AT CHRISTMAS, I was out on the prairie again. Third time in a year. It seems like I can’t stay away. This time, I came up out of Council Grove, Kansas, at seven A.M., just around sunrise. For about a minute and a half. I saw the sun and the full moon balanced evenly at the opposite ends of the sky. And here was I, riding along the bald and slightly arched surface of the earth, halfway between the two.
What are we doing on this planet, and how did we get here? It took only a glance to tell that there would not be anything like us found on the yellow sun or the fast-paling moon. The Earth has one thing that neither sun nor moon has ever had.
And that one thing is clay.
I stopped by the Spring Hill Ranch, where there’s a break in the fence. I like to walk the erosion gullies on the virgin prairie. There are fossils in the lower strata, as thick as nuts in an almond bar. But that morning, I found clay. I dug it out with a stone and formed it into small flutes and bowls. It was almost greasy to the touch, it had a sheen about it, and you could shape it into anything.
What if clay is alive? Biologist Hayman Hartman thinks it is. If he is right, then perhaps our ultimate ancestor really was adam, the Hebrew word for “red clay.”
“Our difficulty,” says Hartman, “is that we think of organic molecules as somehow being the necessary and sufficient condition for life.” But what if life were a more pervasive phenomenon than that? What if life were already implied in the magnificent, supple matrices of the clays?
The word “organic” comes from the Greek organon, meaning “tool” or “instrument,” the latter itself derived from words that mean “to do work” or “to perform a sacrifice.” By these definitions, clay is at least as lively as the so-called organic chemicals. It may quite literally have been the matrix (the old word for “womb") that spawned all the creatures now inhabiting the earth.
In 1953, chemist Stanley L. Miller shot a tankful of inorganic chemicals, designed to simulate the ocean, full of simulated lightning bolts. He succeeded in synthesizing simple organic compounds, thus giving rise to the “organic soup” theory. The idea is that life on Earth began when inorganic chemicals were bombarded with electromagnetic radiation. Presto! Life ensues.
Cosmically speaking, however, it is all too easy to make organic compounds. Hydrogen, carbon, nitrogen, and oxygen—the chief components of organic compounds—are the commonest elements in the universe. Microwave investigations of the deepest galactic clouds reveal the presence of the ingredients of organic chemistry. Compared to them, the Earth is poor in these crucial compounds. So why should it be that the Earth, alone of all the bodies with which we are acquainted, should harbor what we call organic life?
The mother function is apparently far more active than Miller (and many of our parents) expected. Indeed, it is the crucial factor in the equation. To “spill your seed on the ground” is to spend your energy where it receives no answer. The flaw in Miller’s experiment was to think that the ocean was anything like a retort. Even had small organics been created in it, they would almost certainly have been churned to pieces before longer and more lifelike chains could build. There was not enough motherly repose in the open sea, nothing to enfold, contain, and order.
This is exactly the function of a clay. Formed by water, it is the seat of a wild, capacious order. When the physicist Erwin Schrodinger speculated on the fundamental building blocks of life, he concluded that the basic component would have to be an “aperiodic crystal,” that is, an ordered and repeating structure that nonetheless left room for a whole variety of actualizations. Only such a machine, he reasoned, would be sufficiently supple and dynamic to engage in the constantly shifting behaviors of metabolism, growth, and reproduction. DNA—discovered decades after Schrodinger’s assertion—admirably fulfilled these conditions. But so does clay.
The clays, unlike their parent rocks, have no inaccessible interior, but instead a very large reactive surface. They unlock the potential waiting in raw matter. Clays stack, wrap, pile, and exfoliate, like leaves or sheaves of paper. In fact, experiments have shown that a single gram of a clay powder can have a total surface area larger than a football field. It is as though you set out to write a book and had to decide between writing on a ream of paper or on a raw tree. Which to choose?
But clay is more than an empty book. It is already encoded with a vast array of possible meanings. Each layer of a clay is a matrix of molecules that is well ordered but marked with a succession of dimples, holes, and ragged edges. In other words, each layer is a template with tendencies.
Isaiah, describing how God would cause righteousness and praise to arise, compared the act to a garden, which “causes what is sown in it to spring up.” The ground itself is as active as the seed. The seeds of organic life, attracted to the patterns of a clay matrix, might well have found there the structure that makes all of us possible, and the means to maintain and reproduce it.
Yet do clays actually behave like this? Direct evidence is lacking, since even to measure the order in clay crystals requires a scale of microscopy that is only now beginning to become available. X-ray diffraction technique and the scanning electron microscope, technologies that permitted our first glimpse in the macro world of the clays, are too blunt as tools to assess and compare the levels of patterning in clays. The new atomic-forces microscope shows promise for unraveling the complexity of this micro level of clay order.
