The true origin of ice ages
If it is true that all planets once possessed ring systems, it follows that the clouds of mineral matter which still surround Jupiter, Uranus and Neptune, also those beneath Saturn’s rings, must consist of former ring matter in later stages of declination.
However, the idea that, in addition to Saturn, other planets had rings, can be discarded without in the least weakening the conception that the present cloudy shrouds of four superior planets are primordial minerals which have not yet descended to the cores. Neither would it lessen the probability that the Earth once was surrounded by a shroud like five other planets are.
Velocities Governed by Law
Assuming that Earth did once have rings, let us now try to imagine what happened to them and incidentally what will in time happen to the rings of Saturn. Of course we do not know how fast the rings were rotating; neither do we know the force of gravity at the time. Possibly it may not have been much less than it is now, inasmuch as the total terrestrial mass was then probably about the same as today. We do know, however, that the orbital radius of any particle, whether it were a molecule of water or a ten-ton boulder, would be determined by its velocity. Assuming that gravity were then the same as it is today, we know that matter revolving in the plane of the equator, at a distance of 4,000 miles from the core’s center, would require a velocity of approximately 17,500 miles per hour to overcome the pull of gravity and remain aloft. At a distance of 26,000 miles from center, it would need a velocity of only 6,800 miles per hour (effecting revolution in 24 hours); at 100,000 miles from center, the required velocity would be roughly only 3,475 miles per hour. Required speeds at other radii would be proportional.
The velocity of revolution required at any radius to develop centrifugal force exactly equal to gravital force at that radius is known as “orbital speed.” Should the velocity of material at a certain radius be decreased in any amount below orbital speed at that radius, the material would decline toward the core. As it thus declined, the difference between its velocity and orbital velocity would progressively increase. Hence its declination would continue at an increasing rate and never stop until the material reached the core. This would be true unless its velocity on the way down were, in some manner, stepped up to orbital speed.
On the other hand, if the velocity of a particle at any distance from center was greater than orbital speed at that distance, the particle would begin to recede farther from center and, provided it maintained the same velocity, would keep on receding until it eventually escaped from Earth’s gravitational control. This would be true for the reason that the force of gravity acting upon it would diminish as the distance of the particle from center increased. That some ring matter did so escape seems entirely possible. We know that space within the Sun’s control contains vast numbers of meteoric particles of every size. These, at some time, conceivably, could have been parts of planetary primordial atmospheres.
Light Minerals Driven Highest
It seems reasonable to assume that when the many volatile elements and compounds were formed, they must have been driven aloft by the intense heat to distances more or less proportional to their specific gravities and relative volatilities. Water, being comparatively light and highly volatile, would be repelled to greater heights, whereas iron and other heavier and more refractory materials would be repelled to lesser heights.
If the resulting relative distances from center of the different materials were retained as the materials gravitated toward the equatorial plane, the outer portions of the ring system would be composed predominantly of water, carbon and other light elements and compounds. The inner portions would consist largely of heavy metals and more refractory minerals. As a result, more or less separate rings, with spaces between, would tend to form. The rings of Saturn clearly illustrate the idea.
The velocities which we have postulated would have been necessary at various radii to prevent the immediate descent of the suspended material after heat ceased to repel it, do not seem at all excessive as compared to the measurable speeds of rotating atmospheres surrounding other planets. Neither the mentioned radius of 26,000 miles, which might possibly have been the radius of the innermost part of the disc material, nor a radius of 100,000 miles, which might be assumed for the outermost portion, would seem at all fantastic, judging by the example of Saturn. However, either radius, also the velocity of rotation, could well have been greatly different without lessening the logic of the theory, which is all that concerns us. Furthermore, all the factors mentioned undoubtedly changed as evolution progressed.
Declination of Rings
If, then, all atmospheric matter in the original spherical mass which had not yet descended to Earth’s core finally reached the equatorial plane and gravitated into disc form like the rings of Saturn, how did these materials thereafter return to Earth? It is obvious that they could not return in any event or manner unless and until their velocities were reduced below orbital speeds. We know that there were forces in existence which would have gradually so reduced them. Certainly if the Moon were then in existence, revolving at approximately its present speed, it would have created tides in the primordial atmosphere to pull backward, thus retarding rotational velocity. We can have no doubt whatever that the Moon did exist and did revolve around Earth certainly at the very recent times, geologically speaking, when the known ice ages occurred. We can thus confidently conclude that Earth’s revolving rings did gradually lose velocity and hence did decline toward the core. Let us try to visualize what would then occur.
There can be no doubt that since life first appeared Earth has had an air atmosphere very similar to the present one. As and when a declining increment of the ring matter came, in due time, into contact with the outer reaches of Earth’s true atmosphere—the air envelope—which would in a measure resist its declination and also quicken the reduction of its speed, it would tend to widen from its thin disc form and spread each way toward the poles, forming two bands or belts, one on each side of the equator. These bands would gradually gravitate spirally toward the poles in the exact reverse manner, due to their declining speed, from the way we saw that atmospheric matter in the former spherical shape was impelled toward the equator. Inasmuch as the various rings aloft were to some extent separated from each other, their increments would reach Earth’s air envelope at separated times, each to divide and form two additional bands to gravitate poleward. That the latter process was very slow, we have ample confirmation in the examples of our sister planets.