Levenson, Thomas. The Hunt for Vulcan: Random House, NY. 2015. ..And How Albert Einstein Destroyed a Planet, Discovered Relativity, and Deciphered the Universe.

Clear, coherent, focused, and entertaining are some of the adjectives that can be applied to this book on how our knowledge of the universe has changed from Newton’s time. It is easily-understood but not condescending, uses matter-of-fact language to explain the amazing advances in what we know about a universe that we have barely begun to understand.

Actually, Einstein did not destroy a planet—he disproved the theory that a planet–Vulcan–existed in an orbit closer to the sun than Mercury. But Levenson uses the 50-year dispute about its existence to explain how scientists work.

Isaac Newton and Edmond Halley (of the comet), and many others in the 1680s laid the groundwork for our understanding of the universe and the physics and mathematics that make that possible. The intelligence and patience of the pioneers of science is the real “back story” of how modern physics has evolved.

The book has three parts. Part 1, Newton to Neptune, (1682-1846) is in itself a fascinating description of how mathematics and physics are basic to unraveling the mysteries of space and time. Before computers, mathematicians had to calculate each equation, sometimes taking years to reach a conclusion.

Part 2, Neptune to Vulcan, describes Newton’s theory was accurate enough to use to describe the observable world, that is, what might be calculated using measurements by the instruments of the time. But mathematicians went beyond physics, and astronomers projected what might exist according to their calculations but had not yet been discovered. Thus, Neptune was expected to be found, according to the relationships of other planets to the sun and to each other, but had not been seen. When it did appear where it had been predicted, it raised issues that Newton’s mathematics could not resolve. One of them was the finding that during Mercury’s transit of the sun, it wobbled in its orbit. This raised the possibility of “action” upon it by an undiscovered planet close to and hidden by the son. Newton’s mathematics could not resolve this question.

Part 3 describes the disagreement among observers, on how the findings were inconclusive, because the mathematicians could not reconcile observations with predictions of Vulcan’s position, or even its existence. Einstein’s “six months,” in which he wrote four papers that have become the basis of the way we now perceive our world, is described in detail. The respect we owe these scientists for advances in our knowledge and the development of technology they inspire cannot be overestimated.

The most important aspect of this book is how clearly it explains the way mathematicians, astronomers and other scientists have been able to advance our world over the past relatively few years, in unimagined ways and astonishing outcomes. Without Newton and those who followed him, and then Einstein and those who came after, our world might still be a largely agricultural place where time, space and the stars, and our place in them, are still unknown and little understood. In 229 pages, Levenson makes clear how important this half-millennium of time has been to how we live today.

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