Chapter VIII: Part III (2)

It is, of course, true that the immediately prior condition of a sun or a planet was that of matter in an extremely attenuated or dissociated state. This is essential to the nebular, as well as to the meteoric, hypothesis. But it is not with the immediately prior condition that we are at present concerned, but with the primitive, or pre-nebular, condition. Take, for example, the case of the solar nebula, out of which our sun and planets were formed. Was this nebulous mass formed from matter in a state of extreme tenuity, scattered through space and collected together by gravity? Or did it result from two solid globes shattered to pieces by collision, which were then converted into the nebulous condition by the heat generated from the collision? It is no doubt true that the analogies of nature would, at first sight, be apt to lead us to the conclusion that the former theory was the more likely of the two, as the larger is generally made by aggregation from the smaller. But a little consideration will show that, in the present case, the weight of this analogy is more apparent than real. The impact theory does not rest upon a purely hypothetical basis. The cause to which it appeals has a real existence. The point of uncertainty is whether the cause actually produces the effect which is attributed to it. We know from observation that there are stellar masses, some of them probably larger than our sun, moving through space with enormous velocities in all directions.[77] According to the ordinary laws of chance, collision at times would be an inevitable result, and when such an event did take place the destruction of the colliding bodies, and their consequent transformation into a nebulous mass, would, at least in many cases, be a _necessary_ result. In fact, we have, in the case of these vast stellar masses, what we know occurs among the invisible molecules of a gas. So far as mere analogy is concerned, the impact theory is just about as probable as the other.

[Footnote 77: The dark stellar masses which escape observation may be as numerous as those that are visible.]

From what has been stated it would follow that in most cases the stellar masses have been formed out of the destruction of pre-existing masses, like the geological formations out of the destruction of prior formations.

_The theories do not account for the motion of the stars._—According to all the foregoing theories aggregation and condensation are produced by gravity. The materials dispersed throughout space are drawn together by their mutual attraction, and aggregated round a centre of gravity. Gravitation, although it imparts motion to the materials, can impart no motion of translation to the mass itself. Gravitation cannot, therefore, be the cause of the motion of translation of the mass. The stars are not supposed to be gravitating towards, or around, a great centre of attraction, for they are found moving in straight lines in all directions, which could not be the case if gravity were the cause of their motion. To what cause is their motion, therefore, to be attributed? A meteorite or other small body might be ejected from any system, by the explosive force of heat or some other cause, with a velocity which might carry it into boundless space; but such could not be the case in regard to a body of the magnitude of a star. No one for a moment could suppose that 1830 Groombridge, for example, moving at the rate of 200 miles a second, is an eject from any system.

According to the impact theory the whole is plain; for this 200 miles per second is simply a part of the untransformed motion of translation which the materials composing the star had from the beginning. In other words, the matter and the motion were eternal, or, what is more probable, as will afterwards be seen, co-existed from creation—not, however, as molecular motion, but as motion of the mass.

_The theories do not account for the amount of heat required._—It has been shown that, although the materials of our solar system had fallen together from an infinite distance, it could not have generated heat sufficient to have formed a gaseous nebula extending to the distance of the planet Neptune. Gravitation alone could not, therefore, have been the source from which the nebula obtained its heat. The solar nebula, however, must originally have extended far beyond the orbit of Neptune.

But supposing it could be demonstrated that the heat thus generated was sufficient to have formed a nebula extending to even twice the distance of Neptune, this would not remove the fatal objection to the gravitation theory of the origin of the solar nebula. For the facts, both of geology and of biology, equally show that the sun has been radiating his heat at the present rate for more than twice the length of time that it could possibly have done had gravitation been the source from which the energy was derived. This objection is alike fatal to the meteoric theory as it is to all other theories which attribute the origin and source of the heat to gravitation.

