Eric J. Chaisson

Long‐Term Global Heating from Energy Usage

Even if civilization on Earth stops polluting the biosphere with greenhouse gases, humanity could eventually be awash in too much heat, namely, the dissipated heat by-product generated by any nonrenewable energy source. Apart from the Suns natural aging—which causes an approximately 1% luminosity rise for each 108 years and thus about 1°C increase in Earths surface temperature—well within 1000 years our technological society could find itself up against a fundamental limit to growth: an unavoidable global heating of roughly 3°C dictated solely by the second law of thermodynamics, a biogeophysical effect often ignored when estimating future planetary warming scenarios.

Energy rate density. II. Probing further a new complexity metric

Appraisal of the concept of energy rate density continues, as both a potential quantitative metric for complexity studies and a key feature of a unifying hypothesis for the origin and evolution of material systems throughout Nature writ large. This article extends a recent study reported in this journal, hereby analyzing normalized energy flows for an array of complex systems experiencing physical, biological, and cultural evolution. The results strengthen the comprehensive scenario of cosmic evolution in broad and general ways yet with much deep, empirical evidence.

Energy rate density as a complexity metric and evolutionary driver

The proposition that complexity generally increases with evolution seems indisputable. Both developmental and generational changes often display a rise in the number and diversity of properties describing a wide spectrum of ordered systems, whether physical, biological, or cultural. This article explores a quantitative metric that can help to explain the emergence and evolution of galaxies, stars, planets, and life throughout the history of the Universe. Energy rate density is a single, measurable, and unambiguous quantity uniformly characterizing Natures many varied complex systems, potentially dictating their natural selection on vast spatial and temporal scales.

The cosmic environment for the growth of complexity.

The unifying scenario fo cosmic evolution is outlined by following the natural changes among radiation, matter and life in standard, big-bang cosmology. Using aspects of non equilibrium thermodynamics, especially energy flow considerations, we argue that it is the contrasting temporal behavior of various energy densities that have given rise to the environments needed for the emergence of galaxies, stars, planets, and life forms. We furthermore argue that a necessary (though perhaps not sufficient) condition--a veritable prime mover--for the emergence of such ordered structures of growing complexity is the expansion of the Universe itself. Neither demonstrably new science nor appeals to non-science are needed to explain the impressive hierarchy of generative change, from atoms to galaxies, from cells to society.

A hydrogen and helium radio recombination-line survey of galactic H II regions at 10 GHz

The results of a radio recombination-line survey of 20 galactic H II regions are used here as a diagnostic probe of the Galaxy. At a frequency of 10.2 GHz, we do not find appreciable departures from local thermodynamic equilibrium; each H II region can be satisfactorily characterized by an average electron density and temperature. The nebular electron temperature is found to decrease monotonically by about 3000 K between 13 and 5 kpc from the galactic center. This Galaxy temperature gradient most probably results from an increase in the heavy-element abundance by a factor of about 5 from 13 to 5 kpc from the galactic center. The observed temperature and suggested chemical gradients may extend to the galactic center, but observations from that region are difficult to interpret unambiguously. The ionized helium abundance also varies among different nebulae. However, since radio observations do not provide a reliable means of estimating the amount of neutral helium within H II regions, it is not feasible to determine Galaxy gradients in the total He/H ratio.

A Singular Universe of Many Singularities: Cultural Evolution in a Cosmic Context

Nature’s myriad complex systems—whether physical, biological or cultural—are mere islands of organization within increasingly disordered seas of surrounding chaos. Energy is a principal driver of the rising complexity of all such systems within the expanding, ever-changing Universe; indeed energy is as central to life, society, and machines as it is to stars and galaxies. Energy flow concentration—in contrast to information content and negentropy production—is a useful quantitative metric to gauge relative degree of complexity among widely diverse systems in the one and only Universe known. In particular, energy rate densities for human brains, society collectively, and our technical devices have now become numerically comparable as the most complex systems on Earth. Accelerating change is supported by a wealth of data, yet the approaching technological singularity of 21st century cultural evolution is neither more nor less significant than many other earlier singularities as physical and biological evolution proceeded along an undirectional and unpredictable path of more inclusive cosmic evolution, from big bang to humankind. Evolution, broadly construed, has become a powerful unifying concept in all of science, providing a comprehensive worldview for the new millennium—yet there is no reason to claim that the next evolutionary leap forward beyond sentient beings and their amazing gadgets will be any more important than the past emergence of increasingly intricate complex systems. Nor is new science (beyond non-equilibrium thermodynamics) necessarily needed to describe cosmic evolution’s interdisciplinary milestones at a deep and empirical level. Humans, our tools, and their impending messy interaction possibly mask a Platonic simplicity that undergirds the emergence and growth of complexity among the many varied systems in the material Universe, including galaxies, stars, planets, life, society, and machines.

