Kant, Universal Natural History and Theory of HeavenImmanuel Kant Universal Natural History and Theory of Heaven Translated by Ian C. Johnston Malaspina University-College Nanaimo, BC Copyright Information Contents of the Entire Work Dedication Preface PART ONE Short outline of the necessary fundamental principles of Newtonian philosophy required for an understanding of the following theory Outline of a general systematic arrangement for the fixed stars, derived from the phenomenon of the Milky Way. Similarity of this system of fixed stars with the planetary system. Discovery of many such systems, showing up in the expanse of heaven in the form of elliptical shapes. New idea about the systematic arrangement of all creation. Conclusion. Probable assumption about more planets beyond Saturn, deduced from the law according to which planetary eccentricity increases with distance. PART TWO Section One Grounds for the theory of a mechanical origin for the world. Counterarguments. The only possible idea which satisfies both. First condition of Nature. Scattering of the all material elements throughout the entire extent of space. First movement because of the power of attraction. Start of the development of a body at the point of the strongest attraction. General sinking down of elements towards this central body. Power of repulsion of the smallest particles in which the material stuff is diffused. Altered direction of the downward movement through the combination of this force with the first one. Uniform movement of all these motions in the same direction. Impulse of all particles to bring themselves to a common plane and to accumulate there. Slowing down of the velocity of their movement to an equilibrium with the gravity at the distance from the sun at that location. Free movement of all particles around the central body in circular orbits. Development of the planets from these moving elements. Free movement of the planets put together from these elements in the same direction on a common plane, with almost circular orbits for planets near the central point and with increasing degrees of eccentricity for planets further away from this central point. Section Two Deals with the different densities of the planets and the relationship of their masses. Reason why the closer planets are of a denser type than the distant ones. Inadequacy of Newton's explanation. Why the central body is of a lighter sort than the closest spheres moving around it. Relationship of the planetary masses according to the ratio of their distances. Reason for their manner of development: why the central body has the largest mass. Calculation of the spread out solution in which all the elements of the cosmic matter were scattered. Probability and necessity of this thin distribution. Important proof for the manner of the development of the heavenly bodies derived from a remarkable analogy by Buffon. Section Three Concerning the eccentricity of the planetary orbits and the origin of comets. The eccentricity increases in stages with the distances from the sun. Cause of this law derived from cosmogony. Why the comets' orbits freely deviate from the plane of the ecliptic. Proof that the comets are made out of the lightest sort of material. Parenthetic observation on the northern lights. Section Four Concerning the origin of the moons and the movements of the planets around their axes. The material for the development of the moons was contained in the sphere out of which the planet assembled the parts for its development. Cause of the movement of these moons with all their rules. Why only the larger planets have moons. Concerning the axial rotation of the planets. Whether the moon previously had a faster rotation. Whether the velocity of the earth's axial rotation is decreasing. Concerning the position of the planetary axes in relation to the plane of their orbits. Displacement of their axes. Section Five Concerning the origin of Saturn's ring and the calculation of the planet's daily rotation from the relationship with this ring. First condition of Saturn compared to the composition of a comet. Development of a ring from the particles of its atmosphere by means of an impressed movement from the impulse of its rotation. Computation of the time of Saturn's axial rotation according to this hypothesis. Observation on the shape of Saturn. Concerning the general flattening of the spheres of cosmic bodies. A closer determination of the composition of this ring. Probable assumption of new discoveries. Whether the earth had a ring before the Flood. Section Six Concerning the light of the zodiac. Section Seven Concerning creation in its entire infinite extent, both in space and time. Origin of a large system of fixed stars. Central body in the mid-point of the system of stars. Infinity of creation. General systematic relationship in its entirety. The central body of all of Nature. Successive continuation of creation into infinite time and space through the ceaseless development of new worlds. Observation on chaos in undeveloped Nature. Gradual decay and destruction of the cosmic structure. Appropriateness of such a concept. Renewal of fallen Nature. Supplement to Section Seven Universal theory and history of the sun in general. Why the central body of a cosmic structure is a fiery body. Closer observation of its nature. Thoughts on the alterations in the air surrounding the sun. Extinguishing of suns. Closer glance at its shape. Wright's opinion concerning the mid-point of all of Nature. An improvement on this opinion. Section Eight General proof of the correctness of a mechanical theory for the general arrangement of the cosmic structure, and particularly for the certainty of the present theory. The inherent capability in the nature of things to raise themselves on their own to order and perfection is the most beautiful proof of the existence of God. Defense against the charge of naturalism. The arrangement of the cosmic structure is simple and not set beyond the forces of Nature. Analogies which certainly confirm the mechanistic origin of the world. The same point proved from exceptions. The introduction of an unmediated order created by God does not deal satisfactorily with these questions. Difficulty which made Newton give up the mechanical theory. Solution to this difficulty. The proposed system is the only possible way to deal satisfactorily with the basic principles of both sides. Further proof from the relationship of the density of planets, their masses, the space in between their locations and the gradual interrelationships of their measurements. The motivating principles of God's choice do not immediately determine these conditions. Justification with respect to religion. Difficulties which present themselves with the theory of the unmediated order created by God. PART THREE Contains a comparison between the inhabitants of the stars. Whether the planets are inhabited. Reasons to doubt this. Basis of the physical relationships between the inhabitants of the different planets. Observation on human beings. Causes of the imperfections in human nature. Natural relationship of the physical characteristics of living creatures according to their different distances from the sun. Consequences of this relationship for their spiritual capacities. Comparison of thinking beings on different celestial bodies. Confirmation from certain circumstances in their dwelling places. Further proof from the disposition of God's providence, which is created in their best interests. Short digression. Conclusion The conditions of human beings in the future life. Universal Natural History and Theory of Heaven To the most serene, the mightiest king and master Frederick King of Prussia Margrave of Brandenburg Lord Chamberlain and Elector of the Holy Roman Empire Sovereign and Highest Lord of Silesia, etc. etc. My all honored King and Master, Most serene and mighty king, All honored King and Master, The feeling of my lack of worth and the radiance from the throne cannot make me so foolish and timid, when the honour which the most gracious monarch dispenses with equal magnanimity among all his subjects gives me grounds for hope that the boldness which I undertake will be looked upon graciously. In most submissive respect I lay at the feet of your eternal kingly majesty one of the most trifling samples of that eager spirit with which your highness's schools, through the encouragement and the protection of their illustrious sovereign, strive to emulate other nations in the sciences. How fortunate I would be if the present endeavor succeeded in making the efforts with which the humblest and most respectful subject constantly tries to make himself in some way of service to the Fatherland win the highest possible feeling of goodwill of his king. With the utmost devotion until my dying day, Your eternal majesty's most humble servant The author Königsberg 14 March, 1755 [Back to Table of Contents] Preface I have selected a subject which, in view both of its inherent difficulty and also of religion, can right from the start elicit from many readers an unfavorable judgment. To discover the systematic arrangement linking large parts of creation in its entire infinite extent and to bring out by means of mechanical principles the development of the cosmic bodies themselves and the cause of their movements from the first state of nature, such insights seem to overstep by a long way the powers of human reason. From another perspective, religion threatens with a fiery accusation about the presumption that one is allowed to be so venturesome as to attribute to nature in and of itself such consequences in which we rightly become aware of the immediate hand of the Highest Being and worries about meeting in the inquiry into such views a defense of the atheist. I really perceive all these difficulties, and yet I am not fainthearted. I feel all the power of the obstacles ranged against me, and I am not despondent. On the basis of a slight assumption I have undertaken a dangerous journey, and I already see the promontories of new lands. Those people who have the resolution to set forth on this undertaking will enter these lands and have the pleasure of designating them with their very own names. I made no commitment to this endeavor until I considered myself secure from the point of view of religious duty. My enthusiasm has doubled as I witnessed at every step the dispersal of the clouds which behind their obscurity seemed to hide monsters and which, after they scattered, revealed the majesty of the Highest Being with the most vital radiance. Now that I know that these efforts are free of all contention, I will faithfully introduce what well-meaning or weak-minded people can find shocking in my proposal and am cheerfully ready to submit it to the strict inspection of a council of true believers, which is the mark of an honest mind. Let the spiritual counselor first, therefore, hear the basis for what I have to present. If the planetary structure, with all its order and beauty, is only an effect of the laws of motion in matter left to itself, if the blind mechanism of natural forces knows how to develop itself out of chaos in such a masterful way and to reach such perfection on its own, then the proof of the primordial Divine Author, which we derive from a glance at the beauty of the cosmic structure, is wholly discredited. Nature is self-sufficient, the divine rule is unnecessary, Epicurus lives once again in the midst of Christendom, and an unholy philosophy steps on the faith which emits a bright light to illuminate it. If I found this criticism valid, then the conviction which I have of the infallibility of divine truths is for me so empowering, that I would consider everything which contradicts it sufficiently refuted by that fact and would reject it. But the very agreement which I encounter between my system and religion raises my confidence in the face of all difficulties to an unshakable composure. I recognize all the value of those proofs which people derive from the beauty and perfect organization of the cosmic structure to confirm the primordial and most eminently wise Creator. If we do not obstinately deny all conviction, then we must agree with such incontrovertible reasons. But I maintain that the people who defend religion in this way, by presenting an unnecessarily weak case, make use of such principles badly, so as to perpetuate the conflict with the natural scientists. People are accustomed to take note of and to extol the harmony, beauty, the purposes, and a perfect interplay of means and ends in nature. But while they, on the one hand, extol nature, on the other hand, they seek to diminish it again. This fine consistency, they say, is foreign to nature. Left alone to its universal laws it would bring forth nothing but disorder. The harmonies demonstrate a foreign hand, which knew how to force material left without any regularity into a wise design. But I answer that if the universal material laws were established equally as a result of the highest design, then they could presumably have no purposes except to act on their own to fulfill the plan which the Highest Wisdom has set out for itself. But if this is not the case, should we not be drawn to experiment with the belief that at least matter and its general laws may be independent and that most eminently wise power, which knew how to make use of them so splendidly, may indeed be great, but not infinite, certainly powerful, but not totally self-sufficient? The defender of religion fears that this same harmony which can be explained by the natural tendency of matter must demonstrate the independence of nature from divine providence. He clearly confesses that if people can discover natural reasons for all the order in the cosmic structure, something which can bring it into existence from the most universal and essential characteristics of matter, then it may be unnecessary to invoke the highest ruling power. According to the natural scientist's calculations, he finds nothing to quarrel with in this claim. He hunts after examples which establish the fertility of general natural laws for perfectly beautiful consequences, and brings true believers into danger through such proofs, which in their hands could become invincible weapons. I will cite an example. People have already often proposed as one of the clearest proofs of a kind of providence solicitous of human welfare that in the hottest parts of the earth the sea winds, right at the very time when the heated land most requires cooling, spread over the land and refresh it, as if they were summoned. For example, in the island of Jamaica, as soon as the sun has climbed sufficiently high to heat the land most strongly, just after 9 in the morning, a wind begins to come in from the sea and blows from all sides over the land. Its strength increases proportionally with the elevation of the sun. Around 1 in the afternoon, when it naturally is the hottest, the wind is at its strongest. It gradually decreases with the declination of the sun, so that in the evening the very same stillness reigns as at the start. Without this welcome arrangement, the island would be uninhabitable. All coastal lands lying in the hot places on the Earth enjoy this same benefit. Moreover, it is most essential for them, because they are the lowest places on dry land and also suffer the greatest heat. For the higher regions in the country, which this sea wind does not reach, are in less need of it, because their higher location places them in a region of cooler air. Is not all this beautiful? Are there not clear purposes which have been realized by judiciously applied means? However, by way of a counterargument the natural scientist must find the natural causes of this in the general characteristics of air, without needing to assume any special arrangements in the matter. He observes correctly that these sea winds have to go through such periodic movements, even if no human beings lived on the island, for no reason other than the