Symphony in C: Carbon and the Evolution of (Almost) Everything, by Robert M. Hazen, is an interesting book on the importance and prevalence of Carbon to life on Earth. This was a wonderfully informative book for a science layman like myself. I have some familiarity with basic chemistry and biology from my years in school, but this is not a topic I interact with overtly on a daily basis. This book covered a wide array of topics, organized in a fairly unique way - following the stanzas of an orchestra. Hanzen is an eccentric; his love of many topics, and passion for mineralogy and the study of crystals, has transcended just this seemingly constrained field. Life on Earth is carbon based - all the processes, structures, systems and components that make life possible are either made of, or interact with, carbon systems. Carbon is a unique element - its atomic structure ensures that it is constantly looking to reach a stable atomic number, but it is at the midpoint of 2, and 10, the sweet spots for stable elements. This ensures it can take a variety of methods, from shedding, to gaining, to interacting with numerous other elements, compounds, and itself. This atomic flexibility means carbon is found in numerous processes, molecules, compounds and biological materials globally, and was and is instrumental in the processes of life.
This book discusses these concepts in four parts - Earth, Air, Fire and Water. These sections focus on the crust and mantle, the atmosphere, human production, and life respectively. Carbon is a major component in the Earth's crust and mantle, and many interesting crystals and minerals contain carbon. Hazen is part of the Deep Carbon Observatory (DCO), and organization looking to examine and learn more about the numerous mineral and crystal interactions of carbon. There are thousands of carbon crystals. Most are from just a few types of carbon compounds spread liberally throughout the world, but the majority of the thousands of species of carbon crystals are rare, some located in just one place in the world, and formed from interesting and very local conditions and interactions. Volcanic lakes, rare microorganisms and so on all have the potential to create rare and interesting minerals. Much is unknown about carbon and its mineralogy. Numerous species of crystals are theorized, but have yet to be observed in nature. And the function and composition of the Earth's mantle is theorized but generally unknown.
Air - the atmosphere, is made up mostly of Nitrogen, with large concentrations of oxygen and of course, carbon. One of the hot topics right now is climate change. Carbon is an important component of this. It is one of the main components of many greenhouse gases, including carbon dioxide and methane. These two in particular are the most prevalent. Although natural components of the atmosphere, human life has increased the amount of greenhouse gases in the atmosphere by a large margin, due to our use of fossil fuels. Humans expel more carbon into the atmosphere than all natural processes can annually, and have been doing so for over one hundred years. This has pushed the carbon levels in the atmosphere to much higher levels than they have been in our timeline, although the Earth has experienced atmospheric carbon before. However, this was well before the development of life as we know it. Our use of carbon has probably tipped the carbon cycle - the process that carbon goes through from mantle to atmosphere and back - to areas not seen in some time. The consequences to this are unclear, although a shift in climate patterns is almost certain.
Fire - humans use of carbon and carbonate materials in our industrial processes, and also as the basic block of construction for many molecular structures. This was an interesting and speculative section that examines carbon as a material in many processes. Its bonding ability makes it a key component in many systems. It is intimately tied to our energy processes. While we may be looking to switch over to more renewable fuels, carbon is present in the foundation and composition of windmills, the infrastructure of solar panels, the input of biofuels and so on.
Finally Water - the most big brained section of the book. This is an examination and sometimes musing on life, its composition, how it may have formed, and what it may look like not just on Earth, but throughout our universe. We know life is carbon based on Earth, and Hazen speculates are to how biological materials may have moved from puddles of goo without the ability to reproduce, to living creatures. This process may have happened due to the particular makeup of cells and their need to protect themselves from environmental changes. The development of cell walls to protect molecular material, the joining together of similar molecules to form larger components, the birth of symbiotic relationships where some molecules perform tasks that benefit others, then to organelles, and finally more recognizable life. Something happened here, and we cannot be quite sure of what, although scientists have a much clearer picture than they did 30 years ago. At one time, a debate raged between scientists who believed life was formed from organic materials interacting in calm, sun bathed ponds, and those that believed that life developed due to geothermal venting in the oceans. Both seem likely, and they certainly may both have been correct. This binary debate is not useful, as it constricts the potentially complex situations that encouraged life to emerge. Hazen notes the difficulty with trying to recreate the development of life in the laboratory. This however, may be due to the need for a very large amount of time - it seems life may have developed due to the interactions of molecules and organic compounds in an environment that was both stable for long periods of time, but had enough environmental variability to ensure the need and ability to mutate or potentially build beneficial structures.