Gonzalez and Richards Chapter Ten

Assumptions and implications are not the same thing

Chapter Ten, of The Privileged Planet is entitled, “A Universe Fine-Tuned for Life and Discovery.” 

I suppose one need not be addicted to the SciFi channel to wonder what it would be like to do the “time travel” thing.  We have probably all said, “I’d have liked to be a bug on the wall when . . . ”  or something similar.  We would like to go back and see how things happened because, well, all history is somewhat “revisionist”: selective observation, selective interpretation, selective evaluation, selective synthesis. . . .  We would like to see it for ourselves.  Following on the character Q from Star Trek, Gonzalez and Richards follow an allegory of beings on the Q continuum as they go back “to the beginning” and observe how things were put in motion that allowed, if not dictated, how things would appear as we observe them today (pp. 195-6).  Q takes us back and shows us a machine that set everything in motion in the Universe.  It has calibrations for such things as: Mass Density, Age of the Universe, expansion Rate of the Universe, Speed of Light, Weak Nuclear Force, strong Nuclear Force, Proton to Electron Mass ratio, Gravitation Force, Cosmological Constant, and Electromagnetic Force.  The question arises then, how precisely do these items on the machine have to be set?  Q and his compadres have not found any setting but the one presently on the machine – that will not exterminate life in the Universe!

The authors then illustrate the “large number coincidences,” or “anthropic coincidences” with the case of gravity:

If gravity were slightly weaker, the expansion after the Big Bang would have dispersed matter too rapidly, preventing the formation of galaxies, planets, and astronomers.  If it were slightly stronger, the universe would have collapsed in on itself, retreating into oblivion like the groundhog returning to his hole on a wintry day.  In either case, the universe would not be compatible with the sort of stable, ordered complexity required by living organisms (p. 197). 

Of course, none of this happens in isolation.  There are relationships between gravity and the strong nuclear force – and it must be fairly precise and stable for complex life to develop and exist.  Randomness simply doesn’t explain the luck of the draw when it comes to looking around us and evaluating existence.  “Thrown to the winds of chance, an uninhabitable universe is an astronomically more likely state of affairs” (p. 197). 

First, the authors examine “Fine-Tuning in Chemistry.”  It has long been suggested that life as we know it must be somehow based on Carbon, Hydrogen and Oxygen.  And the reciprocal relationship between complexity and measurability seems exemplified in the development of Chemistry as a science:

Throughout the nineteenth and much of the twentieth centuries, chemists spent most of their time working on reactions in aqueous solutions.  If water could not dissolve such a broad range of substances, chemistry would have developed at a snail’s pace, perhaps never reaching the status of a science.  Thus, the conditions that make our planet congenial to life have also contributed to the rapid development of chemistry as a science (p. 198). 

Hoyle’s discoveries in respect to the relationship between Carbon and Oxygen are no less stunning.  As a result of the studies of “resonance” in carbon-12 and how carbon (and oxygen) are produced in stellar reactions, we know that there is one more life-friendly fact about the universe.  Because of certain coincidences, we find that stars produce carbon and oxygen in comparable amounts.  If there were more than a 4 percent variation in the carbon-energy resonance it “would yield a universe with either too much carbon compared with oxygen or vice versa, and thus little if any chance for life” (p. 199). 

The authors then go on to discuss the four basic forces: The strong force is what holds protons and neutrons together despite the positive and thus repulsive charge of the protons.  This is one of the many things that helps to synthesize the more heavy elements required by life.  “The more complex organisms require about twenty-seven chemical elements, iodine being the heaviest (with an atomic number of 53).  Instead of ninety-two naturally occurring elements, a universe with a strong force weaker by 50 percent would have contained only about twenty to thirty.  This would eliminate the life-essential elements iron and molybdenum” (p. 201).  An additional consequence of a shorter periodic table would be that lighter isotopes might be radioactive.  We need potassium-40 for plate tectonics; but it must be low enough in radioactivity to avoid the irradiation of life (p. 202). 