property of the air (which is indispensably necessary only for the growth of plant life), without any goal directed intention of helping inhabitants, namely, because of its elasticity and weight. The sun's heat upsets the air's equilibrium by thinning out the air over the land thus allowing the cooler sea air to rise from its position and take the place of the air over the land. What uses generally advantageous to our planet Earth do the winds not possess? What uses does the keen intelligence of human beings not make of them? However, no other arrangements were necessary to create them except the general conditions of air and heat, which also must occur on the Earth without reference to these purposes. At this point the freethinker says if you concede the point that when people infer useful and purposeful arrangements from the most general and simplest natural laws, then we have no need of the special rule of a Highest Wisdom, then consider proofs which will entrap you by your own admission. All nature, especially in the wild, is full of such proofs, which permit us to recognize that matter, which organizes itself through the mechanical operation of its own forces, has a certain regularity in its effects and without compulsion satisfactorily acts by appropriate rules. When, in order to come to the rescue of the worthy cause of religion, a well-meaning person wishes to contest this capacity of general natural laws, then he will embarrass himself and by a poor defense give atheism a chance to triumph. However, let us see how these reasons, which we fear in the hands of our opponents as injurious, are by contrast strong weapons to use in the fight against them. Matter, which organizes itself according to its general laws, produces through its natural processes or, if we prefer, through a blind mechanical process, good consequences, which appear to be the design of a supremely High Wisdom. When left to themselves, air, water, and heat produce wind and clouds, rain, and streams, which irrigate lands, and all the useful consequences without which Nature would have to remain sad, empty, and barren. However, they produce these results not through mere chance or accident (which could have just as readily resulted in disaster). But we see that these consequences are limited by natural laws so as to work only in this way. What should we then think of this harmony? How would it really be possible that things with different natures should strive to work in cooperation with one another for such perfect coordination and beauty, even with purposes in such matters which are to a certain extent beyond the range of lifeless material stuff, namely, the benefit of human beings and animals, unless they recognized a common origin, namely, an Infinite Understanding, in which the essential interrelated construction of everything was planned? If their natures were necessarily isolated and independent, what an astonishing contingency that would be, or rather, how impossible it would be that with their natural efforts they should mesh so exactly together, as if an overriding wise selection had united them. Now, I confidently apply this concept to my present enterprise. I summon up all the material stuff of all worlds in a universal confusion and create out of this a perfect chaos. According to the established laws of attraction, I see matter developing, and it modifies its motion through repulsion. Without the assistance of arbitrary fictions, I enjoy the pleasure of seeing a well-ordered totality emerge under the influence of the established laws of motion, something which looks so similar to the same planetary system which we see in front of us, that I cannot prevent myself from believing that it is the same. This unanticipated revelation of the order of nature on a grand scale I find at first suspicious, because it establishes a well-coordinated and correct system on such a meagre and simple foundation. Finally, on the basis of the previously outlined observation, I advise myself that such a natural development is not something unheard of but that nature's essential striving necessary brings such things with it and that this is the most marvelous evidence of her dependence on that Primordial Essence which has within Itself the origins of being, together with the first laws by which nature operates. This insight doubles my trust in the proposal I have made. The confidence increases with each step I take as I continue on, and my timidity disappears completely. But the defense of your system, it will be said, is at the same time a defense of the opinions of Epicurus, to which it has the closest similarity. I will not altogether deny the truth of this remark. Many people have become atheists through the apparent truth of such reasons which, with a more scrupulous consideration, could have convinced them as forcibly as possible of the certain existence of the Highest Being. The consequences which a perverse understanding infers from innocent basic principles are often very blameworthy. Although his theory was what one would expect from the keen intelligence of great spirit, Epicurus's conclusions were of this kind. I will also not deny that the theory of Lucretius or of his predecessors (Epicurus, Leucippus, and Democritus) has much similarity to mine. Like those philosophers, I set out the first condition of Nature as that state of the world consisting of a universal scattering of the primordial material of all planetary bodies, or atoms, as they were called by these writers. Epicurus proposes a principle of heaviness which drives these small elementary particles downwards, and this appears not very different from Newton's power of attraction, which I assume. He also assigned to these particles a certain deviation from the straight linear movement of their descent, although at the same time he had an absurd picture of the cause and consequences of this deviation. This deviation comes about to some extent from the alteration in the linear descent, a change which we derive from the force of repulsion of the particles. Finally, came the eddies, which arise from the confused movement of the atoms, a major part of the theories of Leucippus and Democritus. We will meet them also in our theory. But such a close affinity with a theory which was truly the theory of atheism in ancient times does not lead mine to be grouped with their errors. With the most foolish opinions which can win popular applause, sometimes there is some truth to remark upon. A false basic assumption or a pair of unexamined coordinating principles lead people from the footpath of truth through unnoticed misdirections right to the abyss. Nonetheless, there remains, in spite of the above mentioned similarity, an essential difference between the ancient cosmogony and the present one, so that one can derive from the latter totally opposite consequences. The previously mentioned teachers of the mechanistic development of the cosmic structure derived all order which they could perceive in it from chance accident which allowed the atoms to come together in such a fortunate way that they created a well-ordered totality. Epicurus was even so unconscionable that he demanded that the atoms swerved from their direct linear movement without any cause, so that they could run into each other. Collectively these writers pushed this absurdity so far, that they even attributed the origin of all living creatures to this blind collision and, in effect, derived reason from irrationality. In my theory, by contrast, I find matter bound by certain necessary laws. I see a beautiful and orderly totality developing quite naturally out of its total dissolution and scattering. This does not happen by accident or chance. We see that natural characteristics necessarily bring this condition with them. Hence, will we not be moved to inquire why matter must have just such laws which forcefully bring order and prosperity? Was it really possible that many things, each of which has a nature independent of the others, should on their own constitute themselves in such a way that a well ordered totality arises? And if they do this, is there not an undeniable proof of the commonality of their primordial origin, which must be a self-sufficient Highest Reason, in which the natures of things were designed for common purposes? The material which is the primordial stuff for all things is thus bound by certain laws. Freely left subject to these laws, it must necessarily bring forth beautiful combinations. It has no freedom to deviate from this planned perfection. Since it also finds itself subject to the loftiest wise purpose, it must of necessity be set in such a harmonious relations through a First Cause which rules it. There is a God for just this reason, that Nature, even in a chaotic state can develop only in an orderly and rule-governed manner. I have such a high opinion of the honest minds of those people who confer upon this proposal the honour of testing it, that I remain confident that, where the basic principles mentioned above will still not be able to get rid of all worries about the deleterious consequences of my system, nevertheless at least they place the sincerity of my intentions beyond doubt. If, in spite of this, there are malicious zealots who consider it a duty worthy of their holy calling to attach shameful explanations to innocent opinions, then I am confident that their judgment will have precisely the opposite effect among reasonable people. Besides, people will not deprive me of the right which Descartes enjoyed in his time among disinterested critics when he ventured to explain the development of world bodies from merely mechanical laws. I will therefore quote from the author of Universal World History (1): "Thus we can do nothing other than believe that the attempt of that philosopher who endeavored to explain the development of the world in a certain time from confused matter simply through the continuation of a movement once impressed on it using a few easy and universal laws of motion, or of others who since then have, with more approval, attempted the same thing through the primordial inherent properties of matter, is far from being worthy of punishment or degrading to God, as many have imagined, since in this way a higher idea of His infinite wisdom is far more likely to be brought about." I have sought to clear away the difficulties which seem, from a religious point of view, to threaten my propositions. There are some equally significant difficulties with respect to the subject matter itself. If it is immediately true, people will say, that God has given the natural forces a hidden ability to develop on their own out of chaos a perfect world order, will human understanding, which is so stupid in the commonest circumstances, be able to investigate hidden properties in such a massive enterprise? Such an undertaking amounts to much the same thing as when people say: Give me only the material, and I will create a world out of it for you. Can you learn nothing from the weakness of your insights, which are shamed by the most insignificant things which come into our mind daily and close by, that it is vain to discover the infinite and what was happening in nature even before there was a world? I demolish this difficulty, for I clearly show that of all the attempts which could be devised to learn about nature, this very endeavor may be the one in which we can most easily and surely go right to the origin. For this very reason among all problems of research into nature, none will be resolved more correctly and certainly than the true constitution of the planetary structure on a large scale, the laws of motions, and the inner workings which drive all planetary orbits, in which Newtonian philosophy can provide such insights that we find nothing like them in any other part of philosophy. For just this reason, I maintain that among all the natural phenomena whose first cause we investigate, the origin of the planetary system and the production of the heavenly bodies, together with the cause of their movement, is the one which we may hope to consider reliably from first principles. The reason for this is easy to perceive. The heavenly bodies are round masses with the simplest development which a body whose origin we are exploring can ever have. Their movements similarly are clear. They are nothing other than a free continuation of an impetus impressed upon them once, a motion which, combined with the force of attraction of the body at the mid-point, becomes circular. Above them the space in which they move is empty; the in-between distances, which separate them from each other, are uncommonly large, and everything is laid out for undisturbed motion as well as for clear observation of them in as manifest a way as possible. In my view, we could say here with certain understanding and without presumption: Give me the material, and I will build a world out of it! That is, give me the material and I will show you how a world must come into being out of it. For if the material present is endowed with an inherent power of attraction, then it is not difficult to establish the cause which could have led to the arrangement of the planetary system, considered on a large scale. We know what is involved for a body to acquire a spherical shape. We grasp what is required for freely suspended spheres to take on a circular orbital movement around the middle point towards which they are attracted. The position of the orbits relative to each other, the harmony in the arrangement, the eccentricity, everything can arise from the simplest mechanical causes, and we may hope with confidence to discover them, because they can be established on the easiest and clearest principles. However, can we boast of such advantages for the smallest plant or insect? Are we in a position to say, give me the material, and I will show you how a caterpillar could have developed? Do we not remain here on the bottom rung because of our ignorance of the true inner constitution of things and of the development inherent in the multiple elements in it? Thus, people must not let themselves be surprised when I venture to say that we will be able to understand the development of all the cosmic bodies, the causes of their movements, in short, the origin of the entire present arrangement of the planetary system, before we completely and clearly understand the development of a single plant or a single caterpillar on mechanical principles. These are the reasons on which my confidence rests that the physical part of natural philosophy gives us the hope that in future it will have the same perfection to which Newton raised the mathematical part of the subject. Next to the laws according to which the arrangement of the cosmic structure stands in its present state perhaps there are no others in the entire study of nature so capable of such mathematical accuracy as these laws by which it has developed, and without doubt the hand of an experienced mathematician would find working these fields not unproductive. Now that I have allowed myself to promote a favorable reception for the subject I am examining, I will be permitted briefly to explain the way I have dealt with it. The first part is concerned with a new system for the structure of the cosmos on a large scale. Mr. Wright from Durham, whose essay I learned about in the Hamburg Freie Urteile for the year 1751, first gave me the occasion to consider the fixed stars, not as a scattered confusion without perceptible rules, but as one system with the closest similarity to a planetary system. Thus, just as in the latter the planets are located very near to a common plane, the fixed stars are related as closely as possible to a certain plane which must be imagined drawn through the entire heavens. And in their densest accumulation on this same plane they project that band of light called the Milky Way. I have become convinced that, because this zone illuminated by countless suns is very precisely structured in the shape of