Benish

Rade, Without having looked into DoclorDick's or Aristotle's work myself, by your description it seems they are similar in speculating and philosophizing about physical reality without much actual concern for observable, testable reality itself. In other words, they dwell in the world of abstraction; not in the world of experience. This is true of a large percentage of what passes for gravitational physics these days (as one can deduce by looking at the titles of papers published in many journals). This may well have some beneficial purpose; it should not be discouraged. But the sad thing to me is how the physical world is being neglected. The nature of mass, space, time and gravity are all still very mysterious, as any humble physicist would admit. Given this state of confusion, one should hope that all manner of experiments would be encouraged; that we would be eager to look where we have not yet looked. But this spirit of inquiry has turned largely to navel contemplation, to weaving intricate mathematical meanderings based on untested assumptions that leave physical reality way behind. Michael Faraday lived by his words: It is absolutely necessary that we should learn to doubt the conditions we assume, and acknowledge we are uncertain…In the pursuit of physical science, the imagination should be taught to present the subject investigated in all possible and even in impossible views; to search for analogies of likeness and (if I may say so) of opposition — inverse or contrasted analogies; to present the fundamental idea in every form, proportion, and condition; to clothe it with suppositions and probabilities — that all cases may pass in review, and be touched, if needful by the Ithuriel spear of experiment. Unfortunately, the spirit of Michael Faraday is rare to find anymore, except in children and others whose curiosity has not been squelched by the rigors of academic training.

I'm glad to hear your thoughts on actually doing the experiment. Though it would be cheap and easy compared to the high-budget enterprises that get so much attention, it would not be so simple as just modifying an off-the-shelf torsion balance. The reason is that a torsion fiber would not be suitable as a support for the arm because the resistance increases with angle. Unlike prior applications of a torsion balance, in the present case we need the resistance to be not only extremely small, but also constant throughout the range of motion. This indicates the use of a magnetic or fluid suspension system of considerable delicacy. George Herold, a physicist at the company, TeachSpin in Buffalo, New York has contemplated building one. I understand that my descriptions so far would seem vague and off-the-wall. If you are interested in a more formal defense of the space generation idea, please check out this link: Maximum Force Derived from Basic Physical Principles It's a paper that I submitted to the International Journal of Theoretical Physics a few months ago. The first reviewer wrote that the "manuscript is well written and well illustrated…I would recommend publication." But this was contingent upon correcting a "mistake," which was, however, not clearly specified. After re-submission the paper was rejected. So I sent it to the author of a paper that mine was ostensibly based on. The author's name is Christoph Schiller, whose paper was published in IJTP. In response to my paper, he wrote: "You are courageous in questioning the validity of general relativity…I like the clarity with which you expose all issues involved. I like this kind of clear thinking a lot." The paper presents a derivation (based on special relativity, the equivalence principle and the inverse-square law) of a maximum force with exactly the same magnitude as the maximum force that Schiller derived based on general relativity. Though it is not pointed out till later in the paper, the basis of the derivation is the idea that gravity is a process of the generation of space. It is duly emphasized that the idea is testable with the interior solution experiment.

Thanks for the welcome CraigD! Gravity is usually thought of as a linear force between masses. The clearest way to see its volumetric implications is in the context of cosmology. Gravity is supposed to be "trying" to eliminate the space between bodies, space that was produced by the big bang. It is well known in this context that, if the rate of expansion does not exceed a critical minimum, then gravity will halt the expansion and suck all space out of the universe (aka the Big Crunch). Thus, the standard view of gravity may be described in terms of the elimination of space between bodies. This occurs according to the inverse square law, GM/r^2. Now consider the fact that accelerometer readings all over the globe indicate a positive acceleration, 9.8 m/sec^2. The 1/r^2 makes this quantity a linear acceleration. But the quantity GM by itself has the dimensions of a volumetric acceleration, L^3/T^2. For a sphere it should actually be 4piGM. If gravity is a force of attraction, then this is the contribution each body of matter (M) makes to slowing down the expansion of the universe. What I'm suggesting is that maybe gravity isn't a force of attraction. Instead of eliminating space, maybe matter, via gravity is a source of space. Maybe gravity is the process whereby mass generates space. (This may explain why mass has inertia, as per the original question is this thread.) Concerning the thoughts in your last two paragraphs, I would respond as follows: Most everything we know about gravity is based on observations and experiments conducted outside the surface of large gravitating bodies. This is true of the experiments you have mentioned. The circumstance of falling through the center of a massive body by gravity is significantly different from any experiment so far proposed. What happens when a radially falling object is allowed to fall as long as it will, without colliding? The theoretical prediction is very well known. But in the absence of direct physical evidence, it must be admitted that nobody really knows if the prediction is correct or not. Even if the above speculations as to the nature of mass and gravity are incorrect, simple scientific curiosity (and a desire for completeness) should suffice to warrant doing this basic experiment. This is especially true given that, as you have implied, most other experiments that get funded cost a whole lot more money.

The difference between mass and light can be thought of as the difference between that which is a clock and that which is not. Massive objects "tick"; but light is timeless. This is consistent with relativity theory, where we sometimes find the statement that "time stops for the photon." As for what gives mass its inertia, nobody has yet explained this. One possibility that is vaguely related to Mach's principle, but otherwise new, relates mass to the mechanism for gravity. The dimensions of Newton's constant, L^3/T^2/M, may be thought of as the acceleration of volume per mass. If we think of gravity as the process whereby mass generates space, an intuitive conception of inertial mass follows. Inertia is that property of mass whereby a body resists changes to linear motion, i.e., to motion in one direction. By the above reasoning, this is proportional to the quantity of space that the body is generating in every direction. This possibility can be tested by performing a relatively simple experiment. It's one that has often been discussed as an elementary exercise in Newtonian gravity: Drop an object into a large mass with a hole through its center. Newtonian theory says the object will harmonically oscillate in the hole. Nobody has ever checked to see if this really happens. If the above hypothesis is correct, it will not happen. The test object would not pass the center. For its implications as to the nature of mass and and gravity, doing this experiment should thus be put on a physicist's list of things to do.