The Many Wonders of Oxygen
The Bible declares that we are “fearfully and wonderfully made.” Yet, in our busy world, we rarely stop and reflect on the extraordinary events happening inside our bodies that allow us to even contemplate the beauty and complexity of the environment we find ourselves in.
As you sit and read these words for example, your lungs extract 250ml of pure oxygen from the air every minute to power the myriad metabolic activities within your 37 trillion body cells. 500 million breaths take us from one end of life to the other. And yet, according to the distinguished physician, biochemist, and Senior Fellow with the Discovery Institute, Dr Michael Denton, our oxygen-rich world provides powerful and compelling evidence of nature’s prior fitness for air breathing creatures such as you and me.
Many of the following details were taken from Denton’s newest book The Miracle of Man: The Fine Tuning of Nature for Human Existence, Discovery Institute Press, 2022. Here is a video trailer of the book:
No Accident
Oxygen is derived from the cores of highly evolved stars that have ceased to fuse hydrogen nuclei in their searing hot cores. Denton explains that the level of oxygen in Earth’s atmosphere – 21 percent – is highly fine-tuned to allow both efficient respiration and combustion – the chemical reaction that allows humans to extract energy from burning fuels, which kickstarted our technical civilization. If the oxygen level were to fall much below 16 percent, human cognitive faculties would be severely compromised, migraines would come far too frequently, and even moderate physical activity would prove exhausting. What’s more, plant-based fuels would not stay alight. Below 12 percent, no combustion at all would be possible.
With anything higher than 24 percent, however, forest fires would ravage vast swathes of the continental earth. In addition, elevated oxygen concentrations would generate much higher levels of what’s called reactive oxygen species (such as hydrogen peroxide) inside our cells, which would degrade biomolecules at dangerous rates. Furthermore, Denton also points out the extraordinary fire retarding properties of nitrogen, that all but inert gas which makes up 78 percent of the earth’s atmosphere, keeping oxygen’s vicious reactivity in check, allowing fires to burn, but not uncontrollably so.
Intriguingly, the connection between life and fire is also a theme running though the biblical narrative. In Exodus 3, the Angel of the Lord appears to Moses in the wilderness as a burning bush that did not consume the wood, and in the Book of Hebrews, we learn that “our God is a consuming fire.” The spiritual imaginary linking the “living God” with the properties of fire is especially poignant given how much we now know about this gas of life.
More Miracles
Denton calls our attention to yet more life-affirming properties of oxygen. Consider, for example, the solubility of oxygen in water. If oxygen were just a little more soluble in water, the oceans would draw down too much of it from the atmosphere, stymying the progress of air-breathing land animals. If it were only slightly less soluble in water, the marine environment upon which human civilization depends, would collapse.
Here again, the level of oxygen in the atmosphere, with its just-right solubility, allows for life to flourish on our planet. But if oxygen is not sufficiently soluble in water, how can enough of it reach the innermost recesses of the human body? It turns out that some unique properties of transition metals – iron in particular – are found at the heart of the myriad hemoglobin molecules packed inside our red blood cells. The chemical properties of iron make it possible to bind oxygen molecules just strongly enough to carry it to all cells of the human body, but weakly enough to have it released into the tissues of our bodies.
In the upper atmosphere, ultraviolet light from the Sun breaks up oxygen molecules (O2) into single atoms. Then, an oxygen molecule can combine with an oxygen atom to create a gaseous substance called ozone (O3). Too much ozone is toxic to life, but the small amount created in the earth’s stratosphere helps protect life on land from the most damaging effects of ultraviolet light. Thus, in a splendid symmetry, we see the molecule of life also acting to protect life.
Leaving the Stone Age
Denton also calls to our attention the amazing anatomy and dexterity of the human form, particularly in relation to our suitability for initiating and controlling fire. Believe it or not, the dimensions of the human body are ideal for creating and maintaining fires. If we were the size, say, of an ant, we could never get close enough to even a small fire without being cooked. But if we were twice as big, our mobility would be severely curtailed, making us more likely to stumble, like some fumbling Prometheus, and fall into the fire than anything else.
The unique properties of oxygen allowed our ancestors to tame a flame, but not just to keep warm and cook food, but also to use its unique properties to reduce metal ores of copper and tin using charcoal. Materials such as these launched the human technological revolution, with the creation of brand-new materials like bronze. Later, when humans learned how to create even hotter furnaces, the extraction of iron from its ore became possible, and just think how that metal has transformed the human world. Indeed, in a very real sense, we still live in the iron age. Similarly, the combustive properties of oxygen allowed humanity to roast limestone into lime, a key ingredient of concrete, as well as to exploit vast reserves of fossil fuels which launched the industrial revolution.
Small Mercies
The secular Zeitgeist prevailing today cannot bring itself to publicly acknowledging the extraordinary examples of nature’s prior fitness for carbon-based life in general, and human life in particular. There are no cogent theories as to why, for example, the earth’s atmosphere has the just right levels of oxygen to enable human flourishing to the degree that we now understand and enjoy.
Here’s an arresting thought; The Bible tells us that all the amazing chemical and physical properties of oxygen were foreordained, back before galaxies and stars and planets, and…. life and Darwin. They were all set in place before humankind appeared. Coincidence? Serendipity? The best the unbelievers can say is that nature ‘knew we were coming.”
But we can know better than that. The prophet Jeremiah, writing in the book of Lamentations, expressed these miracles far more eloquently than any scientific theory can:
Because of the Lord’s great love we are not consumed,
for his compassions never fail.
They are new every morning;
great is your faithfulness.
is that author of eight books on amateur and professional astronomy. His latest book is Choosing & Using Binoculars, a Guide for Stargazers, Birders and Outdoor Enthusiasts (Springer Publishing, 2023).
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