CALCULATING THE COSMOS

Stewart (Mathematics/Univ. of Warwick; Professor Stewart’s Incredible Numbers, 2015, etc.) tackles the universe in this latest compendium of facts and fancy.

The prolific popularizer shows that he is not only a polymath in the sense that he is a master of all fields of mathematics, but also in his comprehension of physics, astronomy, and cosmology. The author begins by chronicling how humans throughout history have thought about the universe, from Babylonian and Greek thinkers to Galileo and Newton. Stewart then pauses to note that Newton’s laws of motion and gravity have been fundamental to our understanding of celestial motions and, in many cases, still work. Then Einstein upset the apple cart with his observations confirming findings that while the speed of light is a constant, space-time is not flat, á la Newton, but curved due to the gravitational effects of stars and other objects with mass. From this point on, the author describes mathematical models developed to explain observations and revisions of the models in light of better data. The problem is that the models are always simplifications, Stewart observes, and when better observations contradict the model, either the model has to change or the observations are proved to be wrong. Today, the accepted model of the origin of the cosmos is the Big Bang that happened 13.8 billion years ago, a model that has been modified by the concepts of inflation, dark matter, and dark energy. Alas, these introduce other problems—not to mention recent observations that some stars appear to be older than 13.8 billion years. By the end of the book, readers are likely to be daunted by current models and controversies, but that seems to be Stewart’s point: we are human, we speculate, we constantly revise—and we also write science fiction.

A word to the wise: this is not cosmology for dummies. Parts of the text are nearly impenetrable, and Stewart’s compact style provides few diagrams or even equations. However, he effectively shows that time and technology will evolve ever better calculations of the cosmos.