a very large circle, our sun must similarly be located very near this large interconnecting plane. While I was exploring the cause of this structure, I have found it very probable that the so-called fixed or firm stars could really be slowly moving, wandering stars of a higher order. To endorse what will be found about this concept later in its own section, I will here only quote a passage from a text by Bradley concerning the movement of the fixed stars: "If we wish to judge the result of a comparison between our best contemporary observations and earlier ones with tolerable accuracy, then some fixed stars really have changed their position with respect to each other and, indeed, in such a way, that we see that this is not the result of some movement in our planetary system, but that it can only be ascribed to a movement of the stars themselves. Arcturus readily provides strong proof of this point. For when we compare the present declination of Arcturus with the same declination as determined by Tycho as well as by Flamsteed, we will find that the difference is greater than we can assume to have arisen from the inaccuracy of their observations. We have reason to suppose that other examples of a similar phenomenon must occur among the large number of visible stars, because their positions relative to each other could have altered for various reasons. If we imagine that our own solar system changes its position relative to absolute space, then after a certain time has gone by, this will give rise to a perceptible change in the angular distance of the fixed stars. And because in such a case this will have a greater effect on the positions of the nearest stars than on the positions of the distant ones, then their positions will appear to change, although the stars themselves remain immovable. If, by contrast, our own planetary system stands still and some stars really do move, these will similarly change their apparent position, and the apparent movement will be greater the closer the stars are to us or the more the direction of their motion is arranged so that we can perceive it. Now, since the positions of the stars could thus be altered by so many different causes, when we consider the astonishing distances at which some of them are indubitably located, it will take the observations of several generations to determine the laws for the perceptible alterations of even a single star. It must be even more difficult to establish firm laws for all the most remarkable stars." I cannot precisely determine the boundaries between Mr. Wright's system and my own, nor in what parts I have merely copied his design or developed it further. However, I had very good reasons to develop one aspect of the design considerably. I took into account the species of nebulous stars, which Maupertuis considered in his treatment of the shape of the stars and which display more or less open elliptical shapes (2), and I easily convinced myself that they could only be an accumulation of many fixed stars. The fact that these shapes, when measured, were always round tells me that here there must be arranged an unimaginably numerous host of stars and, further, that they are around a common mid-point. Otherwise their free positioning in relation to each other would display a wholly irregular shape, not something measurable. I also perceived that they must be located in a unified system and especially that they must be restricted to a single plane, because they are not circular but elliptical in shape, and that because of their pale light they are located incredibly far away from us. What I have concluded from these analogies the discussion will itself present to the unprejudiced reader's understanding. In the second part, which contains the subject most germane to this dissertation, I endeavor to develop the arrangement of the cosmic structure from the simplest condition of nature merely by mechanical laws. If, for those who are shocked at the daring of this undertaking, I may venture to propose a certain order in the manner with which they honour my ideas by testing them, I would request that they first read through the eighth section, which, I hope, will prepare their judgment for a correct insight. Meanwhile, when I invite the well-disposed reader to examine my opinions, I am justly concerned that, since hypotheses of this sort commonly are considered no better than philosophical dreams, it is a sour pleasure for a reader to resolve to undertake a careful investigation on his own into the histories of nature and patiently to follow the author through all the turns by which he moves around the difficulties which he runs into, so that at the end the reader laughs at his own credulity, like those who look at the London Market Crier (3). Now, I dare to promise that, if the reader will, as I hope, be convinced by the preparatory chapter placed at the start to undertake such a physical adventure based on such plausible assumptions, he will not meet, as he continues on his way, as many crooked diversions and impassable obstacles as he is perhaps worried about at the beginning. In fact, I have rejected with the greatest care all arbitrary fictions. After I place the world in the simplest chaos, I have applied to it no forces other than the powers of attraction and repulsion, so as to develop the great order of nature. These two forces are both equally certain, equally simple, and at the same time equally primal and universal. Both are taken from Newtonian philosophy. The first is now an incontestably established law of nature. The second, which Newtonian philosophy perhaps cannot establish with as much clarity as the first, I here assume only in the sense which no one disputes, that is, in connection with the smallest distributed particles of matter, as, for example, in vapours. From such simple grounds as these, I have produced the system which follows in an unaffected style and without imagining any consequences other than those which the reader's attentiveness must observe entirely on its own. Finally, I may be permitted to provide a short explanation concerning the value of the propositions which will appear in the following theory and according to which I hope to be assessed by reasonable judges. We evaluate an author fairly by the same stamp which he impresses on his own work. Thus, I hope people will demand from the different parts of this dissertation no stronger validity for my opinions that what I myself establish for them in the scale of values. Generally the greatest geometrical precision and mathematical certainty can never be demanded from a treatise of this sort. If the system is based upon analogies and harmonies in accordance with the rules of credibility and a correct way of thinking, then it has done enough to attain its goal. I believe I have reached this level of quality in some parts of this dissertation, as in the theory of the system of fixed stars, the hypothesis about the composition of the nebulous stars, the general design for the mechanical development of the cosmic structure, in the theory of Saturn's ring, and in some others. Elsewhere the treatment is less persuasive, as, for example, the determination of the relationships of the eccentricity, the comparison of the masses of the planets, the various deviations of comets, and some others. Therefore, when in the seventh section I pursue the consequences of this theory as far as possible, attracted by the fecundity of the system and the pleasing nature of the greatest and most awesome subject imaginable, always on the theme of analogy and a reasonable credibility, although with a certain boldness, and when I propose to the power of imagination the infinite nature of the entire creation, the development of new worlds and the destruction of old ones, the unlimited space of chaos, I hope that people will be sufficiently indulgent to the attractive charm of the subject and the pleasure which we have in witnessing the harmony in a theory on a large scale not to judge according to the strictest geometrical precision, which, in any case, does not occur in a theory of this sort. I await just the same fairness with respect to the third part. There people will come across something more than merely arbitrary, although always something less than certain. [Back to Table of Contents] Universal Natural History and Theory of Heaven First Part Outline of a Systematic Arrangement of the Fixed Stars and of the Vast Number of Such Systems of Fixed Stars Is the great chain, that draws all to agree, And drawn supports, upheld by God, or thee? (Pope) Short Outline of the Necessary Fundamental Principles of Newtonian Philosophy Required for an Understanding of the following Theory (4) Six planets, including three with accompanying satellites, move in an orbit around the sun at the mid-point: Mercury, Venus, the earth with its moon, Mars, Jupiter with four satellites, and Saturn with five. These, together with the comets which move toward the sun from all sides in very long orbits, make up a system called the Solar System or also the planetary world structure. The fact that the movement of all these bodies takes the form of a circle and returns back on itself presupposes two forces which are equally necessary for any sort of theory, namely, a projectile force, by which at every point of their curved linear movement the bodies would continue on a straight line and disappear into the infinite distance unless another force, whatever it may be, constantly required them to leave this path and move on a curved track around the mid-point of the sun. This second force, as geometry itself has established with certainty, always aims at the sun and is therefore called the sinking force, the centripetal force, or also the force of gravity. If the orbits of the celestial bodies were exact circles, then the very simplest breakdown of the compounded curved movements would reveal that a continuous impulse towards the central point would be required for the arrangement. However, although the movements of all planets and comets are ellipses in which the sun is located at a common focal point, higher geometry with the help of Kepler's model (according to which the radius vector or the line drawn from the planet to the sun always cuts out on its elliptical path an area proportional to the time) immediately establishes with unequivocal certainty that a force must constantly draw the planet throughout its orbital path towards the mid point of the sun. This sinking force, which governs throughout the entire space of the planetary system and directs itself to the sun, is also an accepted natural phenomenon. Equally clearly demonstrated is the law according to which this force extends from the mid-point of the sun into the far distances. It always decreases inversely as the square roots of the distance from the centre increases. This rule is derived infallibly from the time which the planets need at different distances to complete their orbits. These times are always in a ratio to the square root of the cubes of their average distance from the sun. From this we deduce that the force which pulls these cosmic bodies to the mid-point of their orbits must decrease inversely as the square of the distance. This very same law which governs the planets in their movements around the sun occurs also in connection with small systems, namely, with those which are made up of the moons moving about their main planet. Their orbital times are in exactly the same way proportional to the distance and establish a relationship of the force which causes sinking towards the planet, which is the same as the one by which the planet is pulled towards the sun. All this, derived from the most infallible geometry and uncontested observations, has been placed forever beyond contradiction. From this arises now the idea that this sinking force may be exactly the same impetus which is called heaviness on the surface of the planet and which diminishes with the distance from the surface gradually according to the above-mentioned law. We see this from the comparison of the quantity of heaviness on the surface of the earth with the force which pulls the moon to the mid-point of its orbit. These stand in relation to each other just as the force of attraction in the entire planetary system, namely, in inverse proportion to the square of the distance. Hence people call this frequently reported force gravity. Moreover, because the idea is highly probable that if a present effect occurs only in proportion to the distance to a certain body and if the direction of this effect is related as precisely as possible to this body, then this body may be, however this occurs, the cause of the effect. Therefore, we have sufficient reason to think that the universal downward movement of the planets towards the sun is an attribute of the power of attraction of the sun and to ascribe this power of attraction in general to all the celestial bodies. If a body is left free to the influence of this impulse which drives it to sink toward the sun or any other planet, then it will fall towards it with a constantly accelerating motion and soon will be united with that same mass. However, if it gets a force directing it to the side, then, if that force is not powerful enough to achieve an exact equilibrium with the sinking force, the body will sink down to the central mass with a curved movement. And if, before the sinking body touches the outer surface of the central mass, the impulse impressed on it has grown at least strong enough to shift it from the vertical line about half the thickness of the central mass, then it will not touch this surface but, after it has swung closely around it, will, thanks to the velocity achieved in its fall, be raised up high again just as far as it fell, so as to continue its path in a constant orbital movement. Thus, the difference between the orbital paths of the comets and the planets consists in the sideways deviation in opposition to the force which drives them to fall. The more these two forces approach an equilibrium, the more the orbit will become circular in shape; the more unequal they are, the weaker the projectile force in relation to the force pulling to the centre, then the longer the orbit, or, as we say, the more eccentric the orbit is, because the celestial body in one part of its path comes far closer to the sun than in another. Because nothing in all nature is exactly balanced, no planet has an entirely circular motion. However, the comets deviate the most from a circular orbit, because at their first location the sideways impetus influencing them was the least proportional to the force pulling them to the centre. In this treatise I will often use the expression a systematic arrangement of the cosmic structure. So that people will have no difficulty clearly imagining what this term might mean, I will explain it briefly. Strictly speaking, all the planets and comets which belong to our cosmic structure already form a system by the fact that they rotate around a common central body. However, I take this term in an even narrower sense, in which I consider the more precise relationships which have united them with each other in a regular and uniform way. The orbits of the planets are, in relation to each other, as nearly as possible on a common plane, namely, on the extended equatorial plane of the sun. The deviations from this rule occur only in connection with the outermost borders of the system, where all movements gradually cease. When therefore a certain number of cosmic bodies, ordered around a common mid-point and moving around it are at the same time restricted to a certain plane, so that they have minimal freedom to deviate on both sides of this plane, and when the deviation occurs gradually only with those which are furthest distant from the mid-point and thus have fewer interconnections than the others, then I say that these bodies are bound together in a systematic arrangement. On the Systematic Arrangement of the Fixed Stars The