A story about the origins of life in the cosmos starts at Earth’s equator, where Dian Fiantis, a professor of soil science at Andalas University in Indonesia, investigated how seemingly dead environments come back to life. In 2018, she traveled to Mt. Anak Krakatoa (which emerged after the famous Krakatoa’s eruption) to collect the volcanic ash it ejected two months before. In her lab, she found out that volcanic glass (SiO2), the dominant chemical found in the ash, has extremely tiny holes that could store water. “A good place for cyanobacteria to grow,” said Fiantis. The microbe, which scientists called “nature’s little alchemist,” engineered the surrounding environment so that complex living systems like lichens and vascular plants could grow.

Fiantis’ research shows us what happens “before life” in modern circumstances. It might not tell us how life began on the early Earth, but this is the closest contemporary example of the blurry line between life and non-life. Just like a meteor impact or active hydrothermal vents, a volcanic eruption could represent the hellish conditions where nature may “mix things up and select for chemical configurations and try new things [that lead to life],” said Robert Hazen, a mineralogist at the Carnegie Institute of Sciences. 

Chemical (r)evolution

Hazen is one of many scientists who are now proponents of “evolution before life,” an idea referring to a universal chemical evolution that spans billions of years and comprises all possible space in the universe. This hypothesis argues that life emerged gradually as molecules evolved from simplicity to complexity, undergoing selections until reaching biological functions. 

Science can’t create life from scratch yet, and no one has convincingly explained how life emerged on Earth in the first place. But the theory of chemical evolution, which stands on hundreds of scientific papers since the 1990s, is hot on the trail of science’s greatest enigma. It is not an “Earth-bound” theory, and it is now testable with AI technology.

says Joshua Goldford, a computational biologist at California Institute of Technology. 

Do minerals evolve?

One day in May 2024, grayish clouds were covering the sky of Providence, Rhode Island. On the ground, ten minutes away from the city’s train station, hundreds of scientists gathered for Astrobiology Conference (AbSciCon) 2024, organized by the American Geological Union (AGU). On the first floor, the exhibition hall was full of posters explaining the possibility of life beyond Earth, but people were flocking upstairs for afternoon parallel sessions. One of these, a session called “Evolution Before Life,” attracted a standing-room-only crowd.

Hazen opened the session with a talk on mineral evolution. He says that, from the earth’s formation 4.6 billion years ago, there is a pattern of increasing complexity in mineral history, resulting in more than 6000 complex minerals we know today. He thinks the existing laws of nature are not enough to explain such a pattern in the universe. There must be an additional law that governs how atoms and molecules come together to create more and more complex entities across time, he says. 

For years, Hazen worked with a team of scientists and philosophers to develop “the law of evolving systems,” a process of chemical evolution based on the selection of “functions.” The term “function,” says Hazen, is contextual depending on our own inquiry. He mentioned that within a vast amount of possible protein configurations, nature could select different functions such as nitrogen fixation, a spider web, or stomach enzyme.  Each has its own history of selection. In mineral evolution, the selected function is its stability. The more stable the mineral, the more likely it survives. 

This process of selection applies to all matter that composes living and nonliving things in the universe, including the continuous process which connects the two worlds, or what is popularly known as “the origins of life.” Minerals did not evolve solely within their own kingdom, they crossed paths with other chemical reactions, selecting molecules suitable for life, says Hazen.

But biologists have doubts about the use of the term “evolution” by chemists and mineralogists. In the Q&A session, some biologists highlighted how they think of evolution differently. One argued that linear progress from simplicity to complexity is not the heart of biological evolution. Each microbial world, for example, is unique and it doesn’t make them more “advanced” than the other group. Instead of a “ladder,” the scientist suggested, biological evolution is a tree with messy branches.  

Greg Fournier, a geobiologist from Massachusetts Institute of Technology (MIT), says that both chemical and biological evolution “can include selection and generated diversity,” but he says only biological evolution has a concrete form of heritable information in the process—a concept that chemists are still grappling with.

Universal evolution

Hazen, who has published more than 25 books on mineralogy and origins of life science, contends that evolution is not exclusive to the living world. The process of selection, as a driver for increasing complexity, applies to many other worlds such as music, languages, as well as chemistry.

The idea of “evolution before life” is not new, says Hazen. In the 1990s, in his book At Home in the Universe, Stuart Kauffman proposed an idea of how self-organization of matters could lead to “spontaneous order.” (In fact, Kauffman helped review Hazen’s recent paper on mineral evolution). Hazen has also worked with Jack Sozstack, a veteran prebiotic chemist at the University of Chicago, to build the concept of “functional information.” Together they developed a formula that describes how molecular complexity relates to its function. Hundreds of research papers have also developed the terms “emergence” and “chemical evolution.” The theoretical foundation for chemical evolution is quite robust, says Hazen.

Hazen wonders if the hesitation surrounding the idea, especially his law of evolving systems, is more about its philosophical implications. Imagine a white paper cup in our hand. Hazen says that physical laws could describe its materials, shape, mass, and other quantitative measures but it never explains function. It could be a place for coffee, tea, pencils. Function is contextual. “And when you’re saying ‘function,’ you’re saying ‘purpose,’” he said. This is where many scientists grow uncomfortable. 

Scientists might believe that nature exhibits no purpose. But “that’s not the way we experience the universe,” says Hazen. He argues there are two arrows of time. The first arrow follows the second law of thermodynamics where things are heading to destruction and disorder. We see red maple leaves falling in fall, white hairs appearing on our heads, and loved ones dying. But, says Hazen, we also see children being born, flower buds popping out from dried branches, or lush rainforests growing out of volcanic ash. This is the second arrow of time: an arrow of increasing order in the universe. “For me, science should explain this phenomenon.”

Life beyond Earth?

Hazen is not the only one who thinks that evolution happened before life. Lee Cronin, a chemist at the University of Glasgow, developed Assembly Theory, a conceptual construct that reflects a similar idea of how life evolved through the process of chemical selections. For this theory to be validated, Cronin thinks it needs not only experimental support but “it must be able to predict something new.” 

Seeing the question of the origins of life through the lens of chemical evolution would enable us to look for life elsewhere, they say. Assisted by machine learning, scientists at Hazen and Cronin’s labs have developed methodologies to detect biosignatures in the moons of our solar system. In Jupiter’s moon Europa, where volcanoes might smolder under its icy surface, life could possibly exist. This October, NASA’s Europa Clipper will shoot toward the moon to collect gasses and molecules in its atmosphere, aiming to assess its habitability. It is not clear whether chemical evolution-based biosignature detectors will be used, but scientists say the results might reveal chemicals that were also present in the prebiotic earth. No one will know until the spacecraft flies by Europa in 2030.

Life finds a way

Six years after Fiantis collected her volcanic ash, life is thriving in the Krakatoa volcanic complex. Nature’s “little alchemist” had enchanted the hellish environment into a tropical paradise through chemical spells. Fiantis found the soils had higher concentrations of certain metals like calcium, magnesium, and phosphorus. All play crucial roles in plant metabolism, acting as an important activator of many biochemical reactions. 

Under this spell, green lichens blanketed Anak Krakatoa, 40 species of orchids, six species of mammals, 47 species of birds, 19 species of bats, and 17 species of reptiles roam its surrounding islands, creating a scene of life as we know it today and hinting at a chemical evolution that first animated the island.