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Into the Cool, Part II, Chapter 8
Swirl World

   

“The space-time structure of living organisms arises as the consequence of energy flow, and is strongly reminiscent of the non-equilibrium phase transitions that can take place in physicochemical systems far from thermodynamic equilibrium. This organized space-time structure suggests that both quasi-equilibrium and non-equilibrium descriptions are applicable to living systems, depending on the characteristic times and volumes of the processes involved.”

Mae-Wan Ho


Separate from the world, we are yet inextricably connected to it. What is the nature of this relationship? What is the nature of self? In this section we seek the roots of real-world complexity, including the origins of physiology and selves from nonliving systems. A transition from noncoherent, molecule-to-molecule heat transfer to coherent convection occurs in some heated fluids. During the process more than 1022 molecules come into concert. From a statistical point of view, this is ridiculously improbable. Yet the coherence arises naturally from an applied temperature gradient. Nature creates systems, sometimes quite complex ones, "in order to" get rid of gradients and export atomic chaos into the surroundings. "Centripetal," selflike structures arise from material cycles, energy-driven, self-reinforcing networks. Despite the term selfish genes, genes do not have selves: true selves are cells; without proteins and metabolic networks of recursive amino acids and intermediary molecules, genes are impotent, no more "selfish" than an unplugged toaster.

Thermodynamic selfhood comes from dissipative systems that establish boundaries. Far from sealing themselves off from the outside world, their boundaries allow them to continue their operations. Biological selfhood on Earth depends on the semipermeable layer, the ubiquitous lipid cell membrane, which provides a place, at first microscopic, for expansion of nonequilibrium processes. Less complex swirling systems grow and even seem to reproduce without biochemistry, or even chemistry.

Almost perfectly hexagonal Bénard cells are not chemical reactions or biological life but simple physical processes driven by a temperature gradient. If Early's priests had seen one of these systems, they might have sworn it, too, was alive. The Bénard instability is a complexity driven by thermodynamic processes, not whirling computer disk drives.
Bénard's little experiment had big implications. Although the intermolecular distances of whale oil are on the order of 10<min>8 centimeter, the liquid resolved into organized structures 0.1 centimeter in size: a simple heat gradient brings some hundred billion billion (1020) molecules into lockstep. They line up, show coherent motion. Such correlation among molecular trajectories and speeds are striking. They would neither appear nor be predicted in an isolated system. But these systems do not occur in an isolated system. They occur within the organizing confines of a gradient.

Open systems naturally compute answers to the thermodynamic problem of how to come to equilibrium. If we do not see the organized context, the gradients around such structures, we will be mystified. The Bénard instability does not come from a vacuum or a creator. Rather, it works out a previous improbability. It manifests in concentrated form the differentiation it helps destroy.


Bénard-Rayleigh cells.
A
, Bénard-Rayleigh convection in a rectangular container. In Bénard-Rayleigh experiments a lid touches the upper surface of the working fluid. Bénard experiments have air as their upper surface. Here counter-rotating convection with sausage-shaped forms align themselves with the shorter side of the rectangular container. B, Bénard-Rayleigh convection in a 20-centimeter-diameter circular dish with silicone oil 0.765 centimeter thick. These rolls go to the bottom of the heated dish. Each roll is 0.65 centimeter across. Here are billions of molecules spontaneously forming a coherent macroscopic pattern and process to dissipate a heat gradient. C, Square Bénard-Rayleigh convection cells under a glass lid in a square container. The shape of the container determines the form or the pattern in Bénard-Rayleigh convection. (Photographs courtesy of L. Koschmieder.)


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Part II: The Complex

8. Swirl World

9. Physics' Own "Organisms"

10. Whirlpools and Weather



A set of Bénard cells.
In this experiment Koschmieder (1991) used a 1.9-millimeter-deep layer of silicone oil in a 10.5-centimeter-diameter dish. The silicone is under a 0.4-millimeter-thick layer of air, which is under a uniformly cooled sapphire lid. The cells average 0.625 centimeter across, with hundreds of millions of molecules in a highly organized process making up macroscopic dynamic structures. The process is initiated from warm soft spots in the oil surface that give rise to surface-tension effects, and from convection with hot material rising at the center of the cell. The oil is heated from below and rises in the center of the cells, cooling at the cell surface and sinking along the outside edges of the cells. There is no chemical or biological process involved in these steady-state structures. (Photograph courtesy of L. Koschmieder



A Bénard system going from linear to nonlinear states, from conduction to convection. The fluid inside the container is heated from below, and the top of the apparatus acts as a cold sink. The temperature profiles inside the apparatus change from an equilibrium isothermal state of molecular chaos in A, to a conductive state in B and a convective state in C. Once heat is applied to the bottom of the system, all the dissipation (in this case heat flow, Q) occurs via conduction and molecule-to-molecule interaction. When the gradient reaches a critical value, a transition to convection occurs. The more the system moves away from the equilibrium state, the more exergy is destroyed, the system produces more entropy, and more work is needed to maintain the system in a nonequilibrium state. In D the heat flow Q or dissipation through a Bénard cell is plotted against the gradient applied to the system. Of interest is the abrupt transition from conduction to convection at the critical threshold. Once the system is "organized" via convection, it has higher dissipation-heat flow rates. (Adapted from Schneider and Kay 1994b.)

© 2005 Hawkwood Institute Eric D. Schneider Into the Cool