_Evolution of matter._—Our inquiries into stellar evolution do not, however, begin with the consideration of a gaseous nebula, or with swarms of meteorites. There was a pre-nebular evolution. The researches of Prout, Newlands, Mendelejeff, Meyer, Dumas, Clarke, Lockyer, Crookes, Brodie, Hunt, Graham, Deville, Berthelot, Stoney, Reynolds, Carnelley, Mills, and others, clearly show, I think, that the very matter forming this nebulous mass passed through a long anterior process of evolution. And not only the matter, but the very elements themselves constituting the matter, were evolved out of some prior condition of substance.

I have already given at some length the views which have been advanced by several of our leading physicists and chemists on the evolution of the chemical elements, and on some of the bearings which these views have on stellar evolution. I shall now briefly refer to a point on which I venture to think the theory discussed in this volume seems to cast some additional light.

If the elements were evolved out of a common source, there is, in order to this, one necessary condition, viz. an excessively high temperature; for the temperature must be above the point of the dissociation of all the chemical elements. “In the primal stage of the universe,” says Mr. Crookes, “before matter, as we now find it, was formed from the protyle, all was in an ultra-gaseous state, at a temperature inconceivably hotter than anything now existing in the visible universe; so high, indeed, that the chemical atoms could not yet have been formed, being still far above their dissociation point.”

What, then, produced this excessive temperature in this supposed ultra-gaseous protyle? It could not have resulted from condensation by gravity. In condensation the heat increases as the condensation proceeds, because it is the condensation which produces the heat. But here the reverse must have been the case, for the ultra-gaseous mass was much hotter than the sun which was afterwards formed out of it. It was, according to Mr. Crookes, when this gaseous mass cooled down, so as to permit of its becoming converted into solid matter, that condensation into a sun could take place. Besides, was it not the excessive heat which produced the assumed ultra-gaseous condition?

There is another difficulty besetting the theory that the primitive heat was derived from condensation by gravitation. Supposing we should assume it possible that the protyle could exist in this ultra-gaseous state without possessing temperature, and that it obtained its heat from condensation by gravity, then the fact of condensation taking place shows that the gas was not in a state of equilibrium. But the gas could not have remained stationary for a single moment without beginning to condense while in a condition of unstable equilibrium. We must therefore conclude that the gas must have been in some other condition than the gaseous state prior to condensation.

The impact theory seems to remove all these difficulties. It is just as likely _à priori_, if not more so, that the primitive form of the protyle should have been that of large cold masses moving through space in all directions, with excessive velocities, as that it should have been that of a gaseous mass in a state of unstable equilibrium. If we assume the former condition, then the colliding of these masses would account not only for the ultra-gaseous state, but also for its inconceivably high temperature. Besides, in this case we are not called upon to account for any other antecedent state of the masses before collision, for they may have existed from the beginning of creation in the form of masses in motion through space.

Had space and time permitted, it might have been shown that there are other obscure points on which the theory seems to shed additional light. I shall now, in conclusion, refer to a point wherein the theory differs radically from that of all other theories of stellar evolution. But before doing so I may briefly refer to an objection which has been frequently urged against the theory.

_Objection considered._—The objection to which I refer is this, that, had the nebulæ been produced by impact in the way implied in the theory, then we ought to have had some historical record of such an event. I can perceive no force in such an objection. Our historical records, I presume, do not extend much farther back than about 3,000 years, and we have no evidence to conclude that a new nebula makes its appearance in the visible firmament with such frequency; and supposing it did, we have no grounds for assuming that its production by impact in the way supposed by the theory would attract general notice. It is doubtful if the nebula produced would, in the first instance, be actually visible. I have shown that the temperature of the nebula could not have been less than about 300,000,000° C., and it is very doubtful if the gaseous mass enveloping all that was solid in the nebula would, at such a temperature, be self-luminous. The probability is that all the chemical elements composing it would be in a state of utter dissociation, and converted back into the original protyle from which they were derived, again to be slowly reconverted into their former atomic condition as the temperature fell.

