Sequel of the preceding post Cosmogenesis (7) : The Date of the Creation
The Nebular Hypothesis
The ancient Babylonians had a different idea of how the world began. They believed that it had evolved rather than being created instantaneously. Assyrian inscriptions have been found which suggest that the cosmos evolved after the Great Flood and that the animal kingdom originated from earth and water. This idea was at least partially incorporated into a monotheist doctrine and found its way into the sacred texts of the Jews, neighbors and disciples of the Babylonians. It was also taken up by the early Ionian philosophers, including Anaximander and Anaximenes, and by the Stoics and atomists.
Democritus developed a theory that the world had originated from the void, a vast region in which atoms were swirling in a whirlpool or vortex. The heaviest matter was sucked into the center of the vortex and condensed to form the earth. The lightest matter was thrown to the outside where it revolved so rapidly that it eventually ignited to form the stars and planets. These celestial bodies, as well as the earth itself, were kept in position by centrifugal force. This concept admitted the possibility that the universe contained an infinite number of objects. It also anticipated the 19th century theory of the origin of the solar system, known as the nebular hypothesis, according to which a “primitive nebula” condensed to form the sun and planets.
The idea of universal evolution had a strong influence on classical thought and developed in various directions during Greek and Roman times. In the first century BC Lucretius extended the theories of atomism and evolution to cover every natural phenomenon[i] and argued that all living things originated from earth. Two centuries later, in his medical treatise On the Use of the Parts of the Body[ii], the Greek physician Galen (Claudius Galenus) expressed the essentially Stoic view that matter is eternal and that even God is subject to the laws of nature: contrary to the literal interpretation of the Genesis story, he could not have “formed man from the dust of the ground”; he could only have shaped the dust according to the laws governing the behaviour of matter. The Church Fathers, who insisted that the Creation was instantaneous, rejected any sort of evolutionary theory; to them the ideas of the Stoics and atomists were heretical.
In the second half of the 16th century the idea of universal evolution began to be incorporated into the new system of scientific thought resulting from the work of Copernicus, Kepler, Galileo, Descartes and Newton. According to Descartes, for example, space consisted of “whirlpools” of matter whose motion was governed by the laws of physics. Newton, with his theory of universal attraction, was accused of having substituted gravitation for providence, for having replaced God’s spiritual influence on the cosmos by a material mechanism[iii]. A new view of the world had nevertheless been established, whereby the workings of the universe were subject not to the whim of the Almighty but to the laws of physics – it was an irreversible step.
In the 18th century Newtonian theory came to dominate astronomical theory. The scriptures could no longer account for the origin of the world but Newton’s “uncreated” universe was no more satisfactory from a philosophical point of view. Moreover, since the earth no longer had a privileged position in relation to other celestial bodies (as it had in a geocentric universe), why should it have been created first? Science had established a new order of creation: first the stars, then the sun and finally the earth.
In the mid-18th century it began to be assumed that the early universe had been filled with some elementary fluid, a primeval substance from which the various celestial bodies had progressively emerged – an idea deriving largely from the Swedish mystic Emanuel Swedenborg. In his Prodromus Principiorum Rerum Naturalium (On the Principles of Natural Things), published in Germany in 1734, Swedenborg made the hypothesis that the planets, including the earth, had once been part of the sun and had separated themselves from it long ago; the solar system as a whole had originally been a nebula – like those we can now see in space – and the sun and the planets had only emerged as separate entities after a long period of evolution. It was therefore Swedenborg who first postulated what we now call the “nebular hypothesis”, although it is often attributed to Buffon.
In 1745, independently of Swedenborg, the French scientist had suggested ways in which celestial objects might have been formed and attempted to explain why all the planets orbited the sun in the same direction. According to Buffon the force that had created the solar system was the impact of a comet; this had thrown lumps of matter, which had been in the process of fusing with the sun, far enough from it not to be drawn back by its gravitational pull (this idea would be taken up again in the early 20th century by the English physicist James Jeans, but unsuccessfully). It is interesting to note that Buffon’s concept of opposing forces – centrifugal and gravitational – supports a myth which dates back to Heraclitus and parts of which are to be found in the Vedas: that of a great “pulsation”, a constant alternation in the balance between attraction and repulsion. Today’s astrophysicists reckon that these two forces coexist, in permanent opposition, in the solar system as well as in every galaxy.
The English scientist Thomas Wright published his major work, An Original Theory or New Hypothesis of the Universe, in 1750 and five years later completed his Universal Architecture (not published in his lifetime). His aim was nothing less than to reveal the Creator’s plan. Astronomy shows us what the universe looks like and determines our position within it but only religion, Wright argued, can give us a true picture of the Creation itself. He wanted to unify what we see through a telescope and what we know of the divine world of the Holy Trinity. The universe must therefore comprise a central region (the kingdom of God and the angels), a sphere surrounding that central kingdom (housing the sun and all the stars with their entourages of planets and living things) and a nebulous outer zone (the realm of the damned).