Was clay, then, the necessary partner for the birth of the organic realm? Hartman says, “There are only two things in the universe that require liquid water for their existence: organic life and clay,”
The oldest rocks that we can find on earth are a mere 3.8 billion years old, nearly a billion years younger than the earth itself. It is impossible therefore to find a “fossil” record of the earliest clays. But there is a type of meteorite, called a carbonaceous chondrite, whose average age is about 4.5 billion years, comparable to the Earth’s. Certain of these meteorites contain both liquid water and iron-rich clays. The same ones also reveal the presence of amino acids and other complex organic compounds. On the other hand, those that contain no liquid water reveal no clays, and those without clays have no organic compounds. Since each of the meteorites evolved in isolation in deep space, there is evidently a connection between the water, the clays, and the growth of long-chain organic molecules.
In its first billion years, Earth was a rather different place than it is now. Oxygen was rare, and iron was common and very reactive. Nothing grew on the surface of the planet, so the land flowed downhill into the broad shallow shores of the seas. Most clays formed there or near the sea-floor vents, where fresh iron was pumped upward from within the crust.
Still today, in deep-sea trenches largely deprived of oxygen, clay species rich in iron and potassium form and evolve within the pore spaces of seabottom minerals, relatively protected from the surrounding events. These clays closely resemble what clays must have been on the early Earth. And they behave as though they were alive. They go through a process of transforming growth. A young one resembles a little worm, and blooms into a pattern of open curves. Another begins as an isolate thread, and grows into nodules that some scientists have compared to peppercorns but that also have the comb structure of a beehive or a sponge.
It might be argued that these patterns are nothing more than crystal growth. But the real question, as Schrodinger knew, is how life itself is related to crystal growth. Richly patterned clays might have served as templates for biosynthesis, that is, for the beginning of organic life. It is a statement so simple and obvious that it runs the risk of being ignored, just as the obvious case for plate tectonics was ignored for hundreds of years.
Consider the iron-rich mineral called kakoxen. Tubular in form, hexagonal and hollow in cross-section, this remarkable crystal species looks like nothing so much as the rose window of a Gothic cathedral.
Exactly the same impression is given by computer simulations looking down the bore of a DNA molecule. Seeing both of these together, it is easy to believe that the protected interior of such a crystal might have been the site where organic polymers of the sort that would form nucleic and amino acids were born.
Hartman has an idea how the transition from these probiotic clays to organic life might have occurred. In the presence of ultraviolet light, iron can sometimes capture both carbon dioxide and nitrogen from the air, resulting in the production of citric acid, an organic compound. Amino acids can gradually be built out of citric acid. So seaborne clays on the ancient Earth, deriving their energy by feeding on CO2, nitrogen, and light, might produce the building blocks of organic life.
A basic question for Hartman and his colleagues is this: Do (or did) clays reproduce? In other words, does the particular order expressed in one particular clay create further clays with the same order? Second, is this order dynamic? Does it lead to social interactions among clays?
It’s an exciting question, but possibly a blind alley. After all, the mythology of heaven is full of living creatures—the dwarfs, the fairies, the angels—who do not reproduce as we know it. Perhaps, instead, we could see life as a strategy for fulfilling the wishes of a given matter— whether molecular, cellular, or psychological—endowed by the creator with a constellation of possible forces. Whatever the matter may be, life is neither chaos nor prison, but process and freedom.
The crystallographer A. L. Mackay notes that any lifelike system requires “a stream of energy [that] passes through the system and its environment.” Life begins in this interaction, where the energy is bent and diverted into little chaotic vortices, unexpected patterns, dynamic containers of information. A clay crystal, he says, fulfills just these requirements. He compares it to an abacus, well ordered but capable of many meaningful permutations. A certain minimum energy is required to change it from one state to another. It is therefore a code.
The clay code, however, is more complex than either the genetic code or human language. Only now are we beginning to catch glimpses of its order, and one cannot help thinking that pursuing it will be as fruitful and as endless as the cabbalists’ search for that perfect expression of the Hebrew aleph, by which God created the universe.
It is said in Genesis 6 that once upon a time the sons of God came down to earth and begot children on the daughters of men. If we admit that clay is alive, we must say that it is both more ancient, more widespread in the universe, more durable, and more powerful than we are. Yet it is also less supple and less able to make abrupt transformations. Perhaps this Genesis story can symbolize the rise of life as we experience it, from the joining of organic and inorganic realms. Wouldn’t it be strange if, in the history of the living, clay performed the function of angels?