theory of the general arrangement of the cosmic structure has not achieved any remarkable progress since the time of Huygens. At this time we know no more than we already knew then, namely, that six planets with ten companions all have their circular orbits arranged almost on a single plane, that they, together with the eternal comets, which run riot in all directions, make a single system, whose mid-point is the sun, towards which everything sinks, around which their movements run, and from which they all are illuminated, warmed, and kept alive, and finally that the fixed stars are just so many suns, the mid-points of similar systems, in which everything may be set up in just as large and orderly a way as in our system and that the infinite space swarms with cosmic systems, whose number and excellence is connected to the infinite nature of their Creator. The systematic arrangement which occurs in the union of the planets which move around the sun disappeared altogether in the crowd of fixed stars. And it seemed as if the rule-governed relationship encountered in miniature does not hold sway on a large scale among the structures of all the worlds. The fixed stars were subject to no law, by which their paths were confined relative to each other, and we saw all heaven and the heaven of all heavens without order and without design. Since human curiosity limited itself in this way, we did nothing further, other than to derive from this state the immensity of the One who had revealed Himself in such inconceivably huge works and to admire Him. Wright, an Englishman from Durham, stumbled across a lucky idea, which he himself does not seem to have developed into anything insightful, for he did not make enough observations to produce something useful. He looked at the fixed stars not as a disorganized, scattered swarm without design but saw them in total as a systematic arrangement in a general stellar interrelationship with reference to the principal spatial plane which they occupy. We wish to develop the idea which he came up with and to try to bring out fully its implications, so that it can generate fertile consequences. The complete confirmation of these will be something left for future ages. Anyone who gazes at the starry heaven on a clear night will notice the bright band which presents a steady light through the crowd of stars, which are more numerous there than elsewhere and which perceptibly lose themselves in the huge expanse. People have called this band the Milky Way. Because of the structure of this recognizable and distinct area in the sky, it is remarkable that observers of the Heavens were not long ago prompted to derive from it certain conclusions about the locations of the fixed stars. For we see that the band is organized in a huge circle and in a continuous arrangement taking up the entire sky. These two factors are so precisely determined and, in comparison with the uncertainty of chance, with such recognizable indicators, that from them long ago attentive astronomers should naturally have been motivated to trace accurately the explanation for such a phenomenon. The stars are not placed on the apparently hollow sphere of the heavens, but from our point of view stand at some distance from each other, some further than others, disappearing into the depths of the skies. From this phenomenon it follows that, at those distances where they are located one behind the other in relation to us, they do not occur in an equal scattering in every direction, but must be arranged on some plane which goes through our viewpoint. They are located as close as possible to this plane. This relationship is such an unambiguous phenomenon that the other stars, which are not included in the white band of the Milky Way, are themselves observed to be that much closer together and more dense, the nearer they are located to the circle of the Milky Way. Thus, of the 2000 stars which the naked eye perceives in the sky, we find the largest number in a relatively narrow area in the middle of which is the Milky Way. Now, if we imagine a flat plane drawn through the starry heavens and extending an unlimited distance and if we assume that all the fixed stars and all the solar systems have a common spatial relationship to this plane, so that they are closer to it than to any other areas, then the eye which is located on this common plane, as it looks out into this field of stars, into the hollow spherical surface of the firmament, will see the thickest crowd of stars in the direction of the drawn plane, in the form of an area illuminated with more lights. This band of light will sweep out in the shape of huge circle, if the onlooker's viewpoint in on the plane itself. This area will be full of stars. Because of the undifferentiated smallness of bright points, a single one of which escapes the eye, and because of the apparent density of a uniform white gleam, it will look, in a word, like a Milky Way. The rest of the heavenly stars, whose relationship with the drawn plane becomes less and less apparent or which are also located closer to the observer's position, will seem to be more scattered, although their accumulation will be precisely related to this plane. From this finally it will follow that, because from our solar system the system of fixed stars will be seen in the shape of a very large circle, our solar system will be in the same large plane and make one system with the fixed stars. In order that much better to explore the arrangement of the common interrelationship governing this cosmic structure, we wish to try to discover the cause which has arranged the positions of the fixed stars in this way on a single common plane. The Sun does not limit the extent of its powers of attraction to the narrow region of the planetary system. According to all observation, this power extends an infinite distance. The comets which go far above Saturn's orbit are forced by the sun's powers of attraction to turn back and move in orbits. Whether it is more likely for the nature of a force apparently incorporated into the essence of matter to act without limits and whether, in addition, it will be really recognized as such by those who assume Newton's principles, we wish only to concede that this power of attraction of the sun extends approximately to the nearest fixed star and that the fixed stars act on each other as just so many suns in the same way. Thus, it follows that the entire host of fixed stars is forced to come closer together through this power of attraction, so that all the world systems are in a situation where sooner or later they fall into one clump, through this reciprocal moving closer together, which is continuous and unhindered, unless these systems are saved from this disaster by forces which pull away from the central point, as with the spheres in our planetary system. These forces prevent the heavenly bodies from falling directly and, working together with the forces of attraction, bring about the timeless orbits. Thus the structure of creation will be preserved from collapse and has been created to last eternally. Thus, all the suns in the firmament have an orbiting motion, either around one common central point or around many. But with them, we can everywhere apply the analogy of what we observe about the orbital path of our own solar system, namely, that just as that very cause which subjects the planets to a force moving them away from the centre, through which they maintain their orbits, has organized their orbital paths so that they are all on a single plane, so also the cause, whatever it might be, which has given the suns and so many wandering stars of the higher world structure the force of their orbits has also brought their orbits as much as possible into one plane and has worked to limit deviation from this plane. According to this conception, we can picture the system of fixed stars to a certain extent by means of the planetary system, if we magnify the latter infinitely. For if instead of six planets with their ten satellites we assume many thousands of similar bodies, and instead of the twenty-eight or thirty comets which we have observed, we assume a hundred or a thousand times more of them, and if we think of these bodies as generating their own light, then to the eye of the observer who looks out from earth it would appear as it does with the fixed stars of the Milky Way. For the above-mentioned planets, because of their close relationship to the common plane, would display to us on our earth located in exactly the same plane an area made up of countless stars densely lit, in the shape of a very large circle. This band of light would have a sufficient number of stars everywhere, although, according to this hypothesis, as moving stars, they are not fixed to a single spot. For, because of their movement, there would always be enough stars on anyone side, even though other stars had moved from that location. The width of this illuminated area, which projects a sort of zodiac, will be set by the different levels of deviation of designated erratic stars from the reference plane and by the inclination of their orbits in relation to this same plane. Since most of them are near this plane, their number will appear more scattered in relation to the extent they are distant from it. However, the comets, which occupy all regions without distinction, will cover the field of heaven on both sides. The shape of the heaven of fixed stars thus has no cause other than the same systematic arrangement on a grand scale as the cosmic structure of the planetary system on a small scale. All the suns in them make up one system, whose common connecting plane is the Milky Way. Those which are the least related to this plane will be seen to the side of it; for that reason however, they are less dense, more widely scattered, and less frequent. They are, so to speak, comets among the suns. This new theory, however, attributes a forward motion to the suns, and yet everyone acknowledges that they are motionless and that they have been fixed in their positions from the start. The name which the fixed stars have acquired from this seems confirmed and unambiguous because of all the centuries of observation. This difficulty, if soundly based, would destroy the proposed theory. But this lack of movement, when we consider it, is only apparent. It is either only an exceeding slowness, caused by the enormous distance of their orbits from the common mid-point or an oversight brought about by the distant location of the observer. Let us estimate the plausibility of this notion by calculating the movement of one of the fixed stars located very close to our sun, assuming that our sun is the central point of its orbit. If, following Huygens, we assume that the distance of this star is over 21000 times greater than the distance of the sun from the earth, it then follows from the established law of the time of orbiting bodies, which is proportional to the square root of the cube of the distance from the mid-point, that this star must take more than one and a half million years to go around the sun and, what is more, in 4000 years it would have moved forward only about one degree. Now, perhaps only very few fixed stars are as close to the sun as Huygens assumed for Sirius. Thus, the distance of the rest of the heavenly host perhaps exceeds by far the distance of Sirius, and therefore most of them would take an unusually longer time for such periodic orbits. From this it is also more probable that the motions of the suns in the celestial stars go around a common point whose distance is much further away, and the forward motion of the stars can hence be exceedingly slow. So we can probably assume that all the time which human beings have been keeping records of celestial observations has been insufficient for them to notice the change which has taken place in these stellar positions. We should not, because of this, give up hope that we will discover this change in time. To achieve that will require subtle and careful observations, together with a comparison of widely distant observations. We must direct these measurements especially at the stars of the Milky Way (5), the main plane of all movement. Bradley has observed the almost imperceptible movements of the stars. The ancients marked stars in particular places in the sky, and we see new ones in other places. Who knows that these ones have not just changed position? The excellence of the instruments and the perfecting of our knowledge of the stars give us ground to hope for the discovery of such remarkable and important observations (6). The credibility of the very issue supports this hope on the ground of nature and the analogy so well, that it can stimulate the attentive work of scientists to bring it to completion. The Milky Way is, so to speak, also the zodiac of new stars, alternately appearing and disappearing in this region in a way hardly matched in any other celestial area. If this alteration in their visibility proceeds from their periodic moving further away and closer to us, it seems clear from the proposed systematic arrangement of the stars, that such a phenomenon must, in all likelihood, be seen only in the region of the Milky Way. For there are stars there moving in very elongated orbits around other stars, as satellites move around their main planets. The analogy with our planetary system, in which only heavenly bodies near the common plane of movement have a companion moving around them, requires that only the stars in the Milky Way have suns orbiting around them. I am coming to that part of the proposed theory which makes it most particularly attractive because of the sublime picture it presents of creation's plan. The series of ideas which has led me to it is short and simple. It consists of the following. If a system of fixed stars, all spatially related to a common plane, exactly as we have sketched out the Milky Way, is so far distant from us that all perception of individual stars making up the system is no longer possible, even with a telescope, if the distance of this system has exactly the same relationship to the distance of the stars in the Milky Way as the latter has to the distance of the sun from us, in short, if such a world of fixed stars is seen at such an immeasurable distance from the eye of the observer located outside this world, then this world will appear in a small angle as a tiny and weakly lit area, with a circular shape if its plane is oriented directly in the line of sight and elliptical if it is viewed from the side. The weakness of the light, the shape, and the recognizable extent of its diameter will be clearly distinguish such a phenomenon, when present, from all the stars which are seen individually. We do not need to search a long time for this phenomenon among the observations of the astronomers. It has been clearly confirmed by different observers. People have wondered about its strangeness, have made assumptions, and have subscribed to sometimes wonderful imaginary images and sometimes plausible ideas, which, however, just like the former, had no basis. We are talking about the nebulous stars or, rather, a type of them, which Maupertuis wrote about as follows (7): there are small planets whose light is somewhat more than the darkness of the empty heavens, which all are alike in the fact that they display more or less open ellipses; but their light is much weaker than any other that we are aware of in heaven. The author of the Astrotheology imagines than these are openings in the firmament through which he believed he saw heavenly fire. A philosopher of illuminating insights, the above-mentioned Maupertuis, in thinking about the shape and the recognizable diameter of these stars, considers that they are astonishingly large celestial bodies which display an elliptical shape because of the large flattening caused by their rotation, when viewed from the side. It is easy to be convinced that this last explanation cannot hold. Because this kind of nebulous stars must