Life, Universe, and the Second Law


On fundamental things. A theory of everything, or of everything else?

Derek Hitchins

The Second Law of Thermodynamics is a cornerstone of physics. It comes in many forms, including:

The processes most likely to occur in an isolated system are 
those in which the entropy either increases or remains constant

Physicists use this proposition to predict that the Universe will eventually become cold, inert and lifeless in some far off future.

All the more surprising, then, is the recent discovery of a galaxy, less than 100 million years old, in which new stars are forming, i.e., entropy is apparently reducing. How can this be consistent with the Big Bang and the Second Law? Well, of course the Second Law is statistical. If the Universe is an isolated system, and if the average entropy throughout the Universe is still increasing or remaining constant, then local reductions in entropy need not confound the Law, provided there are equivalent increases elsewhere. But, they still take some explaining….

Which brings into question, just how useful is the Second Law in everyday life? Life appears to confound it: as we are born, develop, grow and mature, so our bodies become more ordered. Eventually, decay sets in and entropy wins, but not before life has gained considerable ground. Civilisations are even more of a challenge to the Second Law. They emerge from social chaos, grow, develop, refine, evolve, morph, fluctuate and endure, sometimes for thousands of years. Eventually, they too decay, often with a resounding collapse, only to be replaced by another, and another.

This observation has given rise to the organismic analogy, in which entities such as organizations, governments and civilisations, which are clearly not organisms, are observed to behave in ways analogous to organisms. I.e., they are made from many different interacting parts, yet they act as a unified whole, and they have a life-cycle, at the end of which they come to an end; often a sudden, collapsing end. The former Soviet Union presents a classic example. It took many decades to form and develop as a single bloc, but collapsed, domino-style, in only a few weeks, breaking up into its former constituent nation states, which then started to reform into different groupings. The cycle continues.

The Second Law refers to isolated systems. The former Soviet Union was certainly not isolated: living organisms and civilisations are not isolated. Looking around us in the real world, it is difficult to find an isolated system. If a system were truly isolated, it would receive no inputs and give no outputs. That would include energy, so presumably there would be no way of detecting an isolated system. Stephen Hawking has famously determined that black holes can release information; they are, therefore, not totally isolated systems and may be detectable. Philosophically speaking, that we have supposedly detected their existence must surely imply that they release information…

The idea of open systems was developed last century to accommodate observations that life, civilisations, weather, our Sun, indeed everything that we observe does not, de facto, appear to increase its entropy with time. It is not so much that the Second Law is wrong; more that it does not apply. Instead of increasing entropy, we see entropic life-cycles, as systems form (reducing entropy), mature, age and decay/collapse in an entropic outburst. The many parts subsequently come together with other parts to form new systems and the energy-driven cycle repeats endlessly. This entropic cycling appears everywhere we look in the real world about, below and above us.

A mental model might consider a submerged pump pushing water upwards to the surface of a pond. The up-thrust causes vortices, whorls and ridges to form on the surface in close analogy to a weather/entropy map. The patterns fade towards the edge of the pond, being replaced in a continuous process by newly formed patterns emerging from the centre. I.e., energy causes entropy to reduce/open systems to form, as evidenced by these dynamically stable, yet short-lived, patterns in the water. Some patterns coalesce, either combining their energies or disappearing. Other patterns fade as their energy dissipates into the surrounding water. More energy from the pump results in more larger, deeper patterns, each with more energy and therefore tending to last longer and spread out further before eventually dissipating.


Notional Entropy Surface Map. Systems appear as dents in the fabric of entropy

Open systems are formed of interacting, often-complementary, parts. Interactions between the parts sustain each other by the exchange of energy, substance and information. The whole is therefore internally dynamic, and work is done (energy dissipated) to maintain the reduction in local entropy.

An open system can be dynamically stable, provided the mean inflow equals the mean outflow over some arbitrary period. As a consequence, open system stability occurs, not at low energy, but at relatively high energy levels. This view of open systems starts to rationalise some observed phenomena with which some physicists may be uncomfortable. For instance, weak chaos is observed when a restricted flow is resisted, as may be the case in the interchange between parts.

The classic example is the sand pile that has grains of sand added to it's rising peak. The peak rises to a critical height, at which avalanches occur, many small, fewer larger, always restoring the pile towards its critical value. This phenomenon of so-called weak chaos, coupled with self-organized criticality, is observed in many situations: earthquakes, cometary fragments entering Earth's atmosphere, distances between cars on motorways, stock exchange prices, thermal noise in conductors, crime statistics, and many more. Invariably, it seems to arise at the interface between open systems.

The graph at right shows the kind of (simulated) behaviour engendered by dynamic interchanges between the parts of a system. The tiny oscillations above and below the mean line of the graph are caused by the weakly chaotic interchanges between the parts. Overall, the system has risen from a relatively small extent/mass/volume/energy to reach a dynamically stable plateau at a high energy level and low entropy. 

Actually, we are all intimately familiar with this kind of behaviour. If we think about our own bodies, they are open systems made up from a variety of complementary interacting parts. Our weight may appear stable, for instance, but if we were to examine it closely, we would see that it rose and fell by the hour, the day, the month and the year. Even when we rest, our internal parts continue to interact in a frenzy of activity, with the cardiovascular system bathing other partsand itself—in blood, the immune system seeking out and neutralising pathogens, and so on. Many of the interchanges taking place between parts in our bodies are irregular and some may be weakly chaotic. 

