To you, an educated person living in 2017, it may seem obvious that the world beneath your feet consists of rock, rock, and more rock, some molten rock, then a bunch of hot iron and nickel down at the core. But long before eighth grade Earth science classes existed to share this worldview, people were trying to envision what our (definitely round) world looks like beneath its skin.
As a fascinating map exhibition shows, there was no shortage of creativity involved.
Beneath Our Feet: Mapping the World Below features a wide array of maps created by cartographers, thinkers, and scientists over the last 400 years, with a focus on the 19th and early 20th centuries. The collection, which is housed at the Norman B. Leventhal Map Center at the Boston Public Library, offers a window into how our view of Earth’s interior has changed with the times—from a spiritual underground to a source of minerals and fuels that ushered in the modern era.
“The 19th century was a time that map makers started to focus on particular singular topics [like geology] and trying to map them,” curator Ron Grim told Earther. “The thing we’re trying to get across to a larger audience is the variety of maps being produced, and how our understanding of the Earth has changed.”
Indeed, as the exhibit shows, it’s changed dramatically. A page from a geologic textbook published in 1830 offers one of the first modern(-ish) depictions of Earth as planet with concentric layers and hot, “combustible” materials in the interior, which helped form the world’s major mountain ranges.
While quaint by modern standards, it was a dramatic step forward, scientifically speaking, from the maps drawn a few centuries prior. Take the map of the Earth below, draw by 17th century Jesuit priest and scholar Athanasius Kircher. Kircher’s depiction of the planet’s interior shows all of the major water bodies connected by a series of underground channels fed by oceanic whirlpools.
“That’s just totally somebody’s imagination,