_Can we on scientific grounds trace back the evolution of the universe to an absolute first condition?_—As has been repeatedly stated, all inquiries into the evolutionary history of the stellar universe begin in the middle of a process. Evolution is a process. The changes that now occur arose out of preceding changes, and these, preceding changes out of changes still prior, and so on indefinitely back into the unknown past. This chain of causation—this succession of change—of consequent and antecedent—could not in this manner have extended back to infinity, or else the present stage of the universe’s evolution ought to have been reached infinite ages ago. The evolution of things must therefore have had a beginning in time. Professor Winchell, in his final generalisation to his work, “World Life,” has stated this matter so clearly and forcibly that I cannot do better than here quote his words on the subject.

“We have not,” says Professor Winchell, “the slightest scientific grounds for assuming that matter existed in a certain condition from all eternity, and only began undergoing its changes a few millions or billions of years ago. The essential activity of the powers ascribed to it forbids the thought. For all that we know—and, indeed, as the _conclusion_ from all that we know—primal matter began its progressive changes on the morning of its existence. As, therefore, the series of changes is demonstrably finite, the lifetime of matter itself is necessarily finite. There is no real refuge from this conclusion; for, if we suppose the beginning of the present cycle to have been only a restitution of an older order effected by the operations of natural causes, and suppose—what science is unable to comprehend—that older order to be a similar re-inauguration, and so on indefinitely through the past, we only postpone the predication of an absolute beginning, since, by all the admissions of modern scientific philosophy, it is a necessity of nature to run down.”

These are consequences which necessarily follow from every theory of stellar evolution which has hitherto been advanced. The impact theory, however, completely removes the difficulty, for according to it the evolutionary process can, on purely scientific grounds, be traced back to an absolute beginning in time. If huge solid masses moving through space were the original condition of the universe, then, in so far as either philosophy or science can demonstrate to the contrary, it might have been in this condition from all eternity. We are therefore not called upon to account for this primitive condition of things. Now it is evident, unless a collision should take place, the universe would remain in this condition for ever: without a collision there could be no change, no work performed, and absolutely no loss or gain of energy, and therefore no process of evolution. The first collision would be the absolute commencement of evolution—the beginning of the process of the development of the universe. Evolution would, in this case, have its absolute beginning in time, and consequently was not eternal. If, on the other hand, we assume, what is far more in harmony with physics, metaphysics, and common sense, that the universe was created in time, we are still led to the same result as to an absolute commencement of evolution. In both cases we reach a point beyond which there can be no legitimate inquiry; no further question which the scientists can reasonably ask.

We have no grounds to conclude that there is anything eternal, except God, Time, and Space. But if time and space be subjective, as Kant supposes, and not modes pertaining to the existence of things in themselves, then God alone was uncreated, and _of_ Him and _to_ Him are all things.

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INDEX.

