Entropy as an engine of life’s origins

by Rich Feldenberg:

In our last Darwin’s Kidneys post we discussed the basic concept behind the second law of thermodynamics, which requires that entropy increase for every irreversible process. Entropy can be thought of as the amount of disorder in a system, so this law is essentially saying that there is an increase in the total amount of disorder that accompanies every physical process. We discussed why this law – which is thought to always hold true throughout time and space – does not prohibit the development of complex structure or the evolution of life, but it might also be true that the second law is a driving force behind the evolution of complexity in both living and non-living systems.

In this article I would like to continue our thermodynamic discussion, but introducing an interesting, although somewhat unproven and controversial offshoot of this scientific principle, which attempts to show that self organization of atoms and molecules is actually a consequence of second law dynamics. It’s founder and major proponent is a young physics professor at MIT, named Jeremy England. He has been attempting to show through a rigorous mathematical approach, that complexity arises naturally in physical systems as these systems move towards more efficient mechanisms to disperse energy – increase disorder in their surroundings. These systems become more efficient at increasing universal disorder, by becoming themselves more ordered. This work has potentially broad implications helping us understand how living systems might have arisen naturally from non-living systems, even before those systems were self-replicating and capable of Darwinian evolution.

The entropy of a closed system will always increase over time, but an open system allows an influx of energy so that the entropy of part of that system can decrease as the entropy of it’s surroundings increases. The geochemical environment of the early earth could be considered an open system because there was intense energy continuously entering into the system from the sun. Plants are extremely efficient at using that energetic sunlight to maximize the disorder of their surroundings. This is somewhat like looking at the problem upside down from our usual way of thinking. We normally think of plants evolving to use sunlight more effectively to become more complex, and as a natural consequence they create a larger entropy to the environment. England’s way of looking at the plant might be to say that second law demands that entropy will increase with time and the highly energetic sunlight will affect the system so that complexity will arise that will move towards maximum entropy generation. Those more effective entropy generators will necessarily be more complex systems, tending toward self-assembly and reproduction, and in some cases, eventually what we would recognize as living things. Living systems are very good at dissipating its energy.

 

For these kind of processes to occur a system has to be out of thermodynamic equilibrium. At equilibrium there is no net energy transfer, but a system out of equilibrium has a net movement of energy – the influx of sunlight, for example. At some distant time in the future, the entropy of the entire universe will be high (the universe being a closed system), and at that point all areas of the universe will be in thermodynamic equilibrium, and complexity, organization, and life will cease to exist. Fortunately, it is likely to be a very long time before that fate befalls our universe.

England’s thermodynamic dissipative process might explain organized non-living structures we see everywhere in the world, from the formation of snowflakes and sand dunes, to planetary rings and spiral galaxies. These structures preferentially form to better disperse energy into more disordered and less usable forms – a consequence of thermodynamic’s second law. In this way, life itself is just one form of a more broad variation on this theme. Self organizing structures may have formed to raise entropy maximally, and in doing so lead to the first self-replicators. Once you have replicators, a Darwinian evolution by natural selection can take over to increase complexity further.

Not all researchers believe that Dr. England’s theory will pan out as a solution to the origin of life, but it seems that there are more than a few that have been impressed with the theory and its results so far. I have read two of England’s original journal articles, and unfortunately that math of the statistical mechanics was beyond me. From what other researchers have said, however, the equations used are valid, it is their interpretation for self assembly and origins of life, that is still unclear.

Professor England is himself and interesting individual. In his early 30s and approaching the origin of life field from a fresh perspective, England earned his PhD in physics at Stanford University in 2009, and is now an Assistant Professor of Physics at the Massachusetts Institute of Technology with his own research lab. In 2011 he was named as “one of the 30 under 30 rising stars in science”, by Forbes magazine. One thing that I found particularly fascinating is that although England is attempting to crack the tough nut of the origins of life, using sound science and mathematical modeling, he is a devout Orthodox Jew. He speaks somewhat to his faith and how he reconciles faith with his naturalistic scientific approach to answer this basic fundamental question, of interest to both science and religion, in his podcast interview that I linked to below. Faith and high level scientific inquiry may be a good topic for another time.

