For hundreds of years, geographers, physicists, chemists, and geologists labored in disparate fields to understand Earth, its origins, and how it functions as a planet. A new book connects these researchers, from the Ancient Greeks up until the beginning of the Deep Carbon Observatory, to tell the complex and interconnected story of the evolution of deep carbon science.
From Crust to Core – a History of Deep Carbon Science, by astronomer and science historian Simon Mitton (University of Cambridge, UK), recounts the stories of 140 scientists whose work has informed our understanding of the deep carbon cycle. Now in press with Cambridge University Press, the publication will be available in mid-2020.
“At the beginning of the project, I knew I would face a great challenge because the expression ‘deep carbon science’ didn’t exist until the foundation of the DCO,” said Mitton. Additionally, since the topic is so interdisciplinary, Mitton knew that his research would need to cross multiple fields. “I sensed that I would be able to make a significant and completely new contribution to the literature.”
The Alfred P. Sloan Foundation’s science advisor for DCO, Jesse Ausubel (Rockefeller University, USA), initially recruited Mitton for the project in 2015. At the time Mitton hadn’t heard of the DCO, but said that “being a former astronomer, the very name intrigued me.” Mitton attended the October 2015 DCO Synthesis Planning Workshop at the University of Rhode Island, USA, where he presented his book idea and motto for writing science histories: “Ne scripta, sed gentes,” which translates as “People, not papers.” Soon after, he received a grant from the Alfred P. Sloan Foundation to support his research and writing and set out to compile a history of this new scientific field.
To research the book, Mitton visited deep carbon researchers, read more than 600 scientific papers, and talked with scientists at conferences, such as the American Geophysical Union and European Geosciences Union annual meetings. He set out to learn the names of overlooked pioneers, debunk popular myths, and hear the stories behind relevant scientists.
Mitton’s history of deep carbon science starts around 200 B.C. with Eratosthenes, a Greek polymath. Eratosthenes developed a perfect method for calculating the radius of Earth by measuring the length of shadows at midday at two spots, a known distance apart. The story continues with William Gilbert, court physician to Queen Elizabeth I, who in 1601 deduced that Earth functions like a giant magnet, due to some unknown characteristic of the interior. Then the story moves to 19th century France, when people observed the fall of carbon-rich meteorites, which clued them into the extraterrestrial origins of Earth’s carbon. Mitton also explores why people thought that Earth began in 4004 B.C.; a myth that originated with a notation in the King James Bible.
Mitton continues to weave together different threads of research from the first half of the 20th century. Scientists realize that Africa and South America are interlocking puzzle pieces, which suggests that continents can move. Marie Tharpe maps the seafloor with its trenches and mid-ocean ridges. And Marie Curie discovers radium and polonium, which could provide enough heat in the subsurface through radioactive decay to create a hot, liquid mantle. In the 1960s, these strands combine as scientists formulate the theory of plate tectonics, one of the great scientific revolutions of the 20th century.
The book also includes a history of research into deep diamonds, which can act as time capsules from Earth’s past and also from its present in the deep mantle. “Writing a history of [diamonds] has been totally fascinating, partly because no one has attempted to do it before,” said Mitton. The history concludes with the recent, rapid advances in deep life research, as scientists detect, identify, and quantify subsurface microbes worldwide.
The new book not only establishes the state of deep carbon research at the turn of the 21st century, but also provides a baseline for assessing the impact of the DCO. “DCO’s “first decade of discovery” has totally transformed deep carbon science. It’s had an absolutely incalculable and monumental impact,” said Mitton. “I’m able to say that as someone who is independent of all the science.”
Looking forward to the next decade, Mitton predicts that deep carbon science will inform and direct astrobiology research on other planets. So far, scientists have found no evidence of life in the solar system, outside of Earth, but there is still the possibility of life underground. He also sees a need for deep carbon scientists to engage with societal problems, specifically climate change. With the discovery by DCO researchers that natural carbon emissions are just one percent of human emissions, Mitton proposes that scientists now can talk on themes of planetary protection with greater confidence and urgency.
Main image, from left to right: Eratosthenes, William Gilbert, Marie Curie, and Marie Tharp. Credit: Wikimedia Commons