undoubtedly be as far away from us as the other fixed stars, not only would their size be astonishing (for in this respect they would have to exceed by a factor of many thousands the largest star), but the strangest point of all would be that with this extraordinary size, made up of self-illuminating bodies and suns, these stars should display the dimmest and weakest light. Much more natural and comprehensible is the idea that there is no such single huge star but systems of many stars, whose distance makes them appear in such a narrow space, that the light, which cannot be seen for each individual star because of the countless crowd of them, comes out in a uniform pale glow. The analogy with the solar system in which we find ourselves, their shape, which is exactly as it must be according to our theory, the weakness of the light, which this previously mentioned distance requires, all these endorse perfectly the idea that these elliptical figures should be taken as exactly the same world structures and, so to speak, as Milky Ways, whose structure we have just gone through. And if suppositions in which analogy and observations are in full agreement and support each other have the same value as formal proofs, then we must take the certainty of this system as demonstrated. Now, the attentiveness of the astronomers has sufficient motivation to concern itself with this matter. The fixed stars, as we know, are all connected to a common plane and thus create a coordinated totality, a world of worlds. We see that in the immeasurable distances there are more such star systems and that creation in the entirely of its infinite extent is everywhere systematic and interconnected. We could further suppose that these higher world orders are not unconnected to each other and through their mutual relationship establish once again an even more immeasurably great system. In fact, we see that the elliptical shapes of these sorts of nebulous stars, which Maupertuis mentions, have a very close relationship to the plane of the Milky Way. Here a wide field stands open for discovery, for which observation must provide the key. The properly named nebulous stars and those about which there is a dispute whether we should call them nebulous must be investigated and tested according to the guidelines of this theory. If we view the parts of nature according to a design and a plan we have discovered, then certain characteristics reveal themselves which otherwise will be overlooked and remain hidden, when observation squanders its time on all objects without any guidance. The theory which we have proposed opens up for us a view of the infinite field of creation and offers an idea of the work of God appropriate to the infinite nature of the Great Masterbuilder. If the size of a planetary system in which the Earth is hardly seen as a grain of sand fills the understanding with wonder, how delightfully astonished we will be when we examine the infinite crowd of worlds and systems which fill the totality of the Milky Way. How much greater this wonder when we know that all these immeasurable orders of stars once again create a numbered unity, whose end purpose we do not know and which is perhaps, like the previous one, inconceivably large and yet, once again, still a unified system of a new numbered series. We see the first links of a progressive relationship of worlds and systems, and the first part of this unending progression allows us to recognize what we should assume about the totality. Here there is no end, but an abyss of a true infinity, in which all capacity of human thought sinks, even when it is uplifted with the help of mathematics. The wisdom, goodness, and power which has revealed itself is limitless and, to exactly the same extent, fruitful and busy. The plan of its revelation must, therefore, be, just like it, without borders and timeless. However, there are important discoveries to be made, and not just in large things serving to expand the ideas we can formulate about the magnitude of creation. In small things there is no less undiscovered, and we see even in our solar system the links of a system, which stand immeasurably far from one another and between which we have not yet discovered the intermediate parts. Saturn is the outermost of the wandering stars which we known about. Must there be no more planets between Saturn and the least eccentric comet which perhaps comes down to us from a distance ten or more times removed, a planet whose orbit could approach more closely a comet's orbit than Saturn does? And must not yet other planets be changing into comets by means of a series of intermediate types approximating the composition of comets and linking together the family of planets with the family of comets? The law according to which the eccentricity of the planetary orbits stands in direct proportion to their distance from the sun supports this assumption (8) The eccentricity in the movement of the planets increases with the distance of the planet from the sun, and the furthest planets therefore come closer to the condition of comets. We can also assume that there are still other planets even beyond Saturn which are even more eccentric and therefore more closely akin to comets, thanks to a continual gradation which finally turns planets into comets. The eccentricity of Venus is 1/125th of the semi-axis of its elliptical orbit; in the case of Earth, the eccentricity is 1/58th; in the case of Jupiter, it is 1/25th, and in the case of Saturn 1/17th. Thus, the eccentricity visibly increases with the distances. It is true that Mercury and Mars are exceptions to this rule, because, according to the law, their eccentricity is much greater than for the extent of their distance from the sun. But we will learn in what follows that the very same cause which made some planets develop a smaller size also deprived them of the impulse required for a circular path, with the result that they were pulled into an eccentric movement. As a result, they were left incomplete in two respects. Is it not a probable consequence that the increase in the eccentricity of the cosmic bodies located immediately beyond Saturn will be approximately proportional to the ones beneath, and that the planets are related to the family of comets through a less abrupt gap (9)? For it is certain that this very eccentricity is the most important difference between the comets and the planets. The comet's tail and its misty spheres are only consequences of eccentricity. Similarly, the very cause, whatever it may be, which has given the celestial bodies their orbital paths, because of the greater distances not only grows weaker in making the circular momentum equal to the downward force, thereby allowing eccentric movements, but also for this very reason is less able to bring the orbits of these spheres into the common plane on which the lower bodies move. Thus is produced the deviation of the comets in all regions. According to this hypothesis, we would still perhaps hope for the discovery of new planets beyond Saturn, which would be more eccentric than Saturn and also closer to the nature of comets. But for this very reason we would be able to see them only for a short time, when they approach the sun. This factor, the smaller extent of their approach, and the weakness of their light have hindered their discovery and must make that difficult in future. If we wanted, we could call the last planet and the first comet the one whose eccentricity was so large that in its approach to the sun it intersected the orbit of the nearest planet to it, perhaps also with Saturn's. [Back to Top of Part One] [Back to Table of Contents] Universal Natural History and Theory of Heaven Second Part Concerning the first condition of Nature, the development of the celestial bodies, the causes of their movement and their systematic interrelationship both with the structure of particular planets and also with the entire creation. See plastic Nature working to this end, The single atoms each to other tend, Attract, attracted to, the next in place Form's and impell'd, its neighbour to embrace. See Matter next, with various life endu'd Press to one centre still, the gen'ral Good. Pope Section One Concerning the Origin of the Planetary World Structure in General and the Causes of Its Movements So far as concerns the reciprocal relationships which the parts of the cosmic structure have among themselves and through which they reveal their original cause, observation of this arrangement displays two aspects, both of which are equally probable and worthy of consideration. On the one hand, if we think of the fact that six planets with ten companions describe orbits with the sun at the mid-point, that all move in the same direction, the very same as the axial rotational of the sun itself, which governs all their orbits though the power of attraction, that their orbits do not deviate far from a common plane, namely, the extrapolated equatorial plane of the sun, that among the furthest celestial bodies belonging to the solar system, in the region where the common cause of movement was, according to our hypothesis, not so strong as in the regions close to the mid-point, deviations from the precision of this condition occur, which are significantly related to the lack of impressed motion, if, I say, we consider all this interconnection, then we will come to believe that one cause, whatever it may be, had a pervasive influence throughout the entire system and that the conformity in the direction and position of the planetary orbits is a consequence of a harmony which they must have had with that material cause through which they were set in motion. On the other hand, if we consider the space in which the planets of our system orbit, then we find it is completely empty and deprived of all material stuff which could have subjected these celestial bodies to a common set of influences and brought harmony to their movements (10). This emptiness has been established with more perfect certainty and is possibly more likely than the previous condition. Swayed by this matter, Newton could not point to any material cause which must maintain by its extension into the space of the planetary system the commonality of movements. He maintained that the unmediated hand of God had set up this order without the use of any natural forces. Considering the matter impartially, we see that the reasons here on both sides are equally strong. And they have an equal value as completely certain. However, it is also just as clear that there must be an theory which can and should unite these two apparently widely conflicting reasons and that in this theory we must seek the true system. We wish briefly to indicate that theory. In the present arrangement of space, in which the spheres of all the planetary system move around, there is no material cause present which could impress itself on or govern their movements. This space is completely empty, or at least as good as empty. Thus it must have in earlier times been differently constituted and full of matter capable of conferring movement on all the celestial bodies located there and of bringing them into harmony with its motion and, as a consequence, into harmony with each other. When the power of attraction brought unity to all of space and collected all the scattered matter in particular clusters, the planets must have then freely and unchangingly continued the orbital movement, once impressed upon them, in an unresisting space. The reasons for the first-mentioned probability absolutely require this notion . And since there is no third possibility between the two, we can approve this concept as superior, so that it can be given a higher status than a plausible hypothesis. If we wished to be long winded, we could, with a series of successive inferences in the manner of a mathematical demonstration, with all the display that this involves and with an even greater plausibility than its introduction in physical subjects customarily elicits, finally arrive at the proposal itself, which I will set down concerning the origin of the cosmic structure. But I would rather present my opinions in the form of a hypothesis and leave it to the reader's insight to put it to the test, than render its validity suspect because of the appearance of a devious demonstration, something which might captivate the ignorant but lose the approval of those who understand. I assume that all the matter making up the spheres belonging to our solar system, all the planets and comets, at the origin of all things was broken down into elementary basic material filling the entire space of the cosmic structure around which these bodies now move. If we consider this state of nature in and of itself, without reference to a system, it seems to be only the simplest which can follow upon nothing. At that time nothing had yet developed. The incorporation of heavenly bodies separate from one another, with their distance from each other controlled according to the power of attraction, and their shape, arising from the equilibrium of the collected materials, are a later condition. Nature, on the immediate edge of creation, was as raw and undeveloped as possible. Only in the essential properties of the elements which made up the chaos can we perceive the sign of that perfection which nature has from its origin, since its being is a consequence arising from the eternal idea of the Divine Understanding. The simplest and most universal characteristics, apparently designed without purpose, had in their most rudimentary state an impulse to develop to perfection by natural means the material stuff, which apparently was merely passive and lacking form and organization. The difference in the types of elements by itself led to the movement of nature and to the development of chaos in the most noble manner, so that the tranquillity which would have ruled with a universal calm throughout the scattered elements disappeared, and the chaos began to develop itself at points where the particles had a stronger power of attraction. The types of this basic material are undoubtedly infinitely different to match the immeasurable size which nature displays in every direction. The materials with the greatest specific density and power of attraction, which by themselves take up less room and are also rarer, were then more scattered in space than the lighter varieties of material. Elements with a specific density one thousand times greater are a thousand, perhaps a million, times more scattered than those with a lighter mass. These differences must be imagined as infinite as possible. One sort of physical component can exceed another in density in the same way that a sphere drawn with the radius of the planetary system exceeds another sphere with the diameter of the thousandth part of a line. Thus, the heavier sort of dispersed elements will be much further from each other than the lighter ones. The universal tranquillity in space replete in this way lasts only for an instant. The elements have inherent forces which set each other in motion and are, indeed, themselves, an origin of life. The material is under an immediate impulse to develop. The denser type of scattered materials, through the power of attraction, collect from a spherical area around them all the material with a lesser specific gravity. These materials, together with the stuff which they have united with them, are assembled in the points where the small pieces of an even denser type are located, and these again to even denser points, and so on. When we think about this idea of a self-developing nature throughout the entire extent of chaos, we will easily see that all the consequences of this process will finally consist of the assembling of different clusters, which, according to the way in which they developed, would be calm and eternally motionless because of the equilibrium in the force of attraction. But nature has still other forces in store, which manifest themselves especially when the material is