The Natural Science Underlying Big History

Natures many varied complex systems—including galaxies, stars, planets, life, and society—are islands of order within the increasingly disordered Universe. All organized systems are subject to physical, biological, or cultural evolution, which together comprise the grander interdisciplinary subject of cosmic evolution. A wealth of observational data supports the hypothesis that increasingly complex systems evolve unceasingly, uncaringly, and unpredictably from big bang to humankind. These are global history greatly extended, big history with a scientific basis, and natural history broadly portrayed across ∼14 billion years of time. Human beings and our cultural inventions are not special, unique, or apart from Nature; rather, we are an integral part of a universal evolutionary process connecting all such complex systems throughout space and time. Such evolution writ large has significant potential to unify the natural sciences into a holistic understanding of who we are and whence we came. No new science (beyond frontier, nonequilibrium thermodynamics) is needed to describe cosmic evolutions major milestones at a deep and empirical level. Quantitative models and experimental tests imply that a remarkable simplicity underlies the emergence and growth of complexity for a wide spectrum of known and diverse systems. Energy is a principal facilitator of the rising complexity of ordered systems within the expanding Universe; energy flows are as central to life and society as they are to stars and galaxies. In particular, energy rate density—contrasting with information content or entropy production—is an objective metric suitable to gauge relative degrees of complexity among a hierarchy of widely assorted systems observed throughout the material Universe. Operationally, those systems capable of utilizing optimum amounts of energy tend to survive, and those that cannot are nonrandomly eliminated.

Using complexity science to search for unity in the natural sciences

Introduction Nature writ large is a mess. Yet, underlying unities pervade the long and storied, albeit meandering, path from the early Universe to civilization on Earth. Evolution is one of those unifiers, incorporating physical, biological, and cultural changes within a broad and inclusive cosmic-evolutionary scenario. Complexity is another such unifier, delineating the growth of structure, function, and diversity within and among galaxies, stars, planets, life, and society throughout natural history. This brief essay summarizes a research agenda now underway not only to search for unity in Nature but also, potentially and more fundamentally, to quantify both unceasing evolution and increasing complexity by modeling energy, whose flows through nonequilibrium systems arguably grant opportunities for evolution to create even more complexity.

Follow the Energy: The Relevance of Cosmic Evolution for Human History

1 See David Christian, Maps of Time: An Introduction to Big History (University of California Press, 2004); and “World History in Context,” Journal of World History 14 (2003): 437-458. On “big history,” see Marnie HughesWarrington, “Big History” in Historically Speaking: The Bulletin of the Historical Society (November 2002). The discussion below was prompted in part by writing “History in the Landscapes of Modern Knowledge,” a review essay on John Lewis Gaddis, The Landscape of History: How Historians Map the Past (Oxford University Press, 2002), which revisits two 20thcentury classics on historiography: E.H. Carr, What is History? (Penguin, 1964 [first published in 1961]) and Marc Bloch, The Historian’s Craft, trans. Peter Putnam (Manchester University Press, 1992 [first published in 1953]) and appears in History and Theory 43 (2004): 360-371.

Energy Flows in Low-Entropy Complex Systems

Nature’s many complex systems—physical, biological, and cultural—are islands of low-entropy order within increasingly disordered seas of surrounding, high-entropy chaos. Energy is a principal facilitator of the rising complexity of all such systems in the expanding Universe, including galaxies, stars, planets, life, society, and machines. A large amount of empirical evidence—relating neither entropy nor information, rather energy—suggests that an underlying simplicity guides the emergence and growth of complexity among many known, highly varied systems in the 14-billion-year-old Universe, from big bang to humankind. Energy flows are as centrally important to life and society as they are to stars and galaxies. In particular, the quantity energy rate density—the rate of energy flow per unit mass—can be used to explicate in a consistent, uniform, and unifying way a huge collection of diverse complex systems observed throughout Nature. Operationally, those systems able to utilize optimal amounts of energy tend to survive and those that cannot are non-randomly eliminated.