Seven Ideas that Shook the Universe by Nathan Spielberg and Bryon D. Anderson
Scientific revolutions are often like political revolutions. A previous paradigm has to give way to new forces or ideas that attempt to correct or improve upon (or flat out replace) what has come before. Rejecting a comfortable if inaccurate system is not easy. But it happens throughout history and usually is an improvement. This dramatic sweep of change is the central conceit behind Seven Ideas that Shook the Universe. Nathan Spielberg and Bryon Anderson go through seven fundamental changes or advancements (sometimes the change is just adding onto what came before) in science. They have a flair for the dramatic (hence the hyperbolic book title) and communicate the ideas within their historical context. This helps the reader to understand what's so revolutionary about the idea and how the idea is an advancement on what came before. The book is very readable, though later chapters are more challenging. Here are the seven ideas:
- Copernican Astronomy--Starting from the ancient Greeks (who used data from the Egyptians and Mesopotamians), the authors look at the shift from a geocentric to a heliocentric view of the solar system. The Greeks were aware of both theories but favored the geocentric; their opinion was dominant for 1800 years until seriously questioned by Nicolaus Copernicus, a Polish astronomer working in the early 1500s. He published his heliocentric theory as a theory that made calculating calendars and planetary positions easier, even though not more accurate, than the Ptolemaic theory dominant since circa AD 150. As data collection grew more thorough and more accurate (the telescope wasn't invented until the early 1600s), the heliocentric theory gained more traction, though it still didn't achieve universal acceptance until Newtonian Mechanics came along.
- Newtonian Mechanics and Causality--Galileo worked out all sorts of information about the acceleration of falling objects (even if he probably didn't drop stones from the Leaning Tower of Pisa). He also recognized the principle of inertia, that an object in motion will stay in that same motion until something else acts upon it. The day after Galileo died, Isaac Newton was born. He was a brilliant mathematician who used both inductive reasoning (using data and experiments to reach conclusions) and deductive reasoning (using principles to reach conclusions) to work out a simplified and unified system that explains all forms of motion, from planetary interactions to horses drawing carts. His three laws of motion, along with laws on conservation of mass and momentum and his universal law of gravitation, described motion in the universe almost perfectly. He inspired other scientists to build on his work or to look for fundamental laws in other fields of human knowledge (like economics or sociology). His system gave rise to the idea of a clockwork universe, where everything is interconnected and predictable, given enough information.
- The Energy Concept--One component of reality that Newton's system didn't fully explain was energy. His laws cover motion, which is like kinetic energy. His system does not explain potential energy or heat. With the advent of the steam engine in the 1700s, scientists worked on a theory to explain how heat works. The popular theory at the time was that heat was a caloric fluid inseparable from items that had it. The theory couldn't explain everything, especially in the case of friction. Two hands rubbing together produce heat without a heat source, so how can caloric fluid transfer? British physicist James Joule devised an experiment in the 1840s that shifted thinking from the caloric-fluid model to one based on movement of molecules, the accepted theory today.
- Entropy and Probability--In making heat engines more efficient, scientists discovered another principle--entropy. No engine is perfectly efficient, converting heat energy into equivalent work. There's always some energy that radiates off or is "lost" somewhere in the process. Entropy is not a thing in itself; rather, it is a parameter measuring the internal energy state of a system. Oddly enough, the more entropy a system has, the less energy is available to transform into other forms of energy (kinetic, potential, radiant, etc.). The energy falls into a more disordered state and the process cannot be reversed. If applied on the largest scale, i.e. assuming the universe is a closed system, eventually the energy of the universe will be less and less available until it reaches a maximal state of disorder and dispersion and life is no longer viable. Such a process will take a long time, much longer than our lifetimes.
- Relativity--The discovery of relativity started with Galileo and Newton. Newton gave definitions of "absolute" space and time but recognized that in different frames of reference, different measurements were possible. With further discoveries about the nature of light and electromagnetism in the 19th century, new interest in determining the absolute speed gave rise to a variety of experiments to detect ether. Ether was thought to be the medium through which electromagnetic waves traveled. All attempts to detect ether failed, eventually leading scientists to work out a theory of special relativity, in which there is no way to explain the medium through which electromagnetic waves travel, rendering ether into a meaningless concept. Albert Einstein was the first to publish the theory, though other scientists were close. Einstein was far ahead of others when he published his theory of general relativity, applying the principles of accelerated frames of reference as well as inertial frames of reference. (If you want to understand the difference, you'll have to read the book because I just barely grasp it and thus can't summarize it here).
- Quantum Theory and the End of Causality--Much like the title of the book, this chapter's title is a bit of hyperbole. Quantum Theory isn't so much the end of causality as it is the end of certitude. According to Newtonian mechanics (i.e. classical physics), if one knows the position and motion of every object in the universe than every last thing is predictable, i.e. we live in a strictly clockwork universe. Quantum Theory, in an attempt to explain anomalies that arise with classical physics in extreme cases (extreme temperatures or extremely small sizes), applies wave theory to matter as well as to energy. But the application has ambiguity, because the subatomic particles of matter are so small that any attempt to measure their position or velocity will alter that position or velocity, rendering the data collected not so objective as science demands. The book gives a fairly good description of how Quantum Theory is applied in other fields of human knowledge (sociology, economics, etc.) and how the analogy between fields of knowledge can be helpful or unhelpful in grasping concepts. There's also an interesting discussion of how helpful models are in explaining scientific theories. Quantum Mechanics has brought many scientists to the point of rejecting models and instead using mathematical formulas in the interest of having a more accurate description of reality.
- Conservation Principles and Symmetries--When scientists got to the point of studying the particles that make up the nucleus of an atom, they discovered that the conservation principles recognized since Newton still apply even on the sub-nuclear level (even smaller than the sub-atomic level!). New principles had to be added to explain observed characteristics of sub-nuclear particles. These principles include the groupings of particle families in symmetrical patterns. The authors then describe the quark model that is accepted by scientists as a correct understanding of sub-atomic reality.
The book is very well written. The science is not dry and technical (for the most part). The authors also write about the impact of scientific discoveries on other fields of human knowledge. Providing both the history and the context of physics makes it a much more accessible subject.
The version of the book I read is the first edition, published in 1987. A second edition was published in 1995 with updated material and a third edition in 2006 which according to Amazon is not available. Maybe if it is reprinted I will get it. From what I've read online, it looks like this text is used widely as a "history of physics" survey. Naturally, a lot has changed in thirty years for the final chapter, so it is probably the part that had the most updating with new information.
Highly recommended, even with thirty-year-old information!