dispersed in fine particles, so that these particles repel each other and by their conflict with the power of attraction induce movement, which is, as it were, the enduring life of nature. This force of repulsion reveals itself in the elastic nature of vapours and the diffusion of all gasses and from objects with a strong smell. It is an uncontested feature of nature. Because of it, the elements sinking towards the point of attraction will move each other sideways from their vertical movement, and the straight linear descent will end up as an orbital movement with the point towards which they were sinking at the centre. In order clearly to grasp the development of the cosmic structure, we want to limit our observation of the infinite essence of nature to a particular system, similar to the one to which our sun belongs. Once we have explored the development of this system, then we will be able to proceed in a similar way to the origin of the higher world order and bring together into one theory the infinite nature of the entire creation. Thus, when a point is located in a very large space where the power of attraction of the elements placed there exerts a stronger influence than at any other points around it, then the basic material stuff of elementary particles in all the surrounding area will sink to this point. The first effect of this general sinking is the development of a body at the mid-point of the forces of attraction which, so to speak, proceeds to grow from an infinitely small seed in rapid stages. As this mass increases, it will, in exactly the same proportion, through its more powerful force move the surrounding particles to unite with it. When the mass of this central body has grown so extensive that the velocity with which it draws the small particles to itself from great distances is diverted sideways by the weak level of the force of repulsion with which these particles interfere with one another, it produces lateral movements, which, thanks to the centrifugal force, are such that they move in a circle around the central body. Thus, large eddies of particles develop, each of which, because of the combination of the force of attraction and the force leading to a sideways rotation describes its own curving path. These sorts of circles all intersect each other, as a result of their large scattering in this space. Meanwhile, these movements, in various ways in conflict with each other, strive naturally to bring each other into equilibrium, that is, into a single state where the movement of one hinders the movement of another as little as possible. This occurs, firstly, because the small particles limit the movement of other particles until they all are moving forward in one direction; second, because the particles restrict their vertical movement, which brings them closer to the centre of the attraction, until the time when they are all moving horizontally, that is, in circles running parallel around the sun at the mid-point. At this stage, they no longer intersect with one another. They maintain constant free circular orbits at the heights where they are suspended, thanks to the equilibrium between the projectile force (centrifugal force) and the force drawing them downwards (centripetal force). Thus, finally only those particles remain suspended in celestial space which have attained through their fall a velocity and through the resistance of other particles a direction by means of which they can continue a free circular movement. In this condition, where all the small particles run around the central body in one direction and in circles arranged in parallel, namely, in free circular movements by means of the required projectile force, the conflict and the collision of the elements disappear. Everything is in the condition of the smallest reciprocal interaction. This result always occurs naturally with materials subject to conflicting movements. It is also clear that from the scattered number of particles a large number must, on account of the resistance through which they seek to bring each other to this state, succeed in attaining such an exact arrangement, although a much greater number do not reach this condition and serve only to increase the cluster of the central body, into which they sink, since they cannot maintain themselves freely at the height where they are suspended, but intersect the circles of the lower particles and eventually through the resistance lose all their movement. Consequently, because of the amount of its assembled material, this body at the mid-point of the attraction will become the main piece of the planetary structure. This is the sun, although at this time it does not yet immediately have that flaming glow, which breaks out on its surface when its development is fully complete. We must also observe that while all the elements of self-developing Nature, as demonstrated, move in one direction around the sun as the mid-point, in the case of such orbits which are set up in a single direction and which occur, so to speak, around a common axis, the rotation of fine material cannot remain in this way, because, according to the laws of the centripetal force, all orbital movements must intersect the mid-point of the force of attraction with the plane of their rotation. Among all these orbits moving in one direction around a common axis, however, there is only one which intersects the mid-point of the sun. Thus, all the material from both side of this imagined axis moves quickly to that circle which goes directly through the axis of rotation at the central point of the common downward movement. This circle is the plane of movement for all the elements orbiting around; as much as possible they accumulate there and, by contrast, leave the regions far away from this plane empty. Those elements which cannot approach so closely to this plane towards which everything is drawn will not be able to maintain themselves indefinitely in those place where they are suspended, but, as they collide with the orbiting elements, will initiate their own fall toward the sun. If we also consider this fundamental material of the planets whirling about in a state where it develops itself through the power of attraction and the mechanical consequence of the general law of repulsion, then we see a space which is contained between two planes standing not far from each other. In the middle of these planes is located the common interconnecting plane, extending from the mid-point of the sun out to an unknown extent. All the particles we can conceive have their mathematically precise circular orbits on this common plane, each proportional to the extent of its distance and to the force of attraction which governs there. Because in such an arrangement they interfere with each other as little as possible, they would remain in this form for ever, if the force of attraction of these particles of basic matter did not then start to have an effect and initiate developments, thus producing the seeds of planets which are to arise. For as the elements moving around the sun in parallel circles take up positions where the distances from the sun are not very different, circles which, because of the equality in the parallel movements, are almost in relative calm in relation to each other, then the force of elements there with an excessive specific power of attraction begins at once a significant process of collecting the nearest particles for the development of a body. As the mass of its growing cluster increases, the power of attraction of this body expands, and elements from a wide area move to combine with it (11). In this system, the development of the planets has this advantage over any other theoretical possibility: the cause of the masses provides simultaneously the cause of the motion and the position of the orbits at the same moment in time. Indeed, even the deviations from the greatest precision in this arrangement, as well as the harmonies, are illuminated. The planets are developed out of particles, which at the heights where they are suspended have precise movements in circular orbits. Thus, the masses formed by their combination will continue exactly the same movement at the same level and in exactly the same direction. This is sufficient to understand why the paths of the planets are approximately circular and why their orbits are on a single plane. Moreover, they would be exactly circular if the distance from which the elements gather in their development were very small and also if the difference in their movements were very insignificant (12). But because the development of a thick planetary cluster involves a wider surrounding area, throughout which the fine basic stuff is scattered in celestial space, the difference in the distances of these elements from the sun and thus, in addition, the difference in their velocities is no longer insignificant. As a result, given this distance in the movements, it would be necessary, in order to maintain on the planet an equilibrium between the centripetal forces and the circular velocity, for the particles which collide with the planet from different distances and with different velocities mutually to offset each other's aberrations. Although this occurs fairly accurately, it is not perfect, and it brings the deviations from circular movement and eccentricity with it (13). Similarly it is easy to see that although the orbits of all planets should properly be in one plane, nevertheless here also we will come across a small deviation, because, as already discussed, the elementary particles located as close as possible to the general plane of movement nevertheless take up some space on either side. It would be a really fortunate coincidence if all the planets should begin to develop exactly half way between these two sides on the plane connecting them, which would already cause some inclination of their orbits relative to each other, although the impulse of the particles from both sides limit this deviation as much as possible, allowing it only within narrow limits. Moreover, we should not wonder about the fact that here we rarely come across the most precise accuracy in the arrangements, as is the case with all natural things, because generally the multiplicity of circumstances involved in every natural condition does not permit an exact regularity. [Back to Top of Section One] [Back to Table of Contents] Part Two Section Two Concerning the Different Densities of the Planets and the Relationship of Their Masses We have shown that the particles of the elementary basic material, distributed equally by themselves in cosmic space, by their sinking downward towards the sun remain suspended in the places where the velocity which they attained in their descent reaches a precise equilibrium in relation to the force of attraction and that their direction would be altered so as to be perpendicular to the radius of the circle, as should be the case with circular movements. However, if we now think of the particles of different specific density at the same distance from the sun, then the ones with a greater specific gravity drive more deeply through the resistance of the other particles toward the sun and will not be diverted from their path as soon as the lighter ones. Thus, their movement will form a circular orbit only at a closer distance to the sun. On the other hand, the elements of the lighter type are diverted from a straight vertical fall earlier and take on a circular movement before they are driven so deep toward the centre. Thus, they remain suspended at a greater distance away. Moreover, they are not able to drive so deeply downward through the space filled with the elements, without the resistance of these elements decreasing their motion, and they will not be able to attain the velocity required for a circular movement closer to the mid-point. And, according to the equilibrium in the movements, the specifically lighter particles will orbit at distances far from the sun; the heavier ones occur, however, at closer distances. The planets which are built out of these elements will therefore be denser when they are nearer the sun than when they are formed from the combination of these atoms far away from the sun. Thus, there is a sort of statistical law which establishes for the material of cosmic space an inverse relationship between the distance from the centre and the density. In the same way, it is easy to grasp that it is not essential that each distance contain only particles of the same specific density. Of the particles of a certain specific type, some are suspended at a greater distance from the sun and attain the necessary permanent circular motion appropriate to their fall at a greater distance. These have moved down toward the sun from further away. On the other hand, those whose original location in the universal distribution of the materials in Chaos was nearer the sun, regardless of the fact that their density is no greater than the former group, will attain a circular orbit closer to the sun. Moreover, since the locations of the materials in relation to the mid-point of their descent is determined not only by the specific gravity of the material but also by its original place in the first calm state of nature, it is easy to see that very different types of material will combine at every distance from the sun, so as to remain suspended there and that, nevertheless, generally we will find the denser material in greater accumulations closer to the mid-point than further away. In general, the masses must be denser in proportion to their closeness to the sun and less dense when their distances away are greater. In the matter of this law governing planetary densities, our system manifests an advantageous comprehensiveness in comparison with all those ideas which people have come up with or even could come up with about the cause. Newton, who established the densities of some planets by calculation, thought that the cause of this relationship according to the established distance was to be found in the appropriateness of God's choice and in the fundamental motives of His final purpose, since the planets closer to the sun must endure more solar heat and those further away must receive less heat, which would not seem to be possibe, unless the planets near the sun were composed of a denser material and those further away of a lighter material. But to perceive the inadequacy of such an explanation does not really require much reflection. A planet (for example, our Earth) is composed of types of material very different from each other. Of these, it was necessary only that the lighter varieties, which will be more deeply penetrated and affected by the same solar working and whose composition has a relationship to the heat generated by the sun's rays, be spread out on the planet's outer surface. But here the fact that the mixture of the remaining material in the total cluster must have this relationship sheds light on nothing at all. Newton was afraid that if the Earth had been in a lower position in the proximity of Mercury, in the sun's rays it would necessarily burn up like a comet and that the Earth's materials have insufficient protection against fire not to become scattered by this heat. But it is much more pertinent that the sun's own material stuff, which is four times lighter than the material making up the Earth would have to be destroyed by fire. Or why is the Moon twice as dense as the Earth, yet still suspended at just the same distance away from the sun as the Earth? Thus, we cannot attribute the proportional densities to the relationship with the sun's heat, without entangling ourselves in the greatest contradictions. We much sooner see that a cause which distributes the planets according to the density of their clusters must have had a relationship to the inner material and not to the material on the surface. This cause would have to establish the relationship with the density only in the total composition, still permitting a differentiation in the materials in