Charles B. Warring

“ In the sky it appears so small that we find it difficult to realize that scarcely more than 100 times its diameter would reach so far.
However many of us may have sought, by these or by other illustrations, to form some conception of the vastness of the universe, but few have attempted to grasp the measure of that power which compels the planets to move in elliptical orbits instead of flying off in tangents, as, if left to themselves, they would inevitably do; and still fewer have thought of the force with which these bodies tend to pull one another out of their courses. ”

“ It is difficult to believe that so small a body exerts any considerable influence on the earth which seems so immensely larger. It is easy enough to admit that the earth holds the moon in its orbit; but, that to do this, to bend its course into a nearly circular orbit, requires any great outlay of force, is not so clear. Our credulity would be taxed were we asked to believe that the moon in its efforts to move in a straight line would break away, although held by a bar of steel one foot square, for that means a force able to lift nearly 9,000 tons. ”

“ If our earth were struck out of existence, it would hardly be missed from such a system. But this is far from the extreme measure of our littleness. The evening sky is studded with stars. Between us and them is empty space. As we look across it, the distance does not seem so very great, and even astronomers were long in learning how great it is, and how utterly isolated the sun with its train of planets is from even the nearest star. ”

“ The earth is 81 times the mass of the moon; the sun is 315,000 times the mass of the earth, and something more than 381 times as far from it as we are from the moon. Combining these in an easy calculation, we find that the sun puts forth upon our earth a coercive force to bend its path into an ellipse, a force to be measured by 15,000,000 of our unit-bars, together making a bar of solid steel whose section would cover 15,000,000 square miles, more than four times the area of the United States. ”

“ If a web of steel were stretched from the earth to the moon to hold our satellite from flying off into space, each tiny thread being represented by a bar of steel one fourth of an inch square no trifle, for each could hold 7,500 pounds—they would cover our globe on the side toward the moon with a network whose threads would be only six inches apart, and through which none but the smallest animals could pass. ”

“ The force which thus impels our sun reacts on other suns, and they on each other, and thus all are in movement. This is not a conclusion drawn from mere theorizing; the measurements of astronomers have established the fact that the "fixed" stars are moving with enormous velocities, not, as has often been said, about a common center, but in directions which cross each other at all angles. Millions of years hence these movements will result in the destruction of the present universe, unless He who called the stars into existence shall lay his hand upon them. ”

“ When we remember that each star, however remote, adds its quota of force, and that a star whose light requires 6,000 years to reach the earth is linked to our system by a band able to lift more than 14,000,000 tons, we may well believe that our system is being hurried through space in a path which is the resultant of innumerable forces. ”

“ From each star reaches out to our sun a force, small as compared with those which hold our system together, yet of a size that will amaze us. To the nearest of these far-off suns the distance is so great that light, which travels almost 200,000 miles in a second, requires three years to traverse it! ”

“ Yet that sun, which in this estimate we have mentally reduced to a point 1100 of an inch in diameter, is in reality a body so vast that, were it hollow, and our earth placed at its center, the moon would not only revolve freely around our planet, just as it now does, but on every side the sun would extend more than 200,000 miles beyond the lunar orbit. ”

“ We must work out our conclusions ourselves. The data are all at our hand. We need only to know the distances and masses; the rest is a matter of easy computation. But that our results may not be meaningless from their very greatness, it will be wise to follow the method which we pursue when trying to get an idea of great distances. We take first some unit with which we are familiar—for instance, a mile—and think how many miles it is to some place familiar to us. ”

“ Such a distance reduces proportionably the attraction; yet our sun with its attendant planets is drawn by mutual attraction toward the nearest star, supposing them to be of the same size, with a force great enough to break a cable, each of whose strands, 236 in number, should be a solid bar of steel one mile square; or, if we change our scale, and employ such bars as those used when speaking of the interplanetary forces, bars of steel one foot square, then the attraction between the nearest tiny speck of light and our sun would be equal to the united strength of 6,500,000,000 such bars. ”