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I look forward to following Dr. England’s future work, and watching if others pick up on it and extend it further. If England is right, then far from The Second Law of Thermodynamics being a repressor of complexity, it may more accurately be a driving engine of the spontaneous production of organization and complex systems.

 

References:
1. “Statistical physics of self-replication”, Jeremy L. England; The Journal of Chemical Physics. 139, 121923 (2013).
2. “Dissipative adaptation in driven self-assembly”, J.L. England; Nat Nanotechnol. 10(11):919-23, Nov 4, 2015.
3. “The New Physics Theory of Life”. Quanta Magazine. January 22, 2014.
https://www.quantamagazine.org/20140122-a-new-physics-theory-of-life/
4. “Origins of Life: A Means to a Thermodynamically Favorable End?” Yale Scientific. July 1, 2014.
http://www.yalescientific.org/2014/07/origins-of-life-a-means-to-a-thermodynamically-favorable-end/
5. The 7th Avenue Project (Podcast). “Biophysicist Jeremy England: A New Theory of Life”. May 3, 2015.
http://7thavenueproject.com/post/118064180870/biophysicist-jeremy-england-new-theory-of-life
6. “How can we be so complex if the second law of thermodynamics is true?” Darwin’s Kidneys. Dec. 4, 2015.
http://darwinskidneys-science.com/2015/12/04/how-can-we-be-so-complex-if-the-second-law-of-thermodynamics-is-true/

 

How can we be so complex if the second law of thermodynamics is true?

By Rich Feldenberg:

There is no doubt that physics is a difficult subject to master, but there seem to be particular areas of physics that are commonly misunderstood and misapplied by the general public. One such area is quantum mechanics – a field within, so called, modern physics – where complex mathematical structures provides hints of the underlying nature of the universe that are completely counter intuitive to our “common sense” notions of how things should be. Another area of physics that falls into this category of being frequently misunderstood is thermodynamics – specifically the second law of thermodynamics – a field coming out of classical physics that deals with the notion of changes in entropy of physical systems. This article will focus on that second area – the second law of thermodynamics.

 

Thermodynamics originated in the 17th century, as a way to understand heat, energy, and work. Over time there came to be four laws of thermodynamics described and labeled as laws zero through three. The zeroth law relates the fact that if object A is in thermodynamic equilibrium with both objects B and C (meaning that there is no net heat exchange between them), then it follows that B and C are also in thermodynamic equilibrium with each other. Maxwell concluded from this observation that, “all heat is of the same kind”. We understand this effect when we take a temperature measurement with a thermometer. Once the thermometer is in thermodynamic equilibrium with the object of interest (there is no net heat exchange) the temperature of the thermometer will give you the temperature of the object being measured. A perfect thermometer will not change the temperature of the object in question.

 

The first law of thermodynamics is a conservation law, and simply put says that energy is a conserved property. The energy in a closed system is fixed, or constant, and while the energy can change form (i.e.. Could change from thermal to mechanical, kinetic, electromagnetic, gravitational, or so on) the amount of energy stays entirely the same, always and forever. The only processes that are allowable are those in which the total energy of a closed system is constant. This law lets us know which process can occur. If a process would require a change in the total energy of a closed system, then that process is forbidden by nature.

 

The third law of thermodynamics provides us with the simple statement that ‘the entropy of a perfect crystal at absolute zero temperature is zero’.   We’ll define entropy in a moment, once we get to the second law of thermodynamics, but we’ll just remark that absolute zero is the lowest temperature theoretically possible, and that if you ignore the effects of quantum mechanics where neither the momentum and position of a particle can both be known with perfect precision then in a classical system an object is in its lowest energy state at absolute zero, thereby removing any disorder in the system. This law also indirectly implies that it can never be possible to reach absolute zero through any means.

