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Degrees of Scientific Impossibility
on September 24, 2008
Will something that is impossible now eventually become possible? In order to answer this question, the author has divided various potentially outrageous ideas into three levels of impossibility, based on current and expected future technological capabilities and the known laws of physics: Class I impossibilities, occupying over 60% of the book, Class II impossibilities and Class III impossibilities. The higher the class level, the more impossible (or farther in the future) the possible realization of the idea is perceived to be. In progressing along these classes, the author goes from practical nuts-and-bolts solutions to various problems that may be possible in a matter of decades to centuries (Type I), to dreams whose realizations may never happen according current very abstract ideas that are at the very forefront of scientific thinking and thus very far removed from our everyday experience (Type III). The writing style is clear, friendly, authoritative and quite engaging. The book contains no diagrams whatsoever. In most cases, they are not really essential because of the author's excellent ability to express complex ideas into clearly understandable prose. However, in a few cases, diagrams would have been quite welcome. Technical terms are clearly explained as they occur so that anyone could read this book and learn a great deal from it. However, science buffs would probably appreciate it the most.
On a more technical note, on a couple of occasions the author has pointed out that when an electron and an antielectron (positron) meet, they annihilate producing "gamma rays at an energy of 1.02 million electron volts or more" (p. 184) and "annihilate one another and create a gamma ray" (p. 278). The first statement can be misleading while the second one is incorrect and is likely a misprint. When an electron and a positron meet in free space, they annihilate producing two gamma rays (not one) of energy 0.511 million electron volts each (or more, depending on their relative kinetic energies when they meet); the total gamma ray energy released being (at least) 1.02 million electron volts. Production of two gamma rays is essential to conserve momentum, i.e., total momentum before the collision must equal total momentum after the collision, which is impossible if only one annihilation gamma ray is produced.