Despite its intention to reconcile science and religion, Wright’s work influenced rationalists like Herschel, Laplace and the German philosopher Immanuel Kant, whose Theory of the Heavens expressed a number of original ideas on cosmology. Kant applied the principles of Newtonian physics to the nebular hypothesis, giving it a consistency it had previously lacked. As far as the formation of the solar system (and of all other star systems) was concerned Kant had a grandiose vision of a primordial age when the infinite reaches of space were filled with matter, from which the planets and stars were formed. Dark and silent this veil of matter contained the seeds of the universe as we know it. Diderot’s Lettre sur les aveugles à l’usage de ceux qui voient (Note on the Blind for Those who See) of 1749 is a literary presentiment of this primeval state: “How many disfigured, misshapen worlds must have disintegrated and were perhaps being reformed and disintegrating again every second far away in space… where matter swirls and will continue to swirl in great masses until it has achieved a form in which it may survive.”
The French mathematician and astronomer, Pierre Simon, marquis de Laplace, defended the nebular hypothesis even more strongly than Kant, supporting it with mathematical reasoning as well as with reference to celestial mechanics. He proved that our solar system and other planetary and lunar systems were the result of nebulous masses acting in accordance with natural laws, as were the movements of those planets and moons and their relative sizes and distances from each other. Laplace derived his concept of a “primitive nebula” from the observations of astronomers such as Charles Messier and William Herschel, who had used the latest telescopes to catalogue hundreds of nebulous bodies. Some of these appeared to consist not of masses of stars but of clouds of opaque matter, which Laplace concluded must condense into stars. A man who constantly proclaimed, “I do not make hypotheses”, Laplace went on to make the most sensational hypothesis of the century: that the solar system had originated from a primitive nebulosity, a flat disc of slowly rotating matter, which had coalesced into lumps as it contracted and cooled. First its core had formed into a fireball (the infant sun) from which “wisps” of gas had escaped and quickly formed into rings surrounding the core; these rings, initially revolving in ellipses, then broke up into lumps, which condensed into young planets, emerging shining from their misty cocoon.
To believers in the Creation Laplace’s hypothesis was just another form of atheism, since it displaced God from His position as Creator of the stars, and opponents of the theory were delighted when telescopes revealed that some nebulosities were in fact clusters of stars: surely the same was true of all nebulae and it was only a matter of time before more powerful telescopes would prove the fact. The nebular hypothesis therefore remained unsubstantiated until the advent of spectroscopy, which allowed the light emitted by stars to be analyzed. In 1814 the German physicist Joseph von Fraunhofer discovered that the spectrum of a hot gas was broken up by dark lines (now known as Fraunhofer’s lines), caused by chemical elements in the gas. During the 1860s astronomers like Angelo Secchi in Italy and William Huggins in England undertook a systematic study of star spectra, thereby founding the discipline of astrochemistry. Like for the spectra of terrestrial objects, those of celestial objects reveal not only the presence of chemical elements, but also whether the object is solid or gaseous.
Many nebulae were thus proven to be enormous clouds of gas: no telescope, however powerful, would ever show them to consist of stars. Some of them even had a bright central point, indicating that a star was in the process of formation. The publication in the late 19th century of observations by the Irish astronomer William Parsons and by the Dane Heinrich Louis d’Arrest, accompanied by detailed drawings of nebulae, finally confirmed Laplace’s theory and established the nebular hypothesis as part of accepted cosmogony. It also proved to be a major contribution to physics, since it explained a number of the processes of star formation in terms of thermodynamics.
Scientists in various other fields of research dealt further blows to the traditional Creation myth: Darwin, of course, with his theory of evolution, but also archaeologists and philologists, who were studying ancient monuments and hieroglyphs. Historians such as Oppert, Rawlinson and Smith[iv] had succeeded in deciphering the inscriptions found in the great library of Assurbanipal (Sardanapalus) at Nineveh and an account of a deluge in the Epic of Gilgamesh appeared to be the source not only of the Babylonian myths but also of the story of the Great Flood in the bible. Genesis could therefore no longer be considered a reliable account of the Creation, as revealed to Moses by God Himself; it had become just one of many stories about the origin of the world, all of which had been influenced by various cultures and reflected the scientific knowledge of the people who had first conceived and recounted them.
[i] De Natura Rerum, book V.
[ii] De UsuPartium Corporis Humani, 11.14.
[iii] On this controversy see for example McCosh, The Religious Aspect of Evolution, New York, 1890, pp. 103-04.
[iv] George Smith, Chaldean Account of Genesis, New York, 1876, pp. 74-75.