Gravity is one of the most familiar everyday phenomena, yet it has mystified scientists and laymen for centuries. Even today, although the current official position on gravity is a continual "space-time warping" around objects - a claim from Einstein's General Relativity theory, it is also still widely considered an endless attracting force emanating from objects, as claimed in Newton's gravitational theory. Setting aside the troubling implications of two different physical descriptions of gravity in our science for the moment, it turns out that the behavior of a simple spring may hold the final answer to this age-old mystery.
Consider what happens when a loosely coiled spring is stretched apart from both ends while laying on a tabletop, as shown below in the left-hand frame. The opposing forces spread equally across the spring, causing an equal coil spacing across the spring, which also occurs whether either force pulls fully from the very end or is divided to pull directly on each coil:
However, with only a single continual pulling force on one end, shown on the right, the coils stretch more at the leading end as they strain to continually accelerate the ongoing resisting inertia of the rest of the spring. In this case, there is successively less stretch toward the trailing end as there is successively less trailing-coil mass to cause inertial drag.
This deceptively simple experiment has enormous implications for both Newton's gravitational force and Einstein's "warped space-time' theory of gravity - and for understanding the true physical nature of gravity itself. The first important point is that it highlights a widely overlooked but critical error surrounding Einstein's famous "space elevator" thought experiment, which forms the foundation of his Principle of Equivalence and his later associated General Relativity theory of gravity.
The Erroneous "Principle of Equivalence"
Einstein claimed that all experiences and experiments occurring inside a constantly accelerating elevator moving upward in deep space - far from any gravitational influence - would be indistinguishable from them occurring under the influence of Newtonian gravity on Earth. This claim is known as the Principle of Equivalence, and forms the cornerstone of gravitational physics in today's science; however, the simple spring experiments just discussed can be used to show that this is an erroneous claim, with enormous implications for our understanding of gravity.
Similar to the left-frame tabletop experiment above, a hanging spring on Earth should have two opposing forces distributed across it, equally spreading its coils - the force of gravity pulling downward and the restraining force that effectively pulls upward. However, as in the right-frame of the above tabletop experiment, a spring attached to the ceiling of Einstein's continually accelerating deep-space elevator, far from Earthly gravity, should exhibit the unequal coil distribution of a spring pulled from only one end:
So, this shows that Einstein's claimed "Principle of Equivalence" between Newtonian gravity and pure acceleration in deep space must be wrong - the effect of being accelerated upward in space must differ from an attracting force emanating from a planet. If Einstein had remained faithful to his original "space elevator" inspiration, rather than developing his General Relativity theory for equivalence to Newton, he would have produced a new understanding of gravitational physics that clearly differed from Newton's, and which could be easily tested by a simple hanging spring experiment. Instead, Einstein effectively abandoned his space-elevator inspiration in favor of a mistaken "Principle of Equivalence" to Newton, and a related "warped space-time" proposal for the physics of gravity in his General Relativity theory.
A Verifiable Revolution in our Understanding of Gravity
But why concern ourselves with this hanging spring issue in a deep-space elevator, especially if we already know that Einstein's Principle of Equivalence and General Relativity theory are widely accepted today, and supposedly even proven by highly sophisticated experiments? The reason is because this very same hanging spring experiment can be performed by anyone - by simply suspending a well-known spring toy from one end, showing that gravity on Earth behaves precisely as in Einstein's original space-elevator inspiration, and not as in either Newton's "gravitational force" theory or Einstein's equivalent "warped space-time" General Relativity theory. This simple experiment shows a hanging spring with an unequal distribution - here on Earth - which could only occur if it were continually accelerated upward from its suspended end, and not stretched uniformly by an attracting "gravitational force" or equivalent "space-time warping".
This further shows why no solid scientific explanation for the operation of Newton's proposed attracting force has ever been settled upon, and nor has its apparently endless power source ever been identified or explained. This also means that Einstein's efforts to mirror Newtonian gravitational theory in his General Relativity theory are equally verifiably in error, and that the experiments presented as proof were conceived and designed such that their claimed "success" actually constitutes no particularly meaningful result at all.
Could the Evidence Still Support Today's Gravitational Theories?
The preceding discussion shows that Newton's theory of an attracting gravitational force is readily disproven by a simple hanging spring, as is Einstein's "warped space-time' General Relativity theory, which was deliberately designed to be functionally equivalent. But before addressing what all of this means, it can still be tempting to dismiss the above discussion with intuitive support for today's gravitational theories, such as the following:
"The coils at the top of a hanging spring simply bear the weight of the rest of the spring hanging below. And those further down have fewer coils below them, thus less weight to bear, stretching successively less, resulting in more stretch at the top and successively less toward the bottom - a non-uniform hanging spring.'
This may initially sound reasonable enough, but the first hint of a flaw in this logic is that it is at odds with the earlier tabletop experiment showing that two opposing forces (such as gravity pulling down and a restraining force pulling up) should result in uniform coil spacing. So, what is the logical flaw in the above reasoning? It is the presumption that the strain caused by weight is solely due to a downward pull from gravity, and that this strain accumulates, with the weight of the lower coils adding to greatly stretch the upper ones.