$5.29
Machinery of Gravity
Generalized Equivalence
Book Audience and Approach
The book is addressed to two different audiences: the physics community and non-scientists interested in physics. To accommodate non-scientists, minimal math is used. Whenever math is used, it is accompanied with word descriptions to explain what it means. In addition, each chapter is preceded with simple non-math descriptions of what the chapter is saying.
Main Theme and Content
The main theme of the book is that the machinery of gravity is that all matter is accelerating forever. The book explores this idea, shows it is a feasible interpretation of facts, explains why this is true, applies the teachings to six problems in physics, finding simpler solutions for them, and provides solutions for several where none are at present known.
The six problems are: (1) Bending of starlight; (2) Advance of Mercury's perihelion; (3) Explanation for behavior of spiral galaxies; (4) Expansion of Earth; (5) Anomalous acceleration terms of Pioneer 10 and 11; (6) Accelerated expansion of the universe.
Introduction and Foundations
The book starts by citing Einstein's metaphor of an observer in an accelerated chest unable to distinguish that state from his being "at rest" on the earth. This was his "Principle of Equivalence" that started his development of his gravity theory (General Relativity).
An obvious/intuitive rejection of this idea is that Newton's gravity law cannot be violated, and it would seem (for example) that if I had two spheres of the same size but different densities, the denser sphere would have to get larger than the other one to accommodate its greater gravity field. I use Newton's law to show that one's intuition is wrong.
They stay very nearly the same size because (from Einstein 1905) nothing can go faster than the speed of light, and what remains "almost time invariant" is the ratio of sizes. I end up with two simple equations: (1) Exact size of any object after a long time has passed; (2) Approximate size after a long time has passed. The second of these is the commonly used definition of size (time lapse for a pulse of light to travel the length of some object).
The difference between these two equations is the small quantity that becomes measurable under certain conditions and can be used to test if this expansion idea is valid or not. It also is used in each and every one of the six examples described above to find solutions.
Further Reasoning and Application
The first part of the book explores how to think about gravity in these terms and supplies additional reasoning (mainly related to the second law of thermodynamics) why this view of gravity is possibly (probably) correct. The middle part of the book applies the concept to the six physics problems as stated above. The last part of the book critiques all of it, making clear that further testing is needed.
The expansion of the Earth chapter suggests one appropriate test. An essay on truth is added as a final item.