I’ve spent the past year and a half writing a book about the chemical story that organized life on our planet. The book is titled A World From Dust: How the Periodic Table Shaped Life, to be published by Oxford University Press before this year’s end. In the process of writing I’ve gained new appreciation for a chemical that is so common, it’s easy to lose sight of how important it is. In fact, you may not think of it as a “chemical” at all, even as its chemical power holds you together in a state of dynamic flow. (Some bottles at the supermarket read “chemical-free” even as they hold gallons of this chemical.) This chemical’s formula is familiar: H2O—water.
No other molecule is as “living” as water, whatever scale we choose, whether large as a solar system, as small as a protein, or as old as the Earth. Geology, chemistry, and biology show connections between water and life, some obvious, others surprising, all “living” in some way.
Very often we see right through the unique and life-giving gift that is water.
The more I learn about water, the more depth I see in the Bible’s metaphor of “living water.” Jesus described himself with this phrase, while alluding to the running water used to cleanse and purify in verses like Leviticus 15:13. When water flows, it lives, and it transforms. This holds deep meaning both for the soul and the body. After all, these two aspects of our existence overlap and have the same ultimate Creator.
I see chemical evidence of the power of flowing, “living” water today, yesterday, and a billion yesterdays ago. From geology to biology to research into the origin of life itself, the power of water shows the faithfulness and creativity of our Creator.
Let’s start with geology. Water is creative—its flow shapes both your feet and the ground beneath them. Every place on Earth, even the driest desert, has been shaped and washed by the power of water. Twenty years ago when I moved from Florida to Seattle, I moved from one water-shaped place to another.
In Seattle, as you might know, we’re shaped by rainfall. This familiarity with water also runs throughout time. Long ago frozen water carved the landscape of the Pacific Northwest with flowing, “living” glaciers. An advancing ice sheet from Canada traveled southwest and ran into the Olympic mountains around where Vancouver is today. The mountains stood firm, cracking the ice in two. One sheet turned west and joined the Pacific, carving the Strait of Juan de Fuca. The other turned south and scooped out the Puget Sound.
In Florida, the water is different, both in temperament and consistency. Routine 4:00 pm summer thunderstorms suddenly pour down rain that pools in your sandals, then stop just as suddenly as they begin. Water as pounding surf atomized rock and shells to make Florida’s miles of beaches. Water also carved deep aquifers underneath Florida, which become evident as sinkholes.
All this power is wrapped up in a tiny package. Water is the mustard seed of molecules. It is composed of two hydrogens and one oxygen, bonded with electrons, as H2O. Water is small enough that all you need to make a molecular model of it is a five things: two grapes (for the hydrogens), two toothpicks (for the shared electrons), and a plum (for the oxygen).
An individual water molecule may be small, but this makes it more exceptional, because it is small yet liquid. Liquid is a living, intermediate state of matter, between the frozen solid state and the nebulous gas state. It’s also hard to reach. It’s easier for molecules to go to the extreme states than to settle in a middle state.
As a result, liquid is an in-between state, neither too hot nor too cold, close enough to touch and yet energetic enough to slide around, flowing as a liquid, condensing into an ocean. In a word, liquid is living. Life as we know it needs water because it needs to be in this in-between state, its atoms coherent yet always in motion.
If liquids are living, then the universe is mostly dead, because liquids are rare. Looking at the periodic table, only two elements out of more than 100 are liquid at room temperature: mercury and gallium. Likewise, most molecules as small as water are gases. Big, complex molecules are harder to make and are therefore harder to find through the universe. Here on earth, water is the only molecule that combines liquidity with simplicity, and we literally have oceans of it.
Oceans open to the sun are Earth’s defining characteristic in the solar system, a gift to our planet that makes it appear as a “pale blue dot,” perceptibly different from yellow Venus and red Mars. Earth is locally unique because all three phases of water—gas, liquid, and ice—coexist under bright sunlight.
Among the scores of moons farther out in our solar system, we have found liquids on four: Jupiter’s moons Europa and Ganymede and Saturn’s moons Titan and Enceladus. These all have a liquid foundation for life, but there are other drawbacks. All of these oceans are far from the bright sunlight that gives complex life on Earth its energy, and most are buried from their atmospheres under ice. I think that any life on these moons would probably be too simple and small to be seen by human eye. (More details are in Chapter 4 of A World From Dust.)
The open, flowing oceans on Earth caused geological evolution, so that our rocks are different from those of our neighbors Mars and Venus. The geologist Robert Hazen estimates that the action of water on the Earth brought about more than 3,000 new minerals when there were only about 500 before, a multiplication of diversity in the rocks from this one chemical, water.
Jade, sapphire, emerald, all were made when water mixed and reacted with the Earth. Mother lodes of ores are found by following the ancient paths of water to where precious metals were deposited. Panning for gold requires a stream of running, living water.