Aqui Range, Utah, fault in, 57

Arcturus, motion of, 16

Atmosphere, universal, 82

„ Dr. Hunt on, 86

„ Mr. Mattieu Williams on, 86

Atomic weights, logarithmic law of, 100

Atoms, according to Herschel and Clerk-Maxwell, manufactured articles,
92

Binary systems, 32

„ Dr. Johnstone Stoney on, 33

„ Sir W. Thomson on, 33

Biology, testimony of, as to age of sun’s heat, 65

Brodie, Sir B., on the pre-nebular condition of matter, 84

Brown and Dickson on sediment of the Mississippi, 40

Carnelley, Dr., argument from compound radicals, 94

μ Cassiopeiæ, motion of, 16

α Centauri, distance of, 16

Chemical elements, evolution of, 80

Clarke, Prof. F. W., on atomic weights, 93

„ on evolution of the chemical elements, 80, 89

„ on the pre-nebular condition of matter, 98

Comets, according to Laplace, strangers to our system, 17

„ according to Prof. A. Winchell, strangers to our system, 17

„ M. Faye on origin of, 17

„ probable origin of, 17

Compound radicals, argument from, 95

Condensation in relation to nebulæ, 27

„ the last condition of a nebula, 30

Cosmical dust and “fire-mist,” 81, 102

Crookes, Mr. W., on the pre-nebular condition of matter, 90-98

„ on _protyle_, 96

61 Cygni, motion of, 16

Darwin, Mr. Charles, on geological time, 67

Denudation, age of the globe as represented by, 63, 64

„ average rate of whole globe, 44

„ evidence from faults as to rate of, 53

„ Dr. A. Geikie on rate of, 41

„ glacial epochs in relation to, 46, 47

„ in Colorado, 58

„ in past ages not much greater than at present, 44

„ method employed to estimate its rate, 39, 47

„ Mr. A. R. Wallace’s method of estimating its rate, 51

„ of Bristol coal-fields, 59

„ of Mississippi basin, Sir Charles Lyell on, 44

„ of Pendle Range, 60

„ of Pentlands, 59

„ of river basins, 41

„ of South of Scotland, 55

„ of Wales, 59

„ Prof. Haughton’s method of estimating its rate, 50

„ Rotation of the earth in relation to, 46

„ the direct method of estimating its rate, 52

„ time required to effect the amount of, 63

Dewar and Liveing on dissociation of chemical elements, 83

Dissociation of chemical elements, Dr. T. Sterry Hunt on, 82, 85

„ of chemical elements, M. Berthelot on, 83

„ of chemical elements, M. Deville on, 83

„ of chemical elements, Mr. Lockyer on, 82

„ of chemical elements, Profs. Liveing and Dewar on, 83

„ of chemical elements, Prof. Schuster on, 83

„ of chemical elements, Sir B. Brodie on, 82, 84

„ Dumas, M., on essential unity of matter, 83

Earth’s crust, argument from, 93

„ rotation, its influence on denudation, 46

Emmons, Mr. S. F., on a fault in Aqui Range, 58

Energy existing as motion of stellar masses, 3

„ transformed by collision, 3

Evolution, can it be traced back to a first condition? 110

„ evidence of, from the grouping of the stars, 81

„ from smaller to larger aggregates of matter, 81

„ of matter, 107

„ of the chemical elements, 80, 107

Faults, evidence of rate of denudation from, 53

„ examples of, 54-60

„ “Grand Wash,” Colorado, 58

„ in East Tennessee, 58

„ in Strathmore, 55

Faye, M., on origin of comets, 17

Gaseous condition essential to the nebular hypothesis, 25

„ state, second condition of a nebula, 24

Geikie, Dr. A., on area of the globe, 48

„ on denudation of the Pentlands, 59

„ on examples of enormous faults, 55

„ on rate of denudation, 41

Geological epochs of past ages, misconceptions regarding, 49

Geological time, Mr. A. R. Wallace on, 65

„ time, Mr. Charles Darwin on, 66

„ time, Prof. Haeckel on, 67

„ time, Prof. Huxley on, 65, 66

„ time, Sir Andrew C. Ramsay on, 67

Geology, testimony of, in regard to age of sun’s heat, 39

Glacial epoch, age of the earth as determined by, 64

„ epochs, influence on denudation, 46

Gravitation does not account for the heat required, 106