The weak-force including electromagnetic force (“these . . . two now often combined into one force called electroweak” [pp. 200-01]), among other things, governs the conversion of protons to neutrons and vice versa as well as the interaction of neutrinos with other particles.  This force comes into play in a supernova.  “This process precipitates the initial collapse, which allows such stars to return their metal-enriched outer layers to the galaxy.  Without it, there would not be enough essential elements available for life” (p. 202).  Changes in the weak force would also change the ratio of helium to other elements.  It also affects stellar luminosity (real brightness) and consequentially how long the star will stay on the main sequence (remember we need Sun-like stars for life as we know it).  “. . . the only property of a star that affects a planet’s orbit is its mass, while the only property of a star that affects a planet’s surface heating is its luminosity” (p. 202).  Helium stars burn out too quickly whereas Hydrogen stars burn more slowly. 

Our hydrogen-burning Sun consumes its nuclear fuel more than one hundred times more slowly than a pure helium star of comparable mass.  A helium star of an appropriate mass wouldn’t last nearly long enough for life to develop.  Not that life would ever develop around such a star anyway: it would contain no water or organic compounds, making the formation of life on any timescale impossible (p. 203). 

The authors then go on to assess gravity and I concur with their sentiments.  “Gravity is the least important force at small scales but the most important at large scales” (203).  My notion is that when they find the “Quantum Theory of Gravity” or the “Theory of Everything,” they will probably find that there is a commonality at the level of the force or energy itself.  At the stellar level, “A star is in a state of temporary balance between gravity and pressure provided by hot gas (which, in turn, depends on the electromagnetic force)” (203).  What happens if you change gravity at this level?  Let’s say you increase it.  It would take much less material to ignite a star; it would burn out much faster; and its luminosity would be much less:

Such a star would be about one-thousandth the luminosity, three times the surface temperature, and one-twentieth the density of the Sun.  For life, such a mini-Sun is a mere “shooting star,” burning too hot and too quickly.  A universe in which gravity was weaker would have the opposite problem (203). 

There is a razor’s edge balance between convective and radiative energy transport within a star.  The balance, again, is the balance between gravity and electromagnetism.  It is necessary for life to have main-sequence yellow stars.  Red stars slow things down; blue stars irradiate things.  Change gravity one way or the other and you get more red or blue stars and reduce the chances of yellow stars with full spectrum light that makes life as we know it possible. 

Increase planetary gravity and you might do nothing to simple life; but you would put a top end on how large creatures could grow without collapsing in on their own weight.  More gravity, more impacts from meteorites and comets (e.g., Jupiter).  Smaller planet?  It would lose its internal heat faster rendering it inert in regard to all the benefits of plate-tectonics. 

Decrease cosmic gravity and things would fly apart before stars and galaxies could form and produce the heavy materials needed for life.  Increase cosmic gravity and things might simply come back together into a gradually increasing number of black holes and destroy any incipient life in mass and radiation.  Coincidentally, or providentially as the case may be, this delicate balance between forces as well as the age of the universe make us able to study the cosmic background radiation and make some of the inferences about our universe that we have. 

At the cosmic level there is the delicate choreography between attractive gravity and repulsive dark or vacuum energy.  “Often called the cosmological constant [not the same as Einstein’s greatest mistake], which is theorized to be the result of a nonzero vacuum energy detectable at cosmological scales, it’s one of the few cosmological parameters that determine the dynamics of the universe as a whole” (p. 205).  Some of this theory was made possible by safe-distance studies of TypeIa supernovae. 

There’s only one “special” time in the history of the universe when the vacuum and matter energy densities are the same, and we’re living very near it.  If the vacuum energy had become prominent a few billion years earlier than it did in our universe, there would have been no galaxies.  If it had overtaken gravity a little earlier still, there would have been no individual stars (p. 205). 