Look at a drop of water in a microscope and you’ll see another way it is “living” water, this time in the realm of biology. Even the most crystal-clear pond water is home to thousands of undulating, spinning, pulsing amoebae and protozoa, a microscopic menagerie. Remove all of these, looking even closer at the atoms in water, and you would see that water is constantly moving around itself, forming, un-forming, and re-forming bonds, in what Bill Bryson described as a “quadrille.” This movement is unbridled, even joyful.
Liquid water hosts life even in extreme conditions. In the deepest parts of the oceans, ecosystems hidden from the sun cluster around bubbling clefts where hot, energy-laden gases escape from the earth. These vents are rich with crabs, lobsters, octopi. These animals bask in and ultimately feed on the sulfurous energy of the earth itself, mediated by the water. Of the four moons with liquid oceans, this looks most like the warm, ice-covered oceans of Enceladus.
I’m trying not to get my hopes up too far for finding complex life on Enceladus, however, because reading the DNA of these animals shows they did not evolve there. The DNA of complex life at the vents matches the DNA of more familiar surface species. This means that many of the creatures near the vents evolved at the surface, where chemical mixing and sunlight allowed their complexity to develop. Then they descended to the vents, where they were kept alive by the water and the earth’s energy. Eventually they lost the pigments, eyes, and even mouths that they didn’t need.
Life needs water and energy to survive, and it changes its form to survive, morphing in ways unthinkable and amazing. Through liquid water, life was able to fill what had previously been empty, to thrive and to surprise. That sounds like grace to me.
Deep-ocean vents may shed light on another dimension to water’s power. At that extraordinary place, water may have shaped the first living things on this planet, bringing a good creation to life four billion years ago.
The chemical ingredients life needs come together at the deep ocean vents: carbon, sulfur, hydrogen, iron, nickel, and especially energy from within the earth. Long ago, water’s chemical power may have brought these ingredients together to shape the first life forms.
I once avoided these ideas because I felt that a chemical bridge from non-life to life threatened God’s creative sovereignty. But I’ve changed my mind. If God came up with the ideas, then they actually convey God’s creative sovereignty. The more I appreciate the dynamic elegance of water’s chemistry, the more I think that God appreciates dynamic elegance, too. All origin of life experiments have an important role for the chemical power of flowing, liquid water.
For example, some deep-sea vents form rocks with holes that look suspiciously like small cells. These cavities naturally stockpile and separate chemicals, like natural laboratories with billions of water-filled chambers. They are lined with iron and nickel atoms that react with the sulfur and hydrogen streaming out of the earth like Champagne bubbles. One of the central molecules in all metabolism, pyruvate, forms spontaneously in these vents, as well as other related molecules. It’s as if a biochemical network is budding from the underwater rocks.
Maybe the heat was more simmering than boiling, say, the toasty temperature of a hot spring at the earth’s surface. This makes a different kind of natural laboratory, where holes in the rock act as gas condensers, collecting and condensing steam in a purifying cycle. Every organic chemistry lab contains complex glass sculptures built to condense and distill. Some hot springs have rocks that do the same chemistry.
Experiments in a similar environment found conditions where simple 4- or 5-atom molecules naturally rearrange into the complex, three-part nucleosides that make up DNA. Just a few weeks ago, the same group identified more pathways that make the building blocks of proteins and cell membranes from the same simple starting material. As these branching pathways grow in complexity, it looks more and more like we are rewinding and replaying the “tape of life” with genuine success.
Origin of life chemistry as a field is full of successes like these but also has a fair share of failures. Usually in chemistry, reactions work best when simplified and purified, but origin of life chemistry is different. If origin-of-life experiments are brought down to earth (with actual dirt), they can work better.
The deep-sea experiment above can’t make pyruvate without the iron and nickel from rocks. The DNA-making experiment needs everything to be mixed together in one pot so that thousands of reactions are run. The more the experimental conditions mimic the geological complexity of the early earth, the more the resulting chemicals appear complex and life-like.
If we can imagine God giving his power to God’s creation, then origin of life chemistry experiments have no necessary conflict with a strong theology of creation. The first biochemical cycles would have obeyed the rules of chemistry, and we know who made those rules. Even the deepest part of the sea at the far extent of Earth’s history is part of God’s creation and ordered by God’s command.
Water is the medium of life-giving grace, and we can see through it to the one who ordered the atoms with the rules of chemical bonding (and the math that sets those rules). In Greek, such rules would be called the Logos—the wisdom and Word by which worlds were created. As a chemist, I am called to seek out the subset of those rules called chemistry, and to understand that God is at work providing and upholding them.
The world looks different if flowing, living water is seen as a chemical gift with the potential to create life. Water is powerful enough to carve landscapes, form gemstones and ores, and support fantastic microbes. Now to these powers is added the ability to make life by reacting with rocks, and the story of creation becomes that much more amazing.
The length of this story is incomprehensible to my small experience. Earth held an ocean of life-sustaining water on its surface for four billion years, not boiling it into steam like Venus or losing it to a barrage of asteroid impacts, like Mars. The word for that duration of constancy is faithfulness. Through eons, God has cared for us by upholding a universe with constant chemical laws, rules that convey the simple grace of living water.