FOR MOST of recorded history man's concept of the heavens, the universe, and his home world was much different than that developed in the past four hundred years, the past fifty years, or even in the past ten years. Astronomy as a science has a relatively short history, with the most rapid and exciting discoveries coming in the past few years, whereas astronomy as a source of amazement, fear, superstition, and awe has a long history.
Comets, eclipses, planetary conjunctions, and other natural astronomical phenomena were considered occasion ally as good omens by the ancients but usually as harbingers of pestilence and disaster. The heavens were closely tied to their mythology and theology. With the Renaissance in the sixteenth century, the present view of the universe began to take shape. Man began to realize the proper place of the earth in the universe. Today we take many of these painfully developed ideas for granted. In retrospect, it seems difficult to imagine how or why some of these early concepts were adopted and then held to so firmly in the face of contrary evidence.
However, it is sometimes also difficult to modify one's own concepts in view of the very rapid progress of astronomy. Only within this century did man come to realize the extreme size of the uni verse; understand the source of energy of the stars; develop realistic ideas on the changes within stars, within galaxies, and within the universe as a whole; first use radio, infrared, X-ray, and microwave techniques for astronomical observations; discover pulsars, quasars, and black holes; step on another astronomical body; and send an object of his design and construction out of our solar system.
These spectacular developments lead us to conclude that the universe is a dynamic, changing one, whereas medieval man viewed the universe as placid and static. Just as our concepts of the universe have changed, our ideas concerning God's management of it are changing.
Today the heavens appear much as David saw them when he wrote, "The heavens declare the glory of God; and the firmament sheweth his handywork" (Ps. 19:1). But now man has extended his senses by many thousandfold. We can observe more, understand more thoroughly the relationships of the uni verse, and better gain an insight into the character of the Creator than could David.
Earth-centered Model
To the casual observer the starry heavens appear quite peaceful, unchanging, and permanent. The stars seem to be situated on the surface of a large inverted bowl over a flat earth. During the course of one night they appear to rise in the east, pass across the sky and set in the west, following in like manner the motion of the sun during the day. So it appeared to ancient man. To him the stars were situated on a huge celestial sphere centered on this world. They rotated about him each day.
A slightly more careful observer, or one more patient to observe for a longer period, would detect some changes not apparent in a single night. Each evening the stars rise slightly earlier than the preceding night (about four minutes), so that in the course of a year they are back to their original positions relative to the sun. (A more astute observer might say the sun rises four minutes later each morning!) This means that the sun moves independently of the stars. Further evidence for this is indicated by the north-south motion of the sun relative to the stars during a year's time, causing our seasons.
Even more obvious are the constantly changing phases of the moon and its motion across the sky. The moon rises almost one hour later each day, so that in 29 days it has completed one circuit about the sky and exhibited a complete cycle of phase changes. Thus the moon must move independently of the sun and the stars.
Other changes can be noted by the unaided eye and must have been known to a shepherd such as David, accustomed to spending the nights outside. There are five "stars" that move! The ancients called them wanderers, or planets. These starlike-appearing objects undergo regular motions in the sky. These motions are complicated. At times their normal eastward motion halts, they move westward or retrograde for a time, then resume their eastward motion. It is difficult to understand this in terms of an earth-centered model. However, the motion of the planets is regular and predictable.
Heliocentric Model
Ever since the eighteenth century, man has realized that a heliocentric or sun-centered model for our solar system is both successful and simple. The earth is but one planet orbiting our sun in a regular way. The moon orbits the earth. The other five visual planets plus four telescopic ones, thousands of minor planets, and other assorted objects are all part of the sun's immediate family. The motions of the planets are highly predictable. Man-made instruments have passed through the immediate vicinity of four of them (not counting Earth) and will in a few years pass near the fifth. Probes have landed on one (Venus), and two space vehicles have landed on another (Mars). Man has visited the moon, walked on its surface, and returned samples to earth's laboratories.
Each of the planets has contained surprises for man: the magnetic field of Mercury; the retrograde rotation and high temperature of Venus; the seemingly water-carved channels, high volcanic craters, and immense chasms of Mars; the storms, satellites, structure, and radiation of Jupiter; the extremely low density and delicate ring structure of Saturn. What mysteries the other four hold one can only guess.
The planets are the close neighbors of Earth. It was a tremendous shift in perspective that allowed Renaissance man to conceive of the sun rather than the earth as the center of the universe. The earth suddenly became one of several planets, not the smallest, but not the largest either. It is unique, but so are each of the others. This shift was particularly important in that it allowed man to consider his home as a part of the universe, and not something so special, unique, and different that natural processes for the earth are different from the heavens. This shift in view allowed him to apply natural law as ob served in laboratories on earth to the planets, the stars, and the universe.
What About the Stars?
The solar system is undergoing regular changes as Earth and its companion planets move about the sun, each on its separate course. However, what about the stars?
Even the ancient Greeks noted some changes in the stars. Precession of the earth's rotation axis, which results in a systematic apparent shifting of all stars, was discovered by Hipparchus more than one hundred years before Christ. 1 However, of more significance is the observation that Algol, the demon star in the constellation of Perseus, undergoes a regular change in brightness. Here is direct evidence that the stars are not unchanging, although in this case the change is regular and periodic.
There are also rather random events such as meteors and comets, but these were thought in medieval times to be phenomena in the earth's atmosphere. Indeed, meteors are just that, caused when small objects from outer space collide with the thin upper atmosphere of Earth. Comets are interplanetary bodies and are part of our solar system.
