Universe’s Chemical Enrichment Designed for Life

Before the James Webb Space Telescope (JWST) provided its exquisitely detailed view into deep space (the early cosmos), astronomers were able to establish an understanding of how the periodic table of elements took shape. They were able to use ground-based telescopes in concert with the Hubble Space Telescope to observe a consistent, ongoing scaling relationship between star-formation rates, stars’ mass, and the increasing abundance of elements that match the observed features of the universe for the past 12 billion years.¹

What we know is that the periodic table was sparse, initially. The first stars in the universe were comprised of hydrogen, helium, and a trace amount of lithium. The largest of these stars fused hydrogen and helium into heavier elements and scattered these elements into interstellar space when they reached the supernova phase. A second generation of stars formed from the ashes of the first. The largest of these second-generation stars more efficiently generated heavy elements and, when they went supernova, scattered far more heavy-element-enriched ashes into interstellar space. Third-generation stars, like our Sun, formed from the ashes of second-generation stars.

A Consistent Pattern for Most of History
The enrichment of elements heavier than lithium in stars and in the interstellar and intergalactic medium progresses according to a single scaling relationship, one that accurately predicts what astronomers are able to observe in galaxies. As galaxies age, they do, indeed, grow progressively richer in elements heavier than lithium, in keeping with this scaling relationship.

Astronomers have successfully measured the relative abundance of elements in millions of second and third-generation stars. They’ve also determined to a high degree of precision the quantities of heavy elements blasted into interstellar space by supernova eruptions over the past ten billion years. 

However, astronomers’ observations showed hints that this universal scaling relationship connecting star-formation rate, stellar mass, and the abundance of elements heavier than lithium might not match what occurred during the earliest one or two billion years of cosmic history.² These “hints” motivated astronomers to use the JWST to shed light on the star-formation rate, stellar mass distribution, and abundance of elements heavier than lithium in galaxies that formed during the first billion years of cosmic history.   

The JWST Confirms Astronomers’ Hunch
A team of 13 astronomers led by Kaspar Heintz of the Cosmic Dawn Center and the Niels Bohr Institute in Denmark used the JWST to measure the chemical abundances of galaxies just 470–770 million years after the cosmic origin event, aka the big bang.³ They noted that these galaxies proved significantly poorer in heavy elements than would be expected if the universal scaling relationship for older galaxies (formed 2.0–13.8 billion years after the big bang) applied. Elements heavier than lithium were only one-fourth as abundant as the universal scaling relationship would have yielded had it been operating at the same level during that early era. 

Implications for Advanced Life on Earth
The measurements by Heintz’s team indicate that while a scaling relationship does exist in these very early galaxies, it proceeded at a much lower rate than it did from 2 billion years onward in cosmic history. Heintz and his colleagues concluded that “galaxies at this time [previous to the first 800 million years of cosmic history] are still intimately connected with the intergalactic medium and subject to continuous infall of pristine gas, which effectively dilutes their metal abundances.”⁴ (In astronomical terms, elements heavier than lithium are referred to as “metals.”)

The dilution of heavy elements in galaxies that formed during the universe’s first 800 million years suggests that the Earth’s rich endowment of heavy elements is unexpected, by natural processes alone. Our solar system formed when the universe was only 9.22 billion years old. Multiple factors required exquisite fine-tuning for Earth to become so rapidly endowed with the superabundance of heavy elements—the elements without which Earth’s global high-technology civilization would be impossible.⁵ This discovery points to a supernatural Designer who provisioned planet Earth not only for the existence of billions of people but also for spreading the message of his redeeming love to all the world’s people groups in a brief (by astronomical terms) time.

Endnotes

1. Filippo Mannucci et al., “A Fundamental Relation Between Mass, Star Formation Rate and Metallicity in Local and High-Redshift Galaxies,” Monthly Notices of the Royal Astronomical Society 408, no. 4 (November 2010): 2115–2127, doi:10.1111/j.1365-2966.2010.17291.x; Mirko Curti et al., “The Mass-Metallicity and the Fundamental Metallicity Relation Revisited on a Fully T_e-Based Abundance Scale for Galaxies,” Monthly Notices of the Royal Astronomical Society 491, no. 1 (January 2020): 944–964, doi:10.1093/mnras/stz2910; Ryan L. Sanders et al., “The MOSDEF Survey: The Evolution of the Mass-Metallicity Relation from z = 0 to z ~ 3.3,” Astrophysical Journal 914, no. 1 (June 10, 2021): id. 19, doi:10.3847/1538-4357/abf4c1.
2. P. Troncoso et al., “Metallicity Evolution, Metallicity Gradients, and Gas Fractions at z ~ 3.4,” Astronomy & Astrophysics 563 (March 6, 2014): id. A58, doi:10.1051/0004-6361/201322099; M. Onodera et al., “ISM Excitation and Metallicity of Star-Forming Galaxies at z ~ 3.3 from Near-IR Spectroscopy,” Astrophysical Journal 822, no. 1 (May 1, 2016): id. 42, doi:10.3847/0004-637X/822/1/42.
3. Kasper E. Heintz et al., “Dilution of Chemical Enrichment in Galaxies 600 Myr after the Big Bang,” Nature Astronomy2023 (September 21, 2023), doi:10.1038/s41550-023-02078-7.
4. Heintz et al., “Dilution of Chemical Enrichment,” p. 1.
5. I describe many of these factors in my books Improbable Planet (Grand Rapids, MI: Baker Books, 2016) and Designed to the Core (Covina, CA: RTB Press, 2022).