Friday, January 24, 2014

A New Theory of Life?

Jeremy England,a physicist at MIT, has a new concept of the origin of life:
Why does life exist?
Popular hypotheses credit a primordial soup, a bolt of lightning and a colossal stroke of luck. But if a provocative new theory is correct, luck may have little to do with it. Instead, according to the physicist proposing the idea, the origin and subsequent evolution of life follow from the fundamental laws of nature and “should be as unsurprising as rocks rolling downhill.”
From the standpoint of physics, there is one essential difference between living things and inanimate clumps of carbon atoms: The former tend to be much better at capturing energy from their environment and dissipating that energy as heat. Jeremy England, a 31-year-old assistant professor at the Massachusetts Institute of Technology, has derived a mathematical formula that he believes explains this capacity. The formula, based on established physics, indicates that when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life.....

At the heart of England’s idea is the second law of thermodynamics, also known as the law of increasing entropy or the “arrow of time.” Hot things cool down, gas diffuses through air, eggs scramble but never spontaneously unscramble; in short, energy tends to disperse or spread out as time progresses. Entropy is a measure of this tendency, quantifying how dispersed the energy is among the particles in a system, and how diffuse those particles are throughout space. It increases as a simple matter of probability: There are more ways for energy to be spread out than for it to be concentrated. Thus, as particles in a system move around and interact, they will, through sheer chance, tend to adopt configurations in which the energy is spread out. Eventually, the system arrives at a state of maximum entropy called “thermodynamic equilibrium,” in which energy is uniformly distributed. A cup of coffee and the room it sits in become the same temperature, for example. As long as the cup and the room are left alone, this process is irreversible. The coffee never spontaneously heats up again because the odds are overwhelmingly stacked against so much of the room’s energy randomly concentrating in its atoms.
Although entropy must increase over time in an isolated or “closed” system, an “open” system can keep its entropy low — that is, divide energy unevenly among its atoms — by greatly increasing the entropy of its surroundings. In his influential 1944 monograph “What Is Life?” the eminent quantum physicist Erwin Schrödinger argued that this is what living things must do. A plant, for example, absorbs extremely energetic sunlight, uses it to build sugars, and ejects infrared light, a much less concentrated form of energy. The overall entropy of the universe increases during photosynthesis as the sunlight dissipates, even as the plant prevents itself from decaying by maintaining an orderly internal structure.
This is way beyond me, but it is rather intriguing.  I don't really have anything to add on the subject, but the reference to the second law of thermodynamics brings back a college memory.  I remember that when I was in college, there was a campus-wide discussion about how Catholic a Catholic university ought to be.  As part of that conversation, our thermodynamics professor required us to compose an essay on the subject of whether the second law of thermodynamics was compatible with the belief in the existence of God.  I have no idea what I wrote at the time, but I'm sure I made the case that they could co-exist rationally.  I'm sure it was a tremendously weak argument.

Actually, even though I don't remember almost any details of the classwork, I do have a couple of other fairly strong memories of the class.  In order to stand out as an individual in a sea of strangers, I wore free seed and chemical company hats throughout my college years.  One day in class, I was sporting my Pioneer seed corn hat, and walked down to the front of the lecture hall to turn in my homework.  The teacher asked me if I was a farmer, and I told him I was.  He asked where I was from, and what kind of a farm I was from.  I told him, and he told me that he grew up on a farm in central Illinois prior to attending U of I.  To put into perspective how much I put into my education, and socialization with my professors, this was one of the most in-depth conversations I ever had with one of my teachers (another was when I ran into my geotech professor in the liquor section at Osco about an hour after my final exam, and when he asked what I was doing, I told him the truth, I was buying my grandparents' Christmas presents.  He laughed heartily, and then I said, no, really). 

The other memory was near the end of the semester.  We were working on thermodynamic power cycles, and were given three homework problems worth 20 points a piece.  In each one, I would draw the proper diagram (see below), and fill in the known state at each point.  I'd then scratch around for a little bit, and realize I didn't really know how to solve the problem.

To make matters more challenging, I had Spring Fever, it was Must See TV Thursday, and I'm sure there was some Schlitz being kept icy cold in the fridge, so I could observe the practical application of the Carnot cycle.  To wrap up my assignment and detail why I didn't solve the problems, I wrote out an explanation that went something like this:
The motion of these cycles has given me a headache and made me sick to my stomach.  Due to these maladies, I need to lie down and rest, and am unable to complete the assignment.  I really hope that the condition will pass before the date of the exam. 
When I got the assignment back after grading, I found that I was rewarded 1 point for drawing out the cycle diagrams and labeling the conditions at each point.  I was awarded 2 points for my explanation of why I couldn't complete the assignment, for a total score of 3 out of 60.  That was the 5% assignment grade I was most proud of in college.

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