Prior to this, it had been hoped that there was some law of math or physics requiring the value to be 0; but thanks to studies on the Type Ia supernovae, it was discovered that there must be fine-tuning at the particulate level to one part in 10⁵³ at the very least.  “At the same time, its value must be large enough in the early universe to cause the newborn universe to expand exponentially as inflation theory postulates” (p. 205).  And so the dance continues. 

The authors then go on to show that it is not just a matter of fine tuning at the micro- and macro-levels, it is a matter of fine-tuning on multiple levels at once as with the Universe Creating Machine shown us by Q.  Astronomer Trimble words it this way:

The changes in these properties required to produce the dire consequences are often several orders of magnitude, but the constraints are still nontrivial, given the very wide range of numbers involved.  Efforts to avoid one problem by changing several of the constraints at once generally produce some other problem.  Thus we apparently live in a rather delicately balanced universe, from the point of view of hospitality to chemical life (quoted on p. 206). 

Gribbon and Rees similarly state:

If we modify the value of one of the fundamental constants, something invariably goes wrong, leading to a universe that is inhospitable to life as we know it.  When we adjust a second constant in an attempt to fix the problem(s), the result, generally, is to create three new problems for every one that we “solve.”  The conditions in our universe really do seem to be uniquely suitable for life forms like ourselves, and perhaps even for any form of organic chemistry (quoted on pp. 206-7). 

The authors conclude with a chart of the balance of factors and possible worlds (p. 207) and state:

We tend to think of laws and parameters as governing the cosmos in general, but as we’ve seen, changes in these universal variables have profound consequences on particular objects within the universe.  Changes in the relative strengths of gravity and electromagnetism affect not only cosmological processes but also galaxies, stars, and planets.  The strong and weak nuclear forces determine the composition of the universe and, thus, the properties of galaxies, stars, and planets.  As a result, we ultimately can’t divorce the chemistry of life from planetary geophysics or stellar astrophysics (pp. 207-8). 

The second half of the chapter is about how the same effects that permit life also facilitate discovery.  The authors begin with about four things pertaining to Carbon and Oxygen.  First, water has facilitated studies in chemistry and advancements in high technology (p. 209).  Secondly, the authors claim that carbon-14 helps us to date things that were once living.  Third, an oxygen-rich atmosphere makes it transparent to light allowing us to explore not only the neighborhood, but the distant universe as well.  And fourth, “. . . the carbon monoxide molecule (CO), with one carbon and one oxygen atom, is the best tracer of dense molecular gas in the interstellar medium and around young stars” (p. 209). 

The authors then go on to discuss dimensional physics.  It seems that a three spatial-dimensional universe is required.  “A surprisingly diverse array of phenomena hinges on this fact: the inverse square law of gravity, the stability of atoms, and wave equations, among others” (p. 209).  The conjecture of “dimensionally challenged universes” creates other problems: they would be hostile to life as we know it and they would make the acquisition of observable information next to impossible.  The same can be said for altering time: “It seems reasonable to conjecture that altering the number of time dimensions (assuming this is even possible) would also enormously complicate cause-and-effect relationships and consequently make prediction much more difficult if not impossible.  Indeed, the only safe prediction in such a place might be that accurate preductions weren’t possible” (p. 210). 

In the area of discoverability, the authors indicate the following several features of our universe as over against other conjectured universes.  I have always said that simplicity and that which is profound are related and so we see that it is the case in physics.  “The inverse-square laws of gravity and electric fields helped lead to the early discoveries of the universal Law of Gravitation and Maxwell’s Equations” (p. 210).  When we follow the historical trail of observation and mathematics we discover that our universe is intricate, yes; but it is an intricacy based upon simple units.  “The trek from Kepler to Newton to Einstein was facilitated, then, not only by the particular characteristics of our local environment but also by the mathematical simplicity of gravity” (p. 210).  Davies writes:

It is often said that nature is a unity, that the world is an interconnected whole.  In one sense this is true.  But it is also the case that we can frame a very detailed understanding of individual parts of the whole without needing to know everything.  Indeed, science would not be possible at all if we couldn’t proceed in bite-sized stages (p. 211). 

