CHAPTER II.DENSITY AND GRAVITATION.

1st.Density.The sun’s density is one-fourth that of earth, while Mercury’s is one-fifth greater than earth’s, showing that Mercury’s substance must be more than five times denser than the sun’s, whereas it is not 36,000,000 miles distant from it; so near, in fact, and so recently thrown off from the sun as to be thought that human beings could not live upon it. Why is it that this dense substance did not, while a portion of the sun, sink to its centre?

It might be said that on cooling, after being thrown from the sun, the body became more and more dense, the same as is said of earth. But if so why is it that Neptune, seventy-five times farther from the sun, has a density only one-fifth that of earth, and Uranus but a little more; while Jupiter’s density is less than the sun’s, and Saturn’s not even one-seventh that of earth? All of these planets lie in an immensely cold and far away region and were thrown off by the sun, if at all, many years before Mercury, and, according to the supposed theory, should be cold bodies.

Some think, with apparent show of reason, that before planet-making began the heavier materials of the general mass had gravitated toward the centre, while the lightersubstances remained near the surface. “If so,” to quote the words of Prof. Winchell, “the first planets separated would contain more of the substances which, at temperatures familiar to us, make gases and water. Similarly, the later planets disengaged would acquire a large proportion of the substances which form solid rocks. In the case of the earth we may suppose that the greater part was rock-making material, since the earth’s specific gravity is so high; but watery stuff in sufficient amount to provide for oceans and rains, went off with the rock-material, and with these, the lighter stuff for an atmosphere. But in the case of Venus, most of the stuff was rock-material, if not the whole of it; while with Mercury it seems probable that little water-stuff was included. In the opposite direction, Saturn, Uranus, and Neptune must have received a large excess of water and atmospheric stuff. It is rational to suppose that their oceans have always covered the whole land, as ours does more than half. In fact, these bodies must be composed chiefly of water and atmosphere; as their specific gravities are low as water and cork.”[4]

Now if this is a good explanation what shall we say of the sun from which these planets were separated? If it grew more and more solid as it contracted until Mercury, nearly ten times denser than Saturn, was thrown off, why is not the sun denser than Mercury? whereas we find it with but one-fourth the density of earth.

When the sun reached out to earth it must have had a diameter of nearly 200 million miles, but having now contracted to a diameter of less than one million of miles, should it not have a density ten times greater than earth’s, instead of one so much less? For if the solid parts when out at Neptune began to fall toward the sun’s centre, they should have continued to fall until they reached it, or until they had met a density greater than their own. We must remember even at the sun’s present surface a body would fall with much greater velocity than on earth’s surface because of its greater weight. With the density of our earth more than five times that of water, and twice that of solid rock, all heavy substances must gravitate toward its centre; whereas on the surface of the sun the gravitation is more than 27 times stronger. If then the sun were ever a fire-mist reaching out to earth, it would seem that nothing should have prevented the earth from falling with lightning-like speed to the sun’s centre, as its volume was 8,000,000 times larger than now, and even its present volume would hold 900 thousand worlds like ours before it would have a like density.

2d.Gravitation.We see the sun to-day as a perfect sphere, but does a body that is a sphere ever throw off rings by rotary movement? When a body in its revolutions throws off rings by rotating, instead of being spherical it is of a flattened, or grind-stone shape, and the rings are hurled from it by the centrifugal force overpowering the gravitation; hence we cannot think that the sun’s rings,—being of enormous circumference and necessarilyof a light or fluid substance in order to be thrown off,—could form into spheres unless the centrifugal force was extremely great.

Let us suppose that Neptune was thrown off from the sun as a ring, like those we see around Saturn; and, as it is now about 3,000 millions of miles distant from the sun’s centre, before it was detached it must have had a diameter of about 6,000 millions of miles, with a circumference of over 18,000 million miles. Now, as Neptune has about 100 times the volume of earth,[5]its ring could have been no more than 40 miles square; for 1600 square miles multiplied by 18,000 million miles, the distance around that ring, will give more than Neptune’s volume. How then could any substance so exceedingly thin draw to itself this enormous distance of 18,000 millions of miles, any more than a thread a thousand miles in length could draw itself together into a ball, without the thread’s breaking into a million pieces?

Or, take another theory, and instead of supposing that the sun threw off rings, suppose that its surface cooled and formed into a hard crust. Had the inner sun then shrunk away from the outer could that crust have ever formed into a globe that would rotate around the inner sphere, and if not how could Neptune have been formed? Should such a crust have extended around the sun while spread out to Neptune it must have had a circumference of over 18,000 million miles, as did the ring, with a surface of 108quintillions of square miles; so the crust could not have exceeded one-sixtieth of an inch in thickness. If, then, Neptune’s substance in any way resembles earth’s, with a crust of that thickness upon the sun’s surface, it must have collapsed in millions of places instead of having broken away from the sun and formed the globe that we now behold. Chambers tells us: “At the surface of the earth a body set free in space falls 16.1 ft. in the first second of time, with a velocity increasing during each succeeding second. A body similarly set free at the surface of the Sun would start with a velocity 27.4 times as great as that of a body falling at the surface of the Earth. This is equivalent to saying that a pound’s weight of anything on the Earth would, if removed to the Sun, weigh more than 27 lbs. The centrifugal force, due to the rotation of any body diminishes gravity at its surface. At the Earth’s equator the total diminution is1/289part; whilst at the Sun’s equator the centrifugal force is only about1/18,000part the force of gravity. It would be necessary that the Sun should turn on its axis 133 times quicker than it does, for the force of gravity to be neutralized. In the case of the Earth, however, a speed of rotation 17 times as great as it is would suffice to produce the same result.”[6]

By this it is seen the centrifugal force is comparatively insignificant with the sun revolving faster than ever before; for, on the principle that the more a body contracts, the swifter it revolves, it must revolve several hundredtimes faster now than it did when its circumference was at Neptune’s bounds. If this be the case it is difficult to believe there was ever a time that the sun could have been larger than at the present, and have had centrifugal force enough to throw off rings from its surface.

FOOTNOTES:[4]Winchell, “Walks and Talks in the Geological Field,” p. 217.[5]Steele’s “New Descriptive Astronomy,” p. 174.[6]Chambers’ “Hand Book of Astronomy,” p. 6.

[4]Winchell, “Walks and Talks in the Geological Field,” p. 217.

[5]Steele’s “New Descriptive Astronomy,” p. 174.

[6]Chambers’ “Hand Book of Astronomy,” p. 6.

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