 

We won’t comment further on thermodynamic laws zero, one, or three in this article, but will move onto the second law of thermodynamics. The second law governs which types of process are spontaneous – will occur without the input of energy from the outside. The second law states that the entropy of a system as a whole, must increase for any spontaneous or irreversible process. For a reversible process the entropy could remain constant, which is also allowed by the second law. Entropy (given the symbol: S ) can be described as the amount of disorder in a system. For a system to increase its entropy, the system must become more disordered. This is not to say that certain subparts within the system might not become more orderly (i.e. Decrease their entropy), but they would do so at the expense of the system as a whole, which if you added all the contributions to ‘change in entropy’ together (the pluses and the minuses) you would find that the sum is always a plus (entropy has increased). This does not prohibit complex, and very ordered, systems to develop, but they do so because they are increasing entropy even more is some other part of the universe.

 

If the second law really forbid anything becoming more ordered or complex then we would be breaking the second law of thermodynamics every time you made your bed, cleaned the living room, baked a cake, or put together a lego model. When we use a refrigerator to cool the temperature in the freezer we are decreasing the entropy inside the fridge. Even the ancients were skilled at producing order when they built the pyramids out of clay and stone, mined and separated metal ore from the earth, and grew crops. To the uninitiated, all these things, at least on the surface, would seem to break the second law of thermodynamics. But, we know the second law can not be broken, at least no one has ever seen an example of an exception to the rule yet.

 

As impressive as these examples of technology to increase complexity are, they pale in comparison to the complexity of a living system. Look at how complex, orderly, and precisely organized is a living cell. Even a lowly bacteria is a little pocket of highly organized molecular structures, far out of thermal and chemical equilibrium with its environment (one requirement for life, even if not a complete definition). The cell has a very improbable structure, based on random chance alone – that the atoms of the cell would randomly assemble based on thermal motion into the complex set of protein, nucleic acids, and so forth – but we’ll see that it was not random chance that lead to living cells. A cell functions as a living thing precisely because its entropy is so low. So how could such a thing exist in a universe where the second law of thermodynamics is in effect? If entropy (disorder) has to increase, then how can there be even the simplest of cell types?

 

Well, the complex and organized structure of the living cell, can be generated when it creates an even greater amount of disorder in its surroundings. The heat generated by metabolism is transferred to the surroundings where it loses its potential to do useful work. The power supplied by the sun to run nearly all ecosystems, provides energy that can be harnessed by living things to keep their entropy low, and stay far from equilibrium with their surroundings. If the sun went out, that supply of energy would be cut off, and without a continuous supply of renewed energy being delivered, entropy of the ecosystem would certainly increase as organism die, losing order as their molecular parts are dispersed. The sun itself, the power supply, has a low entropy due to its dense structure of hydrogen, and is increasing the entropy of the universe as it fuses hydrogen to helium, releasing less orderly radiation and neutrinos out into space. It’s taking a nice condensed ball of hydrogen gas and producing a sea of radiation spreading out in all direction in space – in other words, it’s making a real mess of things! The entropy of the universe is ever increasing, as a consequence all the processes, both living and non-living, that the universe is so good at performing.

 

The total amount of energy in the universe remains unchanged throughout time (first law), but that energy becomes less and less usable due to the increasing entropy (second law).   The quality of that energy (how useful it is at doing work) does change, and the quality of universal energy is worsening as time goes on. In fact, it is entropy which seems to provide some sense of which way time is flowing, what some call an arrow of time. The difference between past and future is not the amount of energy in the universe (which is constant) but in which direction the disorder is higher. The past, always more ordered and the future always more disordered. This increasing disorder is a natural consequence of the number of micro-states a system has. What we mean by this is simply that, if you imagine say a container filled with helium gas (this is our closed system) each helium atom can occupy any particular point in the box, so long as there is not already another helium atom taking that spot. Even in a small box, there could be a very large number of helium atoms – atoms being so tiny, and a mere 4 grams of helium would contain 6.02×10^23 atoms – a truly astronomical number. If you consider where each helium atom is in the box at some given time, that is one micro-state. The atoms will have some thermal energy and will be moving in random directions, bouncing off the walls of the box and off each other, so at some other time each atom will be in some new location. This would be a new and completely different micro-state, but it is likely that both micro-state will look essentially indistinguishable – both appear to us just as completely random mix of helium atoms. That is they will have basically the same macro-state because there would be no way to tell the different micro-states.

