GRAVITATIONAL FIELDS & DARK MATTER EXPLAINED

A debut science book offers an overview of several aspects of physics theory.

In this volume, Walsh presents concise explanations of the physics of gravity and gravitational fields as well as the nature of dark matter. The short work is divided into two parts, one for each topic, and relies on both established theory and examples to illustrate the concepts—among others, the author explores Einstein’s “man in a carriage,” a way of depicting how people moving at different speeds observe their surroundings. Walsh also uses Newton’s cradle as a method of explaining how kinetic energy is crucial to motion. The book reviews the effects of gravity as they are experienced on Earth before moving into the wider solar system. Kinetic energy is at the core of the volume’s interpretation of the laws of physics. There are many references to “vis viva,” the historical term for the energy of motion, and the work’s conclusion is that humans do indeed exist within a field of kinetic energy. Walsh clearly has a passion for his subject matter, but there are frequent perplexing and jargon-driven sentences (“This example shows us the energy is a result of a particular action we can specify as motion VS action of stored energy to motion”). Much of the prose would benefit from editing for clarity: “Let us note right now that the subject of energies transforming from one form to another is not needed for this discussion, but we have now noted this”; “Kinetic energy is working on, via in a body (under natural action in the universe, Newton’s first law action), and dark matter is working on a body in its area of existence (perhaps not only this).” In the concluding section, the equations demonstrating the connection between Neptune’s orbital speed and its position in the solar system rely on several apparently arbitrary values, making it unclear to readers exactly how Walsh arrives at an entirely reasonable conclusion. It is evident throughout the book that the author understands the physics involved and has deeply researched the subject, but the substance of his knowledge is not effectively conveyed to readers through the text. The volume may be of more value to those with some expertise in the subject, but novices should look elsewhere for an introduction.

A well-researched but sometimes confusing look at gravity and its effects.