Another aspect of open systems that may disconcert is chaos. Not so-called weak chaos just described, but deterministic chaos. Chaotic behaviour is interesting; it is not random, and it is not unconfined. It does seem, however, to be unpredictable except insofar as it is bounded. Interacting open systems can behave chaotically in that the interchanges between the parts can, but need not, result in irregular periods of relative calm interspersed with irregular periods of frenetic activity. 


This graph of entropic cycling derives from a simulation of archetypal open, interacting systems; this kind of behaviour, with plateaux interspersed with unexpected change, seems to be typical of close-coupled open systems. Note the pattern of build-up and sudden collapse, repeated continually, but never in quite the same way. With open systems, weak chaos, self-organized criticality, chaos, catastrophe, open systems and so on, we might be forgiven for wondering if there is a different kind of physics at work both in the heavens and here in the real world; a physics of open systems, perhaps with a Law of Entropic Cycling. Observation would suggest that there might, indeed be such a law, which might be tentatively stated as follows: 

Energy forms/sustains open, energetic, interacting systems, which dissipate energy over time to maintain themselves.

Like the Second Law of Thermodynamics, this putative, empirical law demands some qualification:

  • Work is done to create/configure open systems
  • Open systems are "entropic wells" of energy; the more energy, the deeper the well.
  • Work is done/energy dissipated, to maintain order within an open system
  • The lifetime of an open system increases with its potential energy/depth of entropic well, and reduces with its rate of energy dissipation.
  • Open systems can exchange energy
  • Groups of open systems may mutually sustain each other by exchanging energy

What can we make of these ideas of open systems and entropic cycling? Our Sun has radiant energy at the centre and some three concentric zones of convection near the outer surface. So, the Sun is self-organized, it comprises a number of dynamic, interacting systems which do work/expend energy in maintaining themselves, and the whole is driven by fusion energy which dissipates into the space around the Sun. 

It is possible to see parallels between galaxies and weather patterns here on Earth. Elliptical galaxies, for instance, resemble the isobar patterns of cyclones marked on weather maps. Like galaxies, cyclones and other weather features represent a reduction in entropy as evidenced by their regular patterns. 

Weather systems self organise to stretch continuously around the world, driven by energy from the Sun and the Earth's rotation, configured around and above seas and landmasses. Moreover, the various structures within the overall weather system, what we might call the weather subsystems, mutually interact in a complex, even chaotic, way. While there may be arguments about the cause, it seems that the mean surface temperature of Planet Earth is rising at present. Weather patterns are changing. Storms are becoming more severe, rainfall heavier, periods of sunshine hotter and more prolonged. Overall, is this an increase in entropy, or a decrease? 

As the real world in which we live is made up from networks of interacting systems; economic, political, environmental, ecological, social, etc. - the Law of Entropic Cycling should be universally applicable. The value of any law lies in its ability to make predictions. In this case, we could make predictions about the weather, as it will be affected by global warming. The prediction would be directly analogous to the pond model above. The energy of global weather systems will increase, as will the rate of energy dissipation, and the degree of interaction between weather systems. With more energy in the atmosphere, there will be more weather features such as cyclones and anti-cyclones, troughs and fronts. These will be more intense and will endure for longer, before fading and being replaced, degrading their energy as they do so. So, overall, weather will be more changeable, there will be more lows and more highs, the lows will be lower, and the highs higher. 

The thought does arise, however: what if global temperatures are changing, as part of some continual entropic cycle in the interactive network of Earth's many systems? Or perhaps there is a continual cycle between the Sun and its planets, including Earth, which we currently detect as rising global temperatures. Such notions raise different spectres. Perhaps we humans are not, after all, the cause of global warming, any more than we caused the last Ice Age. If so, then should we not be preparing to survive in a changing world rather than trying to prevent that inevitable change? 

So, what is happening to encourage the formation of infant stars in that “new” galaxy? Is that region open, receiving unseen energy and substance from other regions? Are gravitational waves, perhaps, making local dark matter clump as in a galactic-scale Kundt's tube or Chladni's plate experiment? Is new material being spewed into that region of space through a wormhole connected to some distant black hole? Are we glimpsing a rift in some multi-verse? However exotic the explanation, it seems reasonable to suppose that the new star formations are not an isolated system, vis-à-vis the Second Law of Thermodynamics. 

One way to look at such a star grouping is to consider the star group as a system, made up from dynamic, interacting stellar subsystems, together with indeterminate interstellar material. This is redolent of the organismic analogy, i.e., that the star group is made up from separate parts which act together as a unified whole, bound together by gravity, and exchanging energy and substance. The whole has a life-cycle, which it has just started. It will develop, evolve, mature and eventually decay/collapse. If the Law of Entropic Cycling is to be believed, however, then what we could be seeing in this new galactic nursery may be not so much a totally new system, but a resurgence, another phase in a never-ending cycle of birth, death and, in this case, rebirth. 

Not so much a Big Bang, perhaps; more a continuous Universe?