 

Now a micro-state could appear different, however, if all the helium atoms suddenly moved to one corner of the box and left the remains areas an empty vacuum, or if they all huddled together into the shape of a little arrow in the middle of the box. There is nothing saying that such micro-states are impossible, it is just that with the huge number of micro-states available, those with random appearing properties will far out number the few states with non-random appearing properties. The non-random appearing states really are just random, but they are going to be very unlikely to occur, just by statistics alone. There will be many many micro-states where all the atoms look randomly distributed in space, and in comparison, really few micro-states where the atoms look non-randomly spaced. It’s just a statistical argument, nothing more.

 

So how can order be increased (entropy decreased) so that things like living things can be alive, evolution can take place, and so forth? We could force all the atoms in our box to reside in one small corner, but it would involve work being done on the system. This would lead to an increase in entropy somewhere else.   For example, we could have a piston in the box, and push the piston down causing the helium atoms to move closer to the corner, making the gas more dense, and decreasing the entropy in the box. In order to do this energy has to be supplied to the piston. This will mean that some of the energy used to drive the piston must be wasted as heat (it is thermodynamically impossible for the energy efficiency of the piston, or any machine, to be 100%) and leading to increased entropy.

 

Living systems are able to harness energy from their environment to remain in their low entropy ‘alive’ state. That energy may come directly from the sun to run the process of photosynthesis, or could be chemical energy derived from high energy chemical bonds in biomolecules consumed by animals, for instance. As stated before, the low entropy state of the living system remains highly ordered at the expense of an even greater increase in entropy of the universe.

 

Creationists have been known to invoke the second law of thermodynamics as a way to show that evolution breaks the laws of physics, but this only really reveals the creationists lack of understanding of the second law. One consequence of evolution is that over geological time the complexity of organisms has increased. That is not the “goal” of evolution, who’s only objective is to pass genes on to the next generation, but in the process of producing more efficient gene passing devices (i.e. Organisms that survive and reproduce more effectively in their environment) some will have proceeded down a road of increased complexity (keep in mind that many remain simple if they can find other ways of remaining good reproducers, in fact, some may even regress as parasitic worms have which no longer need much more than a gut and reproductive tract to be successful).   The second law does not forbid evolution or the evolution of increasing complexity. Organisms in the process of survival, reproduction, natural selection are simply taking the energy stored from sunlight and using in a multitude of different ways. The universe at large pays the price for all the things living things do, including evolving, by increasing its overall entropy.

 

We know that the entropy in the universe today is more than it was yesterday, and less than it will be tomorrow. If we extend this line of reasoning to the universal extremes then it stands to reason that entropy was at its minimum at the beginnings of the universe and will be at its maximum at the end of the universe (if there is such a thing). The Big Bang was a very orderly state when you consider that all energy was packed into a tiny subatomic space. What about our cosmic destiny? Most cosmologist believe the evidence shows that the universe will continue to expand forever, and entropy will eventually reach a maximum. At that point there will be no further processes or reactions (whether chemical or nuclear) that will occur. This is called the ‘heat death’ of the universe, as there can be no net heat transfer, and hence no way to increase entropy further. When this happens there will be no more stars or living things, just a sea of ever diluted radiation, as space-time continues to expand.