„ does not account for motion of the stars, 105

„ insufficient to account for heat of nebulæ, 27

Groombridge 1830, motion of, 15

„ not an eject, 106

„ Prof. Newcomb on motion of, 15

Grove, Sir W. R., on the pre-nebular condition of matter, 78

Haeckel, Prof, on geological time, 67

Haughton, Prof., method of estimating rate of denudation, 50

Heat, age of the sun’s, 37

Helmholtz on age of sun’s heat, 35

Huggins, Mr., and Dr. Miller on spectra of nebulæ with one nitrogen
line, 84

Hull, Prof., on denudation of Pendle Range, 60

„ on examples of enormous faults, 54

Humphreys and Abbot on sediment of the Mississippi, 40

Hunt, Dr. T., on the pre-nebular condition of matter, 85

„ on universal atmosphere, 86

Huxley, Prof., on geological time, 65, 66

Hypothesis, value of, 70

“Impact Theory,” why so called, 2

„ in relation to theories of pre-nebular condition of matter, 102

„ removes difficulties regarding origin of heat, 108, 109

ε Indi, motion of, 16

King, Mr. Clarence, on the Wahsatch Fault, 59

Lalande 21185, motion of, 16

„ 21258, motion of, 16

Laplace, M., on the heat of the solar nebula, 30

Lavoisier, M., on simpler forms of matter, 86

Lesley, Mr. J. P., on a fault in the Appalachians, 57

„ on fault in East Tennessee, 58

Liveing and Dewar on dissociation of chemical elements, 83

Lockyer, Mr., on arrangement of the planets according to density, 25

„ nebulæ with solid matter in a gaseous mass, 20

Lockyer, Mr., on essential condition of solar nebulæ, 25

„ on hypothesis, 70

„ on number of meteorites, 103

„ on outburst of stars, 33

„ on “sorting” of the chemical elements, 25

Lodge, Prof. O., on ethereal origin of matter, 87

„ on the pre-nebular condition of matter, 87

„ on vortex atoms, 88

Logarithmic law of atomic weights, 100

Lyell, Sir Charles, on denudation of the Mississippi basin, 44

Macvicar, Dr., on ethereal origin of matter, 87

Matter not probably eternal, 112

Mendelejeff, Prof., on Periodic Law, 96

Meteorites, number greatly exaggerated, 103

„ probable origin of, 12

„ Sir H. Roscoe on constitution of, 12

„ Sir W. Thomson on, 12

Mill, Mr. J. S., on hypothesis, 70

Miller, Dr., and Mr. Huggins on spectra of nebulæ with one nitrogen
line, 84

Mills, Dr., on Polymerisation, 95

Morris, Mr. Charles, on the pre-nebular condition of matter, 75

Nebulæ, broken fragments in a gaseous mass, 19

„ cometic, 22

„ condensation insufficient to account for heat of, 27

Nebulæ condensation, last condition of, 30

„ first condition of, 19

„ gaseous state, second condition of, 24

„ „ globular, 21

„ heat of, not due to gravitation, 27

„ how they occupy so much space, 18

„ how origin of by impact might not have been observed, 110

„ must possess an excessive temperature, 26

„ Mr. Lockyer on, 20-22

„ origin of, 18

„ Prof. A. Winchell on meteoric origin of, 22

„ Prof. Tait on, 20

„ Sir W. Thomson on origin of, 6, 28

„ spheroidal, 22

„ why of such various shapes, 19

Nebular hypothesis, gaseous condition essential to, 2, 5

Newcomb, Prof., on motion of 1830 Groombridge, 15

Newlands on Periodic Law, 96

Nova Cygni, on sudden outburst of, 33

Objection considered, 109

Palæozoic times, winds probably not higher than at present, 46

Peach, Mr. B. N., on examples of enormous faults, 55

„ on denudation of the south of Scotland, 55

Periodic Law, argument from, 96

„ Prof. Mendelejeff on 96

Periodic Law, Newlands on, 96

„ Prof. Reynolds on, 96

Planets, on their arrangement according to density, 25

Polymerisation, argument from, 95

„ Dr. Mills on, 95

Pouillet, on rate of solar radiation, 2, 35

Powell, Major J. W., on denudation of Uinta Mountains, 58

Pre-nebular condition of matter, Dr. G. Johnstone Stoney on, 99

„ condition of matter, Dr. T. Sterry Hunt on, 85

