Person:

Chaisson, Eric

Complex systems throughout Nature display structures and functions that are built and maintained, at least in part, by optimal energies flowing through them—not specific, ideal values, rather ranges in energy rate density below which systems are starved and above which systems are destroyed. Cosmic evolution, as a physical cosmology that notably includes life, is rich in empirical findings about many varied systems that can potentially help assess global problems facing us here on Earth. Despite its grand and ambitious objective to unify theoretical understanding of all known complex systems from big bang to humankind, cosmic evolution does have useful, practical applications from which humanity could benefit. Cosmic evolution’s emphasis on quantitative data analyses might well inform our attitudes toward several serious issues now challenging 21st-century society, including global warming, smart machines, world economics, and cancer research. This paper comprises one physicist’s conjectures about each of these applied topics, suggesting how energy-flow modeling can guide our search for viable solutions to real-world predicaments confronting civilization today.

Nature's 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 evolution's 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.

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.

Evolution, broadly construed, has become a powerful unifying concept in much of science – not only in the biological evolution of plants and animals, but also in the physical evolution of stars and planets, and the cultural evolution of society and its many varied products. This paper (1) explores the bulk structure and functioning of open, non-equilibrium, thermodynamic systems relevant to the interdisciplinary field of astrobiology, (2) places the astrobiological landscape into an even larger, cosmological context, (3) defines life, complexity and evolution writ large, (4) claims that life depends ultimately on the expansion of the Universe and the flow of energy derived therefrom and (5) proposes a quantitative metric to characterize the rise of complexity throughout all of natural history. That metric is neither information nor negentropy, for these inveterate yet qualitative terms cannot be quantified, nor even defined, to everyone's satisfaction in today's scientific community. Rather, the newly proposed metric is normalized energy flow, a revision of a long-cherished term – energy – that is physically intuitive, well defined and readily measurable. All ordered systems – from rocky planets and shining stars, to buzzing bees and redwood trees – can be best judged empirically and uniformly by gauging the amount of energy acquired, stored and expressed by those systems. Appeals to anthropism are unnecessary to appreciate the impressive hierarchy of the cosmic evolutionary narrative, including a technological civilization that now embraces an energetics agenda designed to better understand, and perhaps to unify, all the natural sciences.

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 Sun's natural aging—which causes an approximately 1% luminosity rise for each (10^{8}) 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.

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 Nature's many varied complex systems, potentially dictating their natural selection on vast spatial and temporal scales.

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.

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.