 

The second law is fundamental to our understanding of how things work. It also explains why some things can never be possible – like perpetual motion machines which never lose heat energy to their surroundings – impossible! It makes sense when you begin to understand it as a consequence of what is happening on a microscopic scale. It is certainly not an argument against complexity arising, but it does tell us that all complex systems have a universal cost that has to be paid.   As long as we have a ready source of incoming power – the sun in our case – things can continue to remain ordered for billions of years. That’s good news for us who have no choice but to obey the law!

 

If Block Time is True then Heaven and Hell are both real, and you’re in both of them right now!

By Rich Feldenberg

For what is perhaps the most familiar and everyday of the physical properties, time has remained a highly perplexing mystery to physicists. Our minds evolved to have a sense of the passage of time. Perhaps the only other physical property so intuitively familiar to us is that of matter itself. Having a mental construct of the world where there is a passage of time, and where things have shape and solidity, had it’s obvious survival advantages to a clever young primate species first becoming self aware on the African savannah. There was no selective pressure for us to have any intuitive sense about quantum mechanics or general relativity since these phenomena could not be sensed by our evolving minds.

This makes it seem to us, as though we are born with an intuitive knowledge of what time and matter really are. We have a common sense about them, but our innate understanding of such things doesn’t necessarily correlate with a true understanding. Our sense of physical law evolved to be useful, but there was no reason it needed to evolve to be accurate. In fact, we know that modern science tells us that solid matter is anything but solid. It is composed of tiny atoms that are themselves made of nearly entirely empty space. Electromagnetic forces of repulsion between electrons in the atoms of a wall, and those of your body, give to us the illusion of solidity, and make any attempt to walk through the wall very painful.

The same is likely to be true about time. Despite how many times we look at our watches each day, we really don’t get it. At the subatomic scale time doesn’t seem to have much meaning. If you observe two elementary particles interacting, you wouldn’t be able to tell if you were being shown the interaction in forward or reverse. The laws of physics do not differentiate a forward or backward flow of time at this tiny scale. It is only when we start to observe very large collections of particles on the macroscopic scale that there appears to be an arrow of time – a particular direction to flow. You could tell the direction of a movie if it showed an egg breaking on the floor. We know broken eggs don’t just fly together and become unbroken.

This is due to the effect of entropy, which is simply a measure of the statistical likelihood of how a system will change. While there can be local decreased in entropy, the overall net effect is one of increasing entropy, and this leads to our conception of an arrow to the direction of time. One way of looking at it is by considering a large collection of gas atoms. Lets say helium atoms confined to a gas cylinder. There are very few ways that the helium atoms can be arranged in an orderly way. If they are all packed together down at the bottom of the cylinder, or they are all forming a sphere in the middle, or arranged into the letters “He” (for helium), towards the top of the cylinder, and so on. There is nothing saying they can’t do that, but it is statistically very unlikely. It is much more likely that the helium atoms are arranged basically randomly throughout the cylinder. That is because there are so many more ways the atoms can be arranged in a disorderly random state, than in one of the few orderly states. From the macroscopic view, the many states where the gas in the cylinder appears disorderly all look the same. They actually aren’t the same, all the atoms could have been in the exact opposite site of the cylinder from where they actually were, but to us it would still look the same. It is this movement towards a more disorderly state, the increase in entropy, that seems to suggest an arrow of time at larger scales.

Well, some physicists now feel that the passage of time is an illusion altogether, and that instead the universe exists in something called block time. In a block time kind of universe the entire universe, from beginning to end, is always in existence. Everything in the past is just as real as everything happening right now in the present. Even more incredible, everything in the future is just as real as this moment you are experiencing right now. There is no difference between past, present, and future, if block time is correct. This view is also called untensed and, as such there is no privileged point of view in time.

This is obviously counter to our common sense view where the present has the only privileged status and is constantly flowing. Now is real, but wait, that point in time is now gone and we can never get it back. Now is dead, long live the now! This kind of view, the way our natural intuition feels most comfortable is called Presentism. But as I’ve said, common sense isn’t necessary leading us to truth. The Caltech theoretical physicist Sean Carroll, who has written several popular physics books including, “From Eternity to Here” and “The Particle at the End of the Universe”, says that he finds the block time concept, “perfectly acceptable”. It is far from settled whether this is the best description of the universe and is still being debated in theoretical physics circles, but if true would seem to have some amazing philosophical implications.

