievements, finally demolished the conception of any "center" of the universe (a conclusion which Copernicus had somehow intuited, but not pursued). By the late 19th Century, improved telescopes and observational and analytic methods had made it possible to prove that the stars are trillions of kilometers from the earth, and are objects similar to the sun. By the 1920s, astronomers had determined that the stars occupy a volume a few hundred thousand light years across, the Milky Way galaxy, which they believed constituted the entire cosmos.
Then Edwin Hubble discovered that most of the objects known as nebulae are not, in fact, clouds of gas, but other galaxies beyond our own, millions of light years away. Then he discovered that distant galaxies are moving away from our own at substantial fractions of the speed of light -- that the universe is expanding. From this astonishing revelation, scientists were able to begin to deduce the history of the universe, and to speculate on its ultimate fate.
Our universe -- everything we can observe, that is, although quite possibly not everything that is or has been or may be -- is about 13 1/2 billion years old. The earth came along much later, about 4 1/2 billion years ago. The universe is so vast that there is no referent to human experience in the distance to even the closest star, while that distance is but a hundred thousandth of the width of the galaxy. The nearest galaxy (other than two small satellites of the Milky Way), Andromeda, is almost 3 million light years away.
Here is a portion of an image called the Hubble Deep Field, looking out in space and back in time nearly 12 billion years. This is a tiny piece of the sky, smaller than the end of a pencil held at arms length:
Each of the galaxies in the image -- and the tiny red dots are very distant galaxies -- contains on the order of 200 billion stars (as does our own).
These discoveries have smashed completely, and forever, the biblical cosmos. If there is a sentient creator of the universe, the purpose of the creation cannot have had anything to do with us. The universe is indifferent to our existence. A million galaxies like our own could vanish in an instant, and the universe would go on, not recognizably changed. This is the cosmos that we have discovered with our senses, and our reason, and our wondrous tools. But it is very difficult for most people to accept, and most people do not accept it. Two hundred thousand years of cultural development, of attitudes about the world, of explanation, of belief; the bedrock of the social order in religious authority, the answer to the terror of death and the futility of bereavement, the anchor of purpose; all swept away in a few hundred years, in a devastating avalanche of nearly incomprehensible truth.
It is no wonder that we are experiencing a turning away from reason, and truth, a flight into comforting darkness. Perhaps we have elevated such a limited, willfully ignorant man [i.e., George W. Bush] to our highest office precisely because his limitations are comforting. But the dark ages must be over now. If we are going to survive the challenges ahead of us, we must step out into the light, no matter how painful, and never turn back.
There is still a source of hope, of meaning, and purpose, and social order. That is, or course, humanity -- our astonishing selves. We are on our own, but that does not mean that we cannot find our own meanings, our own purposes, and succeed.