one and the same celestial body, without regard to the consequences which it established. Whether some statistical law or other, like the one which will be presented in our theory, can achieve this satisfactorily I leave to the insight of the reader to judge. The relationship of the planetary densities brings with it one more circumstance which corroborates the validity of our theory by completely endorsing the previously proposed explanation. The celestial body standing at the mid-point of other spheres orbiting around it is commonly of a lighter sort than the bodies orbiting most closely to it. The Earth with respect to the Moon and the Sun with respect to the Earth manifest such a relationship vis-ā-vis their densities. According to the proposal which we have laid out, such a condition is necessary. For the lower planets were built up mainly from the excess elementary material which, thanks to the advantage of its density, could have driven right to an area close by the mid-point with the required velocity. By contrast, the body at the very mid-point was put together from totally heterogeneous materials which did not attain the velocity required by the law. Among these, the lighter materials make up the greatest portion. Thus, it is easy to see that, because the celestial body orbiting closest to the mid-point or the one nearest to it has within it, as it were, a selection of the denser forms of material but that the central body has a mixture of all types, without distinction, then the former will be denser than the latter. In fact, the moon has twice the density of the Earth, and the Earth is four times denser than the sun. According to all assumptions, the even deeper planets (i.e., closer to the sun), Venus and Mercury, will exceed these with an even higher density. We now turn our attention to the relationship which, according to our theory, the masses of the celestial bodies should have in comparison to their distances from the sun, in order to test the results of our system against Newton's infallible calculations. It does not require many words to comprehend that the central body must always be the major part of its system. Consequently, the sun must be preponderantly greater than the planets collectively, just as the same point will hold for Jupiter and Saturn in relation to their nearby planets. The central body is created from the downward sinking from the entire extent of the sphere of its power of attraction of all particles incapable of attaining the most precisely established circular movement and a close relationship to the common plane. These must undoubtedly be a number uncommonly larger than those which attain orbital movement. To apply this observation in particular to the sun: if we wish to estimate the spatial extent in which orbiting particles which have served as basic material for the planets have deviated furthest from the common plane, then we can assume that it is, as an approximation, somewhat larger than the width of the greatest deviation of the planetary orbits from each other. Now, while they deviate from the common plane on both sides, their greatest angular difference with respect to each other is hardly 7.5 degrees. Thus, we can picture all the material out of which the planets were developed as having been distributed in the space which we imagine between two planes extending out from the sun at the centre and creating an angle of 7.5 degrees. However, a zone 7.5 degrees wide extending in the direction of the largest circle is a bit more than the seventeenth part of the spherical surface. Thus, the physical space between the two planes, which cut out a part of planetary space in the width of the above mentioned angle, is somewhat more than a 17th part of the physical contents of the entire sphere. Thus, according to this hypothesis, all material used for planetary development would comprise approximately the seventeenth part of the material which the sun assembled for its composition on both sides out as far as the furthermost planet is located. But this cluster of the central body has a preponderance over the combined content of all the planets which is not 17 to 1 but 650 to 1, as Newton's calculations have established. However, it is easy to see that in the higher regions beyond Saturn, where planetary development either ceases or is rare, where only a few comet bodies have arisen and especially where the movements of the basic material did not happen to acquire the equilibrium with the centripetal force as required by law (as in the regions closer to the centre) and ended up in an almost universal sinking toward the mid-point, it is easy, I say, to see that for these reasons the sun would have to acquire such a preponderantly large mass. However, in order to compare the planets with each other with respect to their masses, we first observe that, in accordance with the method of development, the quantity of material which combines in the composition of a planet depends particularly on the extent of its distance from the sun, for the following reasons: (1) Because of its power of attraction, the sun limits the sphere of the planet's power of attraction; however, for the same reason, the more distant planets are not so narrowly restricted as the close ones. (2) The circle from which all the particles have come together to make a more distant planet will be described with a larger radius and contain more basic material than the smaller circles. (3) For the reasons just mentioned, the width between the two planes of the greatest deviation at a constant angle is greater at a greater distance than at a small distance. On the other hand, this advantage for the more distant planets over the ones lower down will be limited by the fact that the particles nearer the sun will be of a denser type and, everything considered, will be less scattered than at a greater distance away. But we can easily conclude that for planetary development the first advantage is far greater than the limitation just mentioned. Generally the planets which develop a long way distant from the sun would have to acquire larger masses than the ones close to the sun. This happens in such a manner insofar as we imagine a planet's development with only the sun present. But if we admit the development of several planets at different distances, then one planet will restrict the extent of the power of attraction of another planet through the sphere of its own centripetal force. This brings about an exception to the previous principle. For the planet which is near another one of exception mass will lose a great deal from the sphere of its developmental material and thus will be much smaller than the relationship of its solar distance by itself requires. On the whole, the planets have a greater mass as they are further from the sun. Saturn and Jupiter, the two main parts of our system, are thus the biggest because they are furthest from the sun. However, deviations from this analogy do occur. But in them the mark of their common development is always manifest: the principle which we hold to, namely, that a planet of exceptional size deprives the nearest ones on both sides of the mass appropriate to them, given their distance from the sun. For it attracts to itself a portion of the material which should go into the development of both of them. In fact, because of its location, Mars should be bigger than the Earth. But Mars has a diminished mass because of the force of attraction from Jupiter, which is so large and close by. Although Saturn itself has an immediate advantage over Mars because of its distance, nevertheless Saturn has not been entirely free from suffering a considerable loss thanks to Jupiter's power of attraction. And it seems to me that Mercury owes its exceptionally small mass not only to the force of attraction of the powerful sun, which is so close by, but also to the fact that Venus is a neighbouring planet. If we compare the presumed density of Venus with its size, Venus must be a planet of considerable mass. Everything agrees as splendidly as we might wish in order to confirm the adequacy of a mechanical theory for the origin of the cosmic structure and the celestial bodies. Now, as we estimate the space in which the material stuff before the development of the planets was distributed, we wish to consider how diffuse the material was which filled this space and how free of obstacles the particles suspended all around were to established their rule-governed motions. If the space holding in itself all the planetary material was contained in that part sphere extending out to Saturn which was between two imaginary planes extending at an angle of 7.5 degrees to each other from the mid-point of the sun out into the full reaches of space (and which therefore comprised one seventeenth of the entire space which we can describe with a radius equal to the distance of Saturn), then in order to calculate the diffusion of the basic planetary material, we will set the distance of Saturn at 100,000 Earth diameters. Thus, the entire sphere of Saturn's orbit will exceed the volume of Earth by a factor of 1000 billion. If we take instead of the seventeenth part only the twentieth part of the space in which the elementary basic stuff was suspended, this must exceed the volume of Earth by a factor of 50 billion. Now, if, following Newton, we set the mass of all the planets along with their satellites at 1/650 of the mass of the cluster of the sun, then the Earth, which is only 1/169282 of this mass, will be related to the collective mass of all the planetary material in the ratio of 1 to 276.5. And if we then made all this material the same specific density as the Earth, we would produce a body which would take up a space 277.5 times greater than the Earth. Assuming that the density of the entire cluster of the Earth is not much greater than the density of the firm material which we encounter under Earth's outermost layer, as is required by the characteristics of the shape of the Earth, and assuming that this outer material is about 4 or 5 times denser than water and that water is 1000 time heavier than air, then, if all the planetary material is expanded to the density of air, it would take up a space almost 1,400,000 times larger than the Earth. This space is 30 million times smaller than the space in which, according to our theory, all the planetary material was spread out. Thus, the scattering of the planetary material in this space is much more thinly distributed than the particles of our atmosphere. In fact, the thin density of this scattered distribution, as inconceivable as it may appear, was neither unnecessary nor unnatural. It must be as thin as possible, in order to permit the suspended particles all freedom of movement, almost as in an empty space, and infinitely to reduce the resistance which they could have created for each other. They could, however, have assumed such a thinly distributed state on their own. We cannot doubt this point if we know a little about the diffusion which matter undergoes when it is transformed into vapour or when, to stay on the subject of the heavens, we consider the thinning out of the material in the tail of a comet, whose diameter, of an unheard of thickness, exceeds the diameter of the earth by a factor of a hundred and yet it is so transparent that the small stars can be seen through it, something which our air, when it is illuminated by the sun at a height many thousand times smaller, does not allow. I conclude this part by bringing out an analogy which in and of itself can raise the present theory of the mechanical development of the celestial bodies above a probable hypothesis to a formal certainty. If the sun is composed of particles of the same basic material from which the planets have developed and if the difference between them consists only in the fact that in the sun undifferentiated material of all sorts accumulated, while in the planets the density of their of their types was distributed according to the different distances, then if we consider the material of all the planets as a collective unity, from their complete intermixing the result would have to be a density almost equal to the density of the sun. Now, this necessary consequence of our system finds fortunate confirmation in the comparison which Buffon, that worthily celebrated philosopher, set out between the densities of the total aggregate of planetary material and the material of the sun. He found a similarity between the two in the ratio of 640 to 650. When unbiased and necessary consequences of a theoretical conception encounter such fortunate confirmation in true natural relationships, can we really then believe that mere contingency has effected this agreement between theory and observation? [Back to Top of Second Section] [Back to Table of Contents] Part Two Section Three Concerning the Eccentricity of the Planetary Orbits and the Origin of Comets We cannot make the comets a special class of celestial bodies entirely different from the family of planets. Here, as elsewhere, nature works by imperceptible stages. While it goes through all the series of changes, Nature links together distant qualities with ones close at hand, thanks to a chain of intermediate rungs. The eccentricity in the planets is the result of a lack of that impetus by which nature strives to make planetary movement precisely circular, something which, however, nature can never perfectly attain because of the intervening influence of various causes. However, the deviation from circular motion is greater at the larger distances from the sun than close by. This condition goes through a constant scale with all possible levels of eccentricity from the planets right up to the comets. True, this interconnection seems to be severed in the case of Saturn because of a large gap which completely separates the family of comets from the planets. But in the first part we have remarked that there probably are still other planets beyond Saturn which are more like comets because of a greater deviation from circularity in their orbital path and that it is only through a lack of observations (or also the difficulty involved in such observations) that this affinity was not long ago revealed as clearly to eye as to the understanding. In the first section of this part we have already referred to a cause which can render eccentric the orbit of a cosmic body developing out of the basic material suspended all around, even if we also assume that this body in all locations has forces moving it in a circular motion. Because the planet collects materials from location at a considerable distance from each other, where the orbital velocities are different, the materials collectively reach the planet with different degrees of inherent orbital velocity. These deviate from the velocity appropriate to the distance of the planet from the sun and thus induce an eccentricity for the planet insofar as these different impressed particulate motions fail fully to offset each other's deviation. If the eccentricity was caused only by this, it would be moderate everywhere. Also it would be less significant with the small planets far from the sun than with the closer and larger planets, if we assumed that the particles of the basic material had previously had a true circular movement. Now, these estimates do not agree with observation, since, as has already been mentioned, the eccentricity increases with the distance from the sun, and the small size of the masses appears much rather to create an exception to an increase in eccentricity, as we see with Mars. Thus, we are forced to limit the hypothesis about the precise circular movement of the particulate basic materials, so that, while they very nearly attain the determined precision in the regions near the sun, they nevertheless admit wider deviations from that precision the further the elementary particles are suspended from the sun. Such an adjustment of the basic principle of the free circular movement of the basic material