For one, this would seem to imply a kind of immortality. Our life is just a tiny line in the cosmic loaf of block time (I like to picture it like a loaf of bread with a thin slice as being everything we think of as the present moment). Of course, the whole idea of block time is that the entire loaf of bread (past, present, and future universe) is all right there, so our tiny time line always exists. Maybe that would explain why you and I feel alive at this very moment even though our lives are likely to be only a century or so out of the hundreds of trillions of years that the universe is likely to exist. It would seem very unlikely that the universe should be in that very special time right now when we are alive. I mean shouldn’t it be much more likely that the universe should be somewhere in the next trillion years than in here at 13.7 billion years since the big bang? The usual answer would probably be to simply invoke the fact that if the universe wasn’t at this point then we just simply wouldn’t be here to wonder about it. That might be just fine, but it is still statistically an astronomically unlikely coincidence.

Ok well, lets just run with the block time thing for a second here. Every moment in time is just as real as every other. What ever is going to happen in 100 trillion years from now is just as real as what is happening now as I type this sentence. Oh, and by the way, you and I are long dead and forgotten in that slice of the bread 100 trillion years down the road. But we will continue to live in our limited slices of the loaf forever. I’m always experiencing this very moment, and the moment that I was born, and the moment I died, and every other moment of my life. In that sense we are immortal in the block time universe.

If so, then that makes heaven and hell completely real too, in that you and I are in them both, always and forever. I don’t mean that heaven and hell exist in another dimension or have a supernatural existence. All I mean to say is that we all have moments in our lives where we feel great joy and happiness, even if it is very momentary. And likewise there are moments where we are deeply hurting and in pain -again they may be very short periods, but yeah, they can be pretty bad. That “us” that is experiencing the moment of joy, happiness, or pleasure is basically always in a kind of heaven. Unfortunately, that “us” in those moments of pain, hurt, depression, worry, fear, or despair is also always in a kind of hell. The majority of our lives are somewhere between the peaks and troughs, in the just “business as usual” sort of mundane life events. Forever in front of the TV, climbing the stairs, brushing our teeth, looking for something to eat in the fridge, and of course sleeping in non-dream sleep.

Block time also challenges our ideas about free will. In a block time universe, everything is already destined to happen in a certain way. The future is just as unchangeable as is the past. We simply have the illusion of free will, but there is zero chance that we are going to do anything other than what is already engrained into the block time universe. The question of free will is one that philosophers have been discussing for centuries, long before the concept of block time entered the theoretical physics arena. Philosophers might use the word volition instead of free will. Can we have volition and still have a deterministic universe? We may have the illusion of making choice, but the outcome has always been in existence in block time. It would seem a bit like watching an old familiar movie. The characters seem convincing in their parts, their emotion, reactions to events, and so on, but you already know everything that is going to happen and nothing will change the course of events in the film.

It’s unclear if the block time concept of the universe can be proven, or if it is even falsifiable, but certainly the philosophical implications of such an existence seem fascinating. Perhaps our lives really are both eternal and finite. In any case, making the most of this existence would seem to be important. Maximizing the ups and minimizing the downs, and doing so for others as well would seem important if we, and they, are always alive in the moment. Perhaps our fates are already decided, but who’s to say that our intentions are not what sealed those fates to begin with. I’m suddenly reminded by a scene in “The Hitchhikers Guide to the Galaxy”, where a bowl of petunias is suddenly called in to existence miles above the legendary planet of Magrathia. And as it is falling towards the ground, about to be smashed to bits, the thought, “Oh no not again” runs through its mind. The narrator says, “Many people believe that if we knew exactly why the bowl of petunias thought that, we would know a lot more about the universe than we do today”.