We Are Stardust

in The Salon by

We don’t have bodies; we are bodies. — Christopher Hitchens

In a previous article, I gave a brief look at the reality of our unremarkable place in the Universe. I also mentioned the possibility—even the likelihood—that our universe is only one among billions or trillions of universes; and that, if correct, such a picture of a mega-vast cosmos would be an explanation of sorts to the existence in these parts of physical constants and conditions amenable to the emergence of life. We would be living in a rare, Goldilocks realm, because of a statistical fact. Among so many bubbles of energy, it is not odd that at least one would make possible life as we know it.

We do know for sure that there is at least one species of living beings with enough awareness to ask fundamental questions about reality, and with the ability to propose plausible answers which they in turn test by experiments and observations. In short, they are capable of doing what we call science.

Many people express their resistance to the fact that we are merely material, made up of “stuff.” The idea that there’s more to humans, in the form of “souls” or “spirits,” is endemic to the religious among us, who often conceive a realm for the material, this “vale of tears,” and one destined for “souls”—which in turn consists basically of two imaginary places: one for the damned, “hell,” one for the rewarded, “heaven.” Religious dogmas have the pretension of explaining it all, ending up explaining nothing. Since the 17th century, what we now call the Scientific Revolution began to supplant non-explanations and bad explanations with good explanations.

Science, an international and intergenerational enterprise, has figured out that our bodies are made up mostly of four chemical elements: carbon, hydrogen, oxygen and nitrogen (CHON). We are 96 percent CHON, mostly water, a compound of hydrogen and oxygen. As kids already know by the fourth grade or so, each molecule of water is made up of two atoms of hydrogen and one atom of oxygen. The rest of the stuff in us includes elements like sulphur, calcium, potassium, iodine, phosphorus, iron, and so forth. All those raw materials are assembled in complex organic molecules (“organic” as in carbon-based, mostly in what we call proteins), of which the most essential is DNA (deoxyribonucleic acid, carrier of the genetic code).

Where do all those elements come from? Hydrogen, the “H” in CHON, was made in abundance during the first instant of the Universe, the so-called Big Bang. Observations of the oldest stars in the known universe have shown that they are made up exclusively of hydrogen and helium (He, the second element in the Periodic Table, also made mostly during the Big Bang, through the fusion of hydrogen nuclei in a process known as Big Bang nucleosynthesis). Second-generation stars like the sun are still made up mostly of hydrogen and helium, but also contain traces of heavier elements, which were in turn the product of nuclear fusion that took place inside stars (a process known as stellar nucleosynthesis).

Stellar nucleosynthesis is capable of producing elements heavier than hydrogen and helium, up to iron. To produce nuclei heavier than iron, a remarkable event is required, a supernova, because of the enormous amount of energy needed to produce heavier elements through nuclear fusion. A supernova is an exploding star, whose energy output is so huge that for weeks its light is brighter than that of the hundreds of billions of stars present in the same galaxy. Upon their explosions, supernovae scatter atomic material—the elements, up to iron, heavier than H and He—through space, while the heat and energy of the explosion yields elements heavier than iron (including silver, gold, and uranium). All that material often mixes with interstellar clouds of hydrogen and helium, which coalesce due to gravity to form new stars. Our nearest star, the sun, is the product of such a process.

Some of that stuff scattered by those explosions ended up in our bodies, mostly in the form of CON (without the H, which was made much earlier when our universe was just appearing) which, not surprisingly, are the most common of the nuclei heavier than hydrogen and helium present in the Universe. Life is “pragmatic” and made use of the raw materials that were available. As Astrophysicist John Gribbin put it, “it can hardly be a coincidence that carbon, nitrogen, and oxygen are among the more abundant products of nucleosynthesis inside the stars.”

That is the origin of the iron present in our hemoglobin. It came from the stars. There is a basic kinship between stars and humans. We are stardust, as American astronomer Carl Sagan was fond of reminding us. All those atoms present in our bodies are also “energy,” which materialized in line with the relationship between matter and energy, as first proposed by Albert Einstein in 1905, his Annus Mirabilis. The energetic event that produced quarks, electrons, neutrinos and electromagnetic radiation (light, from the more energetic gamma rays to visible light to radio and micro waves) was the Big Bang. The quarks in turn formed protons and neutrons, which ended up assembled in the nuclei of atoms. Given the conditions of energy, temperature and pressure present in those nuclear furnaces we call stars, many of those nuclei fuse with others to yield atoms heavier than hydrogen and helium.

The most important contributor to the theoretical aspect of nucleosynthesis, which has been confirmed by observations, was English Physicist Fred Hoyle. Hoyle’s maverick ways may have cost him a Nobel Prize, but he is regarded as a great scientist who deserved more recognition when he was alive. His contributions to the understanding of Big Bang and stellar nucleosynthesis speak for themselves.

Given all this, I do not mind being made up of “stuff” (“star stuff,” as it turned out). Mythological stories (think, for instance, of the Judeo-Christian, infantile creation myth or the unimpressive “burning bush” at Mount Sinai) pale in comparison with the wonders of the Universe.

Roberto Ariel Fernández is the author of six law journal articles about constitutional issues, including the Puerto Rican colonial history. His 2004 book, 'El constitucionalismo y la encerrona colonial de Puerto Rico,' can be found at the libraries of Princeton and Yale.

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