is more naturally appropriate. For regardless of the spatial diffusion, which seems to leave them free to limit each other at the point of completely balanced equilibrium of the central forces, no less considerable are the causes which hinder the attainment of this natural goal. The further the dispersed parts of the basic material are from the sun, the weaker the force which induces them to sink down. The resistance of the particles below, which should force them to bend their fall sideways and to take up a direction perpendicular to the radius of the circle, is diminished in proportion as these particles sink downward either to disappear into the sun or to assume an orbit in a region closer to the sun. The fact that this more distant material has a much lighter specific gravity does not permit it to acquire the downward movement, which is the basis for everything, with the force necessary to brush the resisting particles aside. Perhaps these distant particles still restrict each other in order finally to overcome this uniformity after a long time. Thus, among these distant particles already small masses have developed as the starting point of many celestial bodies, which, because they are assembled from weakly moving material, sink toward the sun with only an eccentric movement and on the way are increasingly diverted from a perpendicular fall by taking on more quickly moving pieces. Finally, however, they remain comets if the spaces in which they have developed have through the sinking down toward the sun or through the assembling in particular clusters, become cleansed and empty. This is the reason why the eccentricity of the planets and those celestial bodies called comets increases with the distance from the sun. Comets have their name for the very reason that in this characteristic they far exceed the planets. There are indeed two exceptions which violate the law concerning the increase in eccentricity with the increasing distance from the sun. We see them in the two smallest planets of our system, Mars and Mercury. But with the first the cause is presumably the vicinity of the large planet Jupiter, which through its power of attraction on its side of Mars deprives it of particles and thus only allows Mars a special area in the direction of the sun in which to extend itself. This brings with it an excessive central force and eccentricity. So far as Mercury, the lowest but also the most eccentric planet, is concerned, it is easy to believe that, because the sun's axial rotation does not yet by a long way equal Mercury's velocity, the resistance which the sun presents to the material in the space surrounding it not only deprives the nearest particles of their central movement but also this resistance could easily extend right out to Mercury, whose projectile velocity would on this account have been considerably diminished. Eccentricity is the most significant mark of the comets. Their atmosphere and tail, which expand through the heat of their close approach to the sun, are only consequences of the eccentricity, although they have always served ignorance as uncommon images of horror, announcing to the common folk imaginary destinies. Astronomers, who pay more attention to the laws of motion than to the strangeness in the shape, notice a second characteristic distinguishing comets from planets, namely, unlike planets, comets do not confine themselves to the area of the zodiac, but establish their orbits in all celestial regions without restriction. This peculiarity has exactly the same cause as the eccentricity. The planets have confined their orbits to the narrow region of the zodiac because the elementary particles in the vicinity of the sun acquire circular movements which in each revolution have a tendency to intersect the interrelated plane and do not allow a body, once developed, to deviate from this plane towards which all the material from both sides presses. Thus, basic material from the spaces far from the mid-point which, because of the weak force of attraction, cannot attain free orbital movement for the very reason which produces eccentricity, is not capable of accumulating at this height on the plane interconnecting all planetary movement so as to maintain the bodies developed there on this particular path. Since it is not limited to a particular region, as is the case with the lower planets, the scattered basic material will far sooner develop on its own into celestial bodies equally easily on both sides by piling up far from the interconnecting plane or near to it. Therefore, comets will be fully free to descend toward us from all regions. However, those which first developed in a place not far above the planetary orbits will manifest less deviation from the limitations on their paths as well as less eccentricity. With the increasing distances from the mid point of the system, this lawless freedom of the comets in relation to their deviations increases and loses itself in the depths of the heavens in a total lack of orbital movement. This leaves the bodies developing in the outer regions free to fall toward the sun and establishes the last frontiers of the systematic arrangement. In this outline of the comet's movements, I propose that, so far as their orbital direction is concerned, for the most part they have one in common with the planets. It seems to me that in the case of the comets close by this is undoubtedly the case. Also this similarity of form cannot get lost in the depths of the heavens before the point where the elementary basic stuff in the least energetic state of motion establishes the rotation which arises in all directions from the downward sinking. For the time required in the commonality of the movements lower down to align them in a common direction is, on account of the large distance, too long for them to be able to extend themselves that far, while the development of nature goes on in the lower region. There will also perhaps be comets which will establish their orbits in the direction opposite to this principle, namely, from east to west. However, I might equally almost persuade myself, for reasons which I am reluctant to cite here, that of the nineteen comets in which we have observed this peculiarity, in some of them an optical illusion may have given rise to this observation. I must still note something about the masses of the comets and about the density of their material. For the reasons referred to in the previous section, according to the rules the development of these celestial bodies in the upper regions should proceed always according to the principle that, as the distance increases, their masses get larger. And we must also accept the fact that a few comets are larger than Saturn and Jupiter. But we do not have to hold that this quantity of the masses always increases in this manner. The scattering of the basic materials and the particular lightness of their particles make the development in the furthest region of cosmic space slow. The uncertain diffusion of this material in the entire infinite expanse of this space without any tendency to accumulate in the direction of any common plane initiates several small developments in place of a single considerable one. And the small centripetal force draws the largest portion of the particles down to the sun, without their having assembled themselves into masses. The specific density of the stuff out of which the comets develop is more worthy of attention than the size of the masses. Presumably since they are developed in the uppermost reaches of the cosmic structure, the particles which compose them are of the lightest sort. We cannot doubt that this is the major cause of the vapour sphere and the tail, which distinguish them from the other celestial bodies. We cannot attribute this dispersal of the comet's material in a vapour to the effect of solar heat. A few comets in their approach to the sun hardly reach the depth of the Earth. Many remain between the orbits of Earth and Venus and then turn back. If such a moderate level of heat dissolves and thins out the material on the surface of the comets to this extent, then they would have to consist of the lightest material which undergoes, under the influence of heat, more thinning out than any material whatsoever in all nature. Moreover, it is not possible to attribute the vapours which arise in such an accumulation from the comet to the heat which its body has left over from the earlier approaches to the sun. For indeed we must suppose that at the time of its development a comet has gone through several orbits with greater eccentricity and that these were reduced gradually. But the other planets, for which we could assume the very same, do not manifest this phenomenon. They would display it, if the varieties of the lightest material included in the composition of the planets had accumulated as much as they have with the comets. The Earth has something in itself which we can compare with the dispersal of the comet's vapours and their tails [i.e., the Northern Lights]. The finest particles which the effect of the sun draws from Earth's outer surface pile up around one of the poles, when the sun directs the semi-circle of its orbit into the opposite hemisphere. The finest and most energetic particles arising in the hot equatorial regions, having attained a certain atmospheric altitude, are compelled by the effect of the sun's rays to move away and accumulate in those regions which at that period are directed away from the sun and buried in a long night. These particles compensate the inhabitants of the icy regions for the absence of the great light, which also at this distance sends them the effects of its heat. Just this same power of the sun's rays, which creates the Northern Lights, would bring out a vapour circle with a tail, if the finest and most elusive particles on the Earth were in exactly the same accumulations as would occur on the comets. [Back to the Top of Third Section] [Back to Table of Contents] Part Two Section Four Concerning the Origin of Moons and the Axial Rotation of the Planets The striving of a planet to develop from the quantity of basic materials is at the same time the cause of its axial rotation and produces the moons which are to orbit around it. What the sun with its planets is on a large scale a planet with a sphere of attraction extending far out is on a small scale, namely, the major part of a system whose pieces have been set in motion through the force of attraction of the central body. Since the developing planet activates for its development the particles of the basic material from the total extent of its power of attraction, it will produce from all these sinking motions, thanks to their reciprocally interacting effects, circular movements. And these will finally settle upon a single common direction. Some of these motions will get moderated appropriately for free circular movement and in this limited area will be located close to a common plane. In this space, as with the main planets around the sun, the moons will develop around the planets, when the extent of the power of attraction of such cosmic bodies offers favorable conditions for their production. Furthermore, what was said in connection with the origin of the solar system can be applied equally well to the system of Jupiter and Saturn. The moons will arrange their orbital circles in one direction almost in a single plane. This will be set up for the same reasons as those in the large-scale analogy. But why do these satellites move in their common direction far more in the direction in which the planet moves than in any other? The moons' orbits are not produced through the circular movements of the planets. They acknowledge as cause only the power of attraction of the main planet, and, so far as this force is concerned, all directions are equally good. Mere contingency will select the direction out of all possible directions, according to which the sinking movement of the material changes into circles. In fact, the circular path of the main planet does nothing at all to impress upon the material out of which the moons are to develop orbital motion around it. All the particles around the planet move with it in the same motion around the sun and are, in relation to the planet, at rest. The power of attraction of the planet achieves everything by itself. But since all directions are in themselves equally suitable to the power of attraction, the orbital movement which arises out of that requires only a small external stimulus for the orbital movement of the moons to end up in one direction far more than in another. This small degree of steering the orbital movement acquires from the forward movement of the elementary particles which run simultaneously around the sun at a higher speed and in the sphere of the planet's power of attraction. For this requires the particles closer to the sun which orbit at a higher speed already from a considerable distance to abandon the direction of their path and to move up over the planet in an extended curve. Because these particles have a higher velocity than the planet itself, when they are drawn down by the planet's power of attraction, they produce in their perpendicular descent and also in the descent of the other particles a deviation from west to east. It requires only this slight steering to see to it that the orbital movement in which the descent, initiated by the power of attraction, finishes up takes on this direction far more than any other. Thus, all the moons will coordinate their orbital direction with the direction of the main planet's orbit. However, the plane of their path also cannot deviate far from the plane of the planetary orbits, because the material out of which they develop, for the very reason which we have referred to concerning orbital direction in general, is organized precisely in this way, namely coordinating itself with the plane of the principal orbits. From all this we clearly see what the circumstances are in which a planet may be able to acquire satellites. The power of attraction of the planet must be large and, as a result, the extent of the sphere in which this power is effective must extend far out, so that the particles moved to the planet through a long descent, without regard to the effects of resistance, at length are able to attain the velocity for a free orbital momentum. As well there must be present sufficient material for the development of moons in this region, something which cannot occur with a slight power of attraction. Thus, only planets with large masses and at a great distance from the sun are endowed with satellites. Jupiter and Saturn, the two largest and most distant planets have the most moons. Earth, much smaller than these planets, is assigned only one. And Mars, which on account of its distance might have merited some share of this advantage, goes without because its mass is so small. We observe with pleasure how the same force of attraction which brought the material for building moons and at the same time determined their movement extends to the very body of the planet itself in giving it an axial rotation (by means of exactly the same action through which the planet develops) in the common direction from west to east. The particles of the descending basic material, which, as mentioned, acquire a common rotational movement from west to east, fall for the most part onto the surface of the planet and are mixed into its cluster, because they do not have the appropriate velocity to maintain themselves in freely suspended orbital motion. Since they now come into collision with the planet, they must, as parts of it, continue just the same rotational movement and in exactly the same direction which they had before they were united with the planet. And it is easy to infer from the foregoing that generally the number of particles which the lack of necessary movement drives down to the central body must be very much greater than the number of those capable of attaining the appropriate level of