„ condition of matter, Mr. Charles Morris on, 75

„ condition of matter, Mr. W. Crookes on, 90

„ condition of matter, Prof. A. Winchell on, 71

„ condition of matter, Prof. F. W. Clarke on, 98

„ condition of matter, Prof. Lodge on, 87

„ condition of matter, Sir B. Brodie on, 84

„ condition of matter, Sir W. R. Grove on, 78

„ evolution, 107

Proctor, R. A., on meteoric origin of solar system, 23

_Protyle_, the primal matter, 96

Prout’s Law, argument from, 92

Ramsay, Sir Andrew C, on denudation of Bristol coal-fields, 59

„ on denudation of Wales, 59

„ on geological time, 67

Reynolds, Prof., on Periodic Law 96

Rogers, Prof. H. D., on a great fault in the Appalachian coal-fields,
57

Roscoe, Sir H., on constitution of meteorites, 12

Rotation, supposed influence on denudation, 46

Saigey, M., on ethereal origin of matter, 87

Schmidt, Dr., on number of meteorites, 103

Solar nebula, M. Laplace on heat of, 30

„ Mr. Lockyer on condition essential to, 25

„ Sir W. Thomson on, 6, 28

Solar radiation, rate of, according to Pouillet and Langley, 35

Solar system, Mr. R. A. Proctor on meteoric origin of, 23

Star clusters, 34

Stars, evidence of evolution from their grouping, 81

„ how origin of by impact might not have been observed, 110

„ in four groups, 81

„ motion not accounted for by gravitation, 105

„ motion not due to their mutual attractions, 14

„ motion of, how in straight lines, 14

„ sudden outbursts of, 33

Stoney, Dr. G. Johnstone, on the pre-nebular condition of matter, 99

Subaërial denudation, method of estimating rate of, 39, 47

Sun, age of heat of, 34

Sun’s heat, age of, according to Geology, 37

„ age of, a crucial test, 34, 37

Sun’s heat, age of, according to Thomson and Tait, 35

„ age of, as determined by Biology, 64

„ age of, as determined by Geology, 39

Tait, Prof., nebulæ with solid matter in a gaseous mass, 20

„ on age of sun’s heat, 35

Temperature excessive, essential to nebulæ, 26

„ produced by collision, 5

Thomson, Sir W., on age of sun’s heat, 35

„ on meteorites, 12

„ on origin of solar nebula, 28

„ on solar nebula, 6

„ suggestion by, 86

Tides, supposed influence on denudation, 45

Tycho Brahe, on sudden outburst of a star, 33

Tylor, Alfred, on the denudation of Mississippi Basin, 40

Uinta Mountains, denudation of, 58

„ fault in, 57

Vortex atoms, Prof. Lodge on, 88

“Wahsatch Fault,” Utah, immense dislocation, 58

Wallace, Mr. A. R., on geological time, 65, 68

„ method of estimating rate of denudation, 57

Williams, Mr. Mattieu, on universal atmosphere, 86

Winchell, Prof. A., on age of the earth, 64

„ on comets strangers to our system, 17

„ on denudation of Colorado plateau, 58

„ on deposition of Palæozoic sediment, 45

„ on ethereal medium, 87

„ on meteoric origin of nebulæ, 22

„ on nebular hypothesis, 69

„ on the pre-nebular condition of matter, 71

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Transcriber’s note:

Front matter, ‘By’ changed from small caps to letter case, “By JAMES CROLL, LL.D., F.R.S. With”

Page 2, comma inserted after ‘Mag.,’ “Phil. Mag., July 1878;”

Page 25, full stop inserted after ‘Lectures,’ “Manchester Science Lectures.”

Page 37, heading ‘Testimony...’ changed to small caps.

Page 41, ‘years’ inserted, “Mean 3,378 years”

Page 54, full stop inserted after ‘Mem.,’ “Mem. Geol. Survey of Lancashire”

Page 59, full stop inserted after ‘vol. i.,’ “Memoirs of Geol. Survey, vol. i.”

Page 113, ‘radicles’ changed to ‘radicals,’ “argument from compound radicals”

Page 115, ditto inserted, “„ on examples of enormous faults”

Page 116, ditto inserted, “„ globular”

Page 117, page entries reversed, “of solar radiation, 2, 35”

Page 117, ‘geologica’ changed to ‘geological,’ “on geological time”

Page 118, ditto inserted, “„ fault in, 57”