Robert Stawell Ball

“ Were a pair of gigantic weighing scales constructed, and Jupiter placed in one of these scales, then it would require 300 globes each as heavy as the earth to be placed in the other before the mighty balance could turn. Yet when we remember that Jupiter is 1,200 times as large as the earth we may well feel surprised at learning that he is only 300 times as heavy. Were the constitution of the planet at all like that of our earth, then the weights and the sizes should observe the same proportions, just as one solid iron ball, when ten times as big as another, will be ten times as heavy. ”

“ In many of the planets we can see little or nothing of this kind that can be certainly made out, while even on those which we can see best it is only the very broadest and most striking features that can be discerned. Of Venus, unhappily, we can see nothing or next to nothing that would give us any information as to the presence or the absence of oceans and clouds. The loveliness of the evening star is due to the brilliancy of the sun-beams in which she is decked, but this very brilliancy is inconvenient in the telescope, where it merely appears as a glare which renders all details invisible. ”

“ Imagine a great sphere to be described with its centre at our earth, and with a radius extending all the way from the earth to this last star knowable by man. Every star that we can see, every star whose existence becomes disclosed to us on our photographs, lies inside this sphere; as to the orbs which may lie outside that sphere we can know nothing by direct observation. ”

“ From one cause or another, it happens that Mars is the most world-like of all the other globes which come within the range of effective observation. It would, indeed, be very rash to assert that other bodies may not have a closer resemblance to our earth than Mars has, but of them we have either little knowledge, as in the case of Venus, or no knowledge at all. No doubt both Jupiter and Saturn can vie with Mars in the copiousness of detail with which they delight the astronomers who study them. ”

“ There is the iron in the ore; there are the great stores of pig-iron lying ready for use; there are the vast bridges which span our rivers and straits; there are the thousands of miles of railway lines; there are the countless wheels and pieces of machinery; there are iron vessels on every ocean, and objects of every size made of iron, from the smallest nails up to hundred-ton guns. There is also at this moment, and every moment, a good deal of hot iron on the earth. ”

“ If the sun shall ever cease to shine, then must it be certain that there is a term beyond which human existence, or indeed, organic existence of any type whatever, cannot any longer endure on the earth.
We may say once for all that the sun contains just a certain number of units of heat actual or potential, and that he is at the present moment shedding that heat around with the most appalling extravagance. No doubt the heat-hoard of the sun is so tremendous that the consequences of his mighty profusion do not become speedily apparent. ”

“ How comes it that people are talking about and thinking about Jupiter's fifth satellite, while there are thousands or rather millions of stars lying unnoticed through space? and yet any one of these stars is perhaps a million times as big as this little satellite, besides being a sun, which may presumably be a source of light and heat to planets which circulate around it. What is the ground for so much excitement about the discovery of an object which is probably among the most minute, if not itself actually the most minute, of all the objects of which our telescopes can take cognisance? ”

“ Each of these little particles, no matter how quiet the air as a whole may seem, is in a state of intensely rapid movement. Picture to yourself incalculable myriads of little objects, each dashing about with a speed as great as that of a rifle bullet, and often indeed far greater. The little particles are so minute that it would take about fifty millions of them, placed side by side, to extend over a single inch. The smallest object which we can discern with a microscope is perhaps one hundred-thousandth of an inch in length. ”

“ To take one instance, we may mention that if the sun had been a globe of white-hot carbon, and if there had been a sufficient supply of oxygen to effect its combustion, the total heat generated by the entire mass would not supply the solar radiation for the period that has elapsed since the building of the pyramids. It is, therefore, clear that the supposition that the sun is a burning globe, like the supposition of the sun as a cooling solid globe, is quite inadequate to explain the marvellous persistence with which, for countless ages, the orb of day has distributed its beams. ”

“ I have shown the extreme unlikelihood that any missile discharged from a volcano, on a globe lying somewhere in the stellar distances, could ever reach this earth. I have shown this improbability to be so great, that even though there might be hundreds of millions of presumable globes throughout space, we cannot entertain the supposition that any missile starting from one of them could ever fall down here. I have shown that meteorites cannot be reasonably associated with comets, notwithstanding the undoubted alliance which exists between comets and shooting-stars. ”

“ When we reflect that this expenditure of heat has been going on not alone for the centuries during which the earth has been the abode of man, but also for those periods which we cannot estimate, except by saying that they are doubtless millions of years, during which there has been life on the globe, then indeed we begin to comprehend how vast must have been the capital of heat with which the sun started on its career. ”

