History of Science: Rethinking the Origins of Plate Tectonics

Many historians have thought that U.S. Navy funding of oceanography paved the way for plate tectonic theory. By funding extensive investigations of the deep ocean, Navy support enabled scientists to discover and understand sea-floor magnetic stripes, the association of the deep trenches with deep-focus earthquakes, and other key features.

At a lecture at the Royal Institution on Monday, May 12, 7-8:30pm BST, Rethinking the origins of plate tectonics | Royal Institution, historian of science and geologist Naomi Oreskes presents a different view: the major pieces of plate tectonic theory were in place in the 1930s, and military secrecy in fact prevented the coalescence of plate tectonics, delaying it for three decades.

Decoding Our Planet: The Making of Geophysics

The lecture will follow a day-long workshop on Decoding Our Planet: The Making of Geophysics. The workshop will explore how we come to understand the origin and basic physical processes of our planet. Answering this question requires us to understand the origins of modern geophysics, the science investigating everything from gravity and magnetism to earthquakes, climate change, and plate tectonics. It will bring together leading scholars from history of science, and geophysics, and philosophy of science to explore how modern geophysics took shape in the 19th and 20th century.

The workshop was organised by Katy Duncan, Postdoctoral Freer Fellow at the Royal Institution (Ri), and Miguel Ohnesorge, a philosopher and historian of science, Postdoctoral Fellow of the British Academy, based at the University of Cambridge. It emerged from their aligned interests in geophysics, and their desire to create a network of others who share that interest. The Ri, Katy explains, was central to consolidating geophysics as a discipline in the mid 19th century, making it the perfect home for the workshop.

The history of plate tectonic theory

By the 1930s, scientists had developed an understanding and proposed models of continental drift and sea floor spreading driven by convection currents. This research, however, was interrupted by World War II. Following the war, the U.S. Navy’s interest in detecting submarines led to the discovery of magnetic stripes on the sea floor. Rocks on the sea floor were found to be magnetically striped, aligning with the Earth’s magnetic field at the time of their formation, supporting earlier models of sea floor spreading and indicating periodic reversals of the Earth’s magnetic field.

As seismologists became able to figure out the difference between an earthquake and a nuclear weapons test, the US Navy also pursued research into deep earthquakes, revealing that they occur in specific regions, supporting the idea of subduction zones.

As Naomi will explain, much of this research was suppressed over decades for military reasons, delaying major advances in our understanding of the world we inhabit.

“Why do we have to study a bunch of old ideas that aren’t even true
anyway?”

Naomi Oreskes reflects on why examining the history of science has a real impact:

‘So what do we learn from this story? Why is it important to study the history of science? One of
my students once said “Why do we have to study a bunch of old ideas that aren’t even true
anyway?” Well, the reason is because we learn a lot about scientific knowledge when we study
its history, and one of the things that we’ve learned is that scientific consensus takes time. Plate
tectonics was not developed in a “eureka” moment. It took 40 years to gather enough evidence
to convince scientific community. So time matters, because it takes time to do work. And our
conclusions may change and our views may evolve as we learn more about the natural world.
But if scientists have been working on something for a long time and if they have reached a
consensus and if they do agree, then that’s a pretty good sign that the conclusions are likely to
be robust for some period to come.’

And on why broadening the story to include more voices matters:

‘Now we also often teach history of science as a story of great scientists but great scientists are
not the whole story. In fact, as a historian I would argue that they’re not even the most
important part of the story. So we can respect great scientists like Marie Curie and Charles
Darwin. It’s interesting to learn about them as individuals, to understand their
lives, but it doesn’t actually tell us very much about how and why we believe the things we
believe about the natural world. For that we have to expand our scope and look at the scientific
community as a whole, because building scientific knowledge is a community effort.’

Book to attend

Tickets for Monday’s lecture are available on the Ri website.

This event is held in conjunction with Discover200 – a celebration of the Ri’s 200 year history of its Discourse series, CHRISTMAS LECTURES, and the isolation of Benzene.

Naomi Oreskes is Professor of the History of Science and Affiliated Professor of Earth and Planetary Sciences at Harvard University. She has worked on studies of geophysics, climate change and the history of science. She sits on the board of US based not-for-profit organisations the National Center for Science Education and Climate Science Legal Defense Fund. She is a distinguished speaker and has published 10 books, including Science on a Mission and The Big Myth.