“ This bar is to be the unit of measure which I shall for the present employ, and with its help I shall attempt to give some idea of the influence of the sun in holding the system together, and of the attraction exerted by the planets upon our earth, and by the earth upon the moon; and, lastly, by the fixed stars upon the sun and upon each other.
We begin with the moon because it is nearest to us, and, with the exception of the sun, is to us the most important of all the heavenly bodies. ”

“ We have heard so often of the distance from here to the sun, 921⁄3 millions of miles, that we begin to think we have some idea of its inconceivable greatness. Yet, so large is the sun that only 107 such bodies, laid so as to touch each other, would be needed to form a continuous bridge from the earth to that luminary. ”

“ Mars pulls enough to overcome the united strength of 590,680,000; while Jupiter draws away with a steady tug of nearly 23,000,000,000; and even Neptune, 2,700,000,000 miles away, and utterly invisible to the naked eye, still has sufficient energy to drag our earth toward it with force able to snap 27,000,000 such bars. ”

“ Philosophers have found that a steel wire one tenth of an inch in diameter will support nearly half a ton, while a bar one inch square will not be pulled asunder by less than sixty tons. If two inches square, it will require 240 tons; if three inches square, it will scarcely break with 540 tons. Bars of steel are not often made larger than this, although Krupp, in his colossal works, doubtless makes some whose section equals 144 square inches. To pull apart such a bar would require a strain equal to the weight of 8,640 tons. ”

“ Mercury, which is too small and too near the sun for most of us to have seen, draws the earth when in mean perigee with a force small indeed when compared with those which we have been considering, but large enough to break 232,390,000 bars one foot square ”

“ Then we extend that measure, or some multiple of it, to another place more remote, and then to one still more distant; and thus by degrees we become able to grasp distances whose statement in figures had previously conveyed little or no meaning to our minds. So, in measuring a force, we get a better idea of its greatness if we work up to it in a similar manner. ”

“ But still, distant as it is, Jupiter's immense mass demands incomparably the strongest measures to keep it in check; nothing less than 170,000,000 of those bands of steel will overcome its wandering tendencies. Saturn, being a lighter weight, is more easily guided—15,000,000 suffice for that. ”

“ The earth would be only 11000 of an inch in diameter, requiring 1,000,000,000,000 times its bulk to make a globe one inch in diameter. On such a scale our world would be equaled in minuteness only by the animalcules which the microscope reveals. ”

“ Of all known substances steel is the most tenacious. If the interplanetary forces can be represented by steel bars of known size, it will at least help to bring them within the limits of our comprehension. ”

“ Keeping the same scale as before, in which our inconceivable distance from the sun, 9213 millions of miles, was reduced to a dozen rods or so, and then setting out to visit our neighbors, if we are lucky enough to turn our steps to the nearest, we find before us a journey of nearly 9,000 miles. ”

“ If, now, we turn to the planets, and study their influence, we shall find them pulling and tugging at each other with forces that, but for compensations planted in the system itself, would tear it to pieces ”

“ Endeavor to get some idea of its tenacity, and how many million horses it would require to pull it asunder, and then, after getting somewhat accustomed to the greatness and strength of a bar of solid steel 1612 feet square, imagine one which is one mile square—5,280 feet wide, and as many thick. ”

“ Of these influences astronomers have given no illustrations, yet their contemplation will lead to results that will enlarge our views of the universe, and help us to rise at least a little toward a conception of Omnipotence. ”

“ It would be equal to 102,400 such monster bars as the last. Its lifting power would be nearly 240,869,000,000 tons. The mind is utterly unable to grasp such figures. The whole globe contains 1,200,000,000 inhabitants. If each man, woman, and child, could pull with a force of 100 pounds—a large estimate—to move such a weight would require the united efforts of the inhabitants of two thousand such worlds as this. ”