“ IS THE UNIVERSE INFINITE?
ISHOP BUTLER has well remarked that "probability is the guide of life," and, assuredly, if it be our guide in all practical concerns, in a still more significant sense may it be claimed as the source of the greater part of human knowledge. Indeed, in a rapid survey of the field of astronomy we are tempted to affirm, not merely that the theory of probability is of the utmost service to us, but that it is almost our sole method of discovering the truth. ”

“ We cannot, however, attribute to the sun any miraculous power of generating heat. That great body cannot disobey those laws which we have learned from experiments in our laboratories. Of course no one now doubts that the great law of the conservation of energy holds good. We do not in the least believe that because the sun's heat is radiated away in such profusion that it is therefore entirely lost. It travels off no doubt to the depths of space, and as to what may become of it there we have no information. Everything we know points to the law that energy is as indestructible as matter itself. ”

“ Mars happens to be the more interesting globe to us simply because it is better placed for observing. Everybody knows that you can read your book comfortably if you sit with the light so nearly behind you that it may fall on the page at which you are looking. This is the aspect in which Mars is presented at opposition. The sun, which illuminates Mars, is then at midnight, behind the observer, but its beams are directed full on the planet, and exhibit it under the most favourable conditions. But Venus is presented to us in quite a different manner. ”

“ No doubt the theory of probabilities has nothing to say against Alcyone in comparison with any other star visible in the heavens, but what it does say is that it would be utterly preposterous to imagine that any one of the stars in the visible firmament could be the central sun around which all the bodies in the universe revolved. For summon up to your imagination the most distant star that can be seen with the unaided eye. ”

“ There seems to be no doubt that some of the nebulæ are quite as near to us as some of the stars. At all events, for our present purpose, we may group the Milky Way, the nebulæ, the stars, and the clusters, all into one whole which we call our sidereal system. Is this sidereal system as thus defined an isolated object in space? Are its members all so bound together by the law of universal gravitation that each body, whatever be its movements, can only describe a certain path such that it can never depart finally from the system? ”

“ A so-called "water-gas" may no doubt be used for developing heat, but it is not the water which supplies the energy. Trains may be run by electricity, but all that the electricity does is to convey the energy from the point where it is generated to the train which is in motion. Electricity is itself no more a source of power than is the rope with which a horse drags a boat along the canal. There is much more philosophy in the old saying, "Money makes the mare to go," than in the optimistic doctrine we often hear spoken of with regard to the capacity of man for dealing with nature. ”

“ Then as the spring drew near, if, indeed, such a word as spring be at all applicable to an abode of utter dreariness, a faint twilight would be just discernible. The illuminated portion of the sky would move round and round the horizon each twenty-four hours, gradually becoming more and more conspicuous, until at last the edge of the sun appeared. ”

“ The mighty sphere can only be an infinitely small part of space. Are we then entitled to assert that every particle in the universe attracts every other particle with a force which is proportional to the product of their masses, and which varies inversely as the square of their distance? We have, indeed, but a slender basis of fact on which to rest a proposition so universal. Let us attempt to enunciate the law of gravitation so as to commit ourselves to no assertion not absolutely proved. ”

“ No astronomer ever seriously entertained the notion that there was such a system of attendants revolving around Jupiter until their existence had been demonstrated once and for all by the telescope of Galileo.
There can be no doubt that the moons of Jupiter are in themselves quite bright enough to be ordinarily seen by the unaided eye were it not for a single circumstance. They lie too close to the great planet. At first sight it might seem that the very fact that they are placed in the brilliant illumination which Jupiter radiates should rather tend to make them more easily discerned. ”

“ The larger the body the more abundant the atmosphere by which that body is surrounded. Of course this rule has to be understood with certain qualifications, and perhaps some exceptions to it might be suggested, but as a broad general fact it will hardly be questioned. Thus, to take at once the largest body of our system and one of the smallest—the sun and the moon—they both provide striking exemplifications of the principle in question. It is well known that the sun is enveloped by an atmosphere remarkable for the prodigious extent that it occupies. ”

“ There is no means of replenishing to any large extent the heat of the inside of our earth by combustion. The earth's interior temperature must, therefore, on the whole, be simply falling in accordance with the laws of cooling.
The conclusion to which we are led by this reasoning is a remarkable one. We know that our earth has been in existence for an incalculable period of time. We are not even able to estimate how many thousands of years have elapsed since man began his course on our globe, but the human period is merely the latest of all the great periods in world-history. ”