One other type of change can easily be noted with naked-eye observation, although it is relatively rare. These are known as novae, a word meaning new. The Chinese began recording these "guest stars" several centuries before Christ. To the unaided eye a nova suddenly appears as a star where none was seen before. These "stars," however, slowly fade in the span of a few days or a few months, disappearing to the visual observer.
Even more spectacular are the supernovae. These occur much more rarely. The "new star" sometimes reaches such brilliance that it can be seen during the daytime. Four possible supernovae have been recorded in our galaxy during the past millennium: 1006 in the constellation Lupus, 1054 in Taurus, 1572 in Cassiopeia, and 1604 in Serpens.2 Before 1572 it was thought that these, like meteors and comets, were phenomena of the atmosphere of Earth, but Tycho Brahe demonstrated that the supernova that appeared that year had no observable parallax,3 and hence was extremely distant—out among the stars! Here is evidence that nonperiodic changes are occurring among the stars.
On the morning of July 5, A.D. 1054, Chinese astronomers observed a "guest star" in the constellation of Taurus.4 It became bright enough to be seen in the day. The star slowly faded over a period of two years until it disappeared. No record has been found of a European observation; however, a very interesting stone carving discovered in Navajo Can yon in northern Arizona, evidently drawn by Indians, depicts a large bright object just below a crescent-shaped one. 5 On that morning in 1054 the crescent moon was just two degrees above the position identified by the Chinese records.
It was not until the eighteenth century, when telescopes became available, that astronomers detected a turbulent gaseous nebula in the region of Taurus specified by the Chinese record. This is the Crab Nebula. Verification of the identification is provided by the observation that this nebula is expanding at about 680 miles per second. From its present diameter of about 6 light-years, it is quite easy to show that it must have begun its expansion sometime around the eleventh century. 6
Here is recorded a cosmic explosion of immense proportions. The Crab Nebula is a chaotic, complex cloud of gas. In time it will expand and diffuse. This is not a regular periodic change. Other events of this nature have been ob served and studied with the aid of the various instruments available to astronomers.
A supernova occurs about once per century per galaxy. What causes them? Models for the processes by which stars are sustained give an answer. These models predict that certain stars, as they exhaust most of their energy sup ply, become unstable and disintegrate in one tremendous flash. The majority of stars, according to these models, end their active life in a much more gentle manner. There is a rough agreement between predicted and observed rates of supernova occurrence.
At the center of the Crab Nebula is a pulsar, a very small star giving off regular pulses of light and radio energy. Pulsars are extremely dense stars that probably are a result of supernovae explosions. A number of pulsars have been discovered in our galaxy. Some of these are associated with large diffuse nebulae, indicating a long history of stellar activity and change. Evidently an exploding star is not an extremely rare object.
A Dynamic Changing Universe
Supernovae are not the only evidence that the astronomer has of irreversible changes among the stars. They are the most direct and spectacular. The entire pattern of stars, when graphed in a diagram of their brightness and temperature—the Hertzsprung-Russel diagram— can be interpreted in terms of a dynamic, changing universe in which stars are formed, use up their energy stores, and finally undergo collapse to some final cool cinder or else regurgitate their material back to the interstellar medium to form new stars. The evidence is not direct; the "lifetime" of a star is so long that astronomers cannot observe more than a small fraction of its "life." Only at certain times are the changes rapid enough to observe directly, yet there is excellent consistency in the entire picture.
To medieval man the heavens were peaceful, unchanging, and forever. The concepts that he ascribed to the sky reflect his concepts of God. The sun, planets, and the universe all revolved about their center, the earth. All the planets were perfectly spherical, without markings or any blemish. They moved in perfectly circular orbits. In short, the universe was dull, and consequently, God was dull.
In our present understanding the universe is dynamic and changing. Each planet is unique, different. The stars show many interesting variations. There are fireworks of exploding stars. Many astronomers believe that quasars may be exploding galaxies. There may be massive black holes trapping all matter, even light. Our Creator is not an uninteresting, dull Being. He is alive, vibrant, going about creation with a happy feeling, causing variety, introducing surprises and excitement. Yet underneath everything He is consistent and unchangeable in character.
How can the 200-inch telescope at Hale Observatory on Palomar Mountain in California show God's handiwork? Does the 1,000-foot radio dish at Arecibo, Puerto Rico, reveal the glory of God? What does the UHURA X-ray satellite tell of God's character? Is there a spiritual message in the faint radio transmissions of Pioneer 10 and 11? Is God found in the patterns of stellar characteristics, in exploding galaxies, in black holes?
Beyond the tarnishing effects of sin, astronomy reveals a universe that obeys the same physical laws that may be ob served here on earth; a universe that is complicated, interesting, and beautiful. It is not serene, static, and unchanging, but alive. We can observe billions of galaxies, each composed of several hundred billion stars similar to our own sun. It is a most magnificent testimony to God's creative ability and management.
Scientific study has hopefully dispelled man's fear and superstition of the heavens while increasing our awe and appreciation of our loving Creator. Astronomy shows that God is a Being who can conceive, create, and maintain a universe containing so much variety that even an eternity of study will always reveal something new and exciting to discover.
Notes:
1 Isaac Asimov, Asimov's Biographical Encyclopedia of Science and Technology (Garden City: Doubleday & Co. Inc., 1972), pp. 31-33.
2 Paul Gorenstein and Wallace Tucker, "Supernova Remnants," Scientific American, July, 1971.
3 George O. Abell, Exploration of the Universe, third edition (San Francisco: Holt, Rinehart and Winston, 1975), pp. 41, 42.
4 Jan H. Oort, "The Crab Nebula," Scientific American, March, 1957.
5 Ibid.
6 Ibid.