The authors also note the fact of long-term stability within the laws of physics that are at once beneficial for the propagation of life and discovery.  We can, by inference, look at a small representative sample of something and extrapolate larger realities of our universe.  Persistent consistency allows us to do that. 

The properties of the most fundamental units of complexity we know of, quarks, must remain constant in order for them to form larger units, protons and neutrons, which then go into building even larger units, atoms, and so on, all the way to stars, planets, and in some sense, people.  The lower levels of complexity provide the structure and carry the information of life.  There is still a great deal of mystery about how the various levels relate, but clearly, at each level, structures must remain stable over vast stretches of space and time (p. 211). 

With respect to the complexity of life, the authors remind us that there is a delicate balance between simplicity and complexity.  The universe does, in fact, contain nested layers of complexity (e.g., DNA); however, this would be impossible in either a totally chaotic universe or one of utter simplicity composed of hydrogen atoms or quarks.  “Moreover, surprisingly, our universe allows such higher-order complexity alongside quantum indeterminacy and nonlinear interactions (such as chaotic dynamics), which tend to destabilize ordered complexity” (p. 211). 

Of course, although nature’s laws are generally stable, simple, and linear – while allowing the complexity necessary for life – they do take more complicated forms. But they usually do so only in those regions of the universe far removed from our everyday experiences: general relativistic effects in high-gravity environments, the strong nuclear force inside the atomic nucleus, quantum mechanical interactions among electrons in atoms (p. 212). 

Even these regions guide us to relative simplicity: e.g., the Schrödinger Equation.  “Eugene Wigner famously spoke of the “unreasonable effectiveness of mathematics in natural science” – unreasonable only if one assumes, we might add, that the universe is not underwritten by reason” (p. 212). 

There is also the observable phenomenon of hierarchical clustering.  The authors make the claim that the universe’s delicate balance determines the manner of matter distribution.  There seems to be a pivot point between such things as uniformity and diversity, homogeneity and “clumpiness.”  The conclusion is that if matter did not clump in wads between the size of planets and galactic clusters there could be no stars.  If matter did not clump, then observable radiation would not get very far before being deflected into oblivion.  There would be so much space junk that we would get bombed to death and we would be unable to see where it was coming from.  We would have difficulty measuring anything if we lived inside a nebula.  Our vision would be, well, nebulized.  Clumping helped Kepler in noting the motions of the planets, in turn, helping Brahe when more precise observations could be made (p. 214). 

With respect to studying the forces of physics this has been most helpful: 

. . . it’s only because these four forces – gravity, electromagnetism, the weak force, and the strong nuclear force – have widely varying strengths and scales of effect that we can disentangle the effects of each and, hence, study one force at a time.  For instance, at the range of scales from planetary masses to galaxies, the only significant force is gravity, whereas at the level of atomic structure, the only significant force is electromagnetism (p. 214). 

The authors conclude this section with the quotation from Zee: “we can learn about Nature in increments.  We can understand the atom without understanding the atomic nucleus. . . .  Physical reality does not have to be understood all at once” (quoted p. 214).  In fact, this leads us to what the authors refer to next as hierarchical simplicity.  That is, that at each level of discovery there are simple laws with their various mathematical formulae that guide the advance of physical science. 

Consider the transition from . . . gravity . . . to . . . General Relativity.  These two laws inhabit radically different conceptual and mathematical frameworks: one describes forces between particles; the other, curved-space time. And yet we can translate each theory into the other.  Such translation, however, obliterates the simplicity of the theories (p. 214). 

The authors conclude the chapter with some statements on our place in the cosmos.  This is not as much a discussion of space and time as it is a discussion in conclusion of clumpiness.  “. . . we’re the tiny clumps that we’re most concerned about” (p. 215).  After noting the usual “reproachful sermons” about how tiny and insignificant we are compared with the size of the observable universe, the authors make a rather disarming statement:

Actually, over the extreme range of size scales from quarks to the observable universe, the range from humans to Earth is smack in the middle on a logarithmic scale.  But more important, our middling size actually maximizes the total range of structures we can observe, both large and small.  We’re really a very nice fit in the cosmos (p. 215). 

The authors then provide us with a couple of thought experiments to help us sort out how privileged we are to be able to observe our universe.  But before I get to those, let me say that there are a couple of small things in the book that make it well worth the price: The chart on page 216 is one and the revision of the badly obsolete Drake Equation is another (pp. 337-42).  I will discuss the Drake Equation later; but for now, let us look at Figure 10.4.  At the bottom of the chart coming in at a whopping 10^-20 meters are Quarks.  At the top of the scale is the diameter of the observable universe (seemingly always subject to amendment) at 10²⁶ meters [?].  The geometric mean is 10³ and humans and the earth fall neatly on either side of that geometric mean at 10⁰ and 10⁷ respectively (p. 216).  Cool!  In the middle, we don’t collapse under our own weight as would the aliens in the trailer of Men in Black II. 

But in the middle, we are also in the best position to observe the universe.  If we were the size of an ant, we wouldn’t have the visual capacity to clearly resolve a full moon.  Obviously, as any adventure at a picnic will prove, ants are not visually (pheromonically?) challenged in sunlight at high-noon.  Ants can resolve one degree; humans can resolve about one minute of arc.  Because of our size, we can grind a 12 inch mirror in our shops (or get a second job and buy one from Meade or Orion), and set up a backyard scope that will easily resolve to one second of arc and gaze at celestial objects far invisible to the naked eye.  Small doesn’t help with particle theory either.  Colliders are huge and take up the real estate equivalent to a small dictatorial republic.  Ants would have difficulty building them or generating the energy to run them – despite the fact that insects are said to constitute 40% of the biomass on the planet! 

Bigger may not always be better or even bigger for that matter . . . but that’s philosophy of leadership not science.  We are told that larger animals are not as dexterous as we are.  And if they get too big, they really need and aqueous environment to help support some of their weight.  The beaching of whales and collateral events like un-beaching and/or expiration of the smelly-kind should be evidence to that effect. 

Following Denton, the authors indicate that the control of fire, useful for everything from fireworks to Bunsen burners and forges is most facilitated by beings of about our size.  Of course, during forest and range fire season it would be really useful to have a “Paul Bunion sized boot” to stomp out Smokey Bear’s fires; but the point remains: control of fire is the provenance of mankind.  This was a necessary step toward higher technology as was, contrary to that which is politically correct, the combustion of fossil fuels (p. 217).  I will give the authors the final word:

Theoretical physics and cosmology were surely unrelated to humanity’s needs for survival for most of our history.  Our ancestors got along quite well without Bell’s theorem of quantum mechanics, Big Bang cosmology, and the theory of stellar nucleosynthesis.  Nevertheless, in many ways we seem to be curiously overprepared, enough so that when the opportunities availed themselves, we could discover the laws of the universe, even in their most distant and obscure manifestations.  This curiosity fits hand in glove with the other surprising fact that we’ve spent a good bit of ink and paper developing.  We’ve moved from the details of Earth’s geophysics and atmosphere, to the beginning of cosmic time and the forces and constants that apply throughout the universe. Over and over we’ve seen a pattern: the rare conditions required for habitability also provide excellent overall conditions for discovering the universe around us.  At some point, this pattern should lead us to not only re-evaluate certain entrenched assumptions about the universe but even to reconsider our very purpose on this tiny speck orbiting a seemingly inconsequential star between the spiral arms of one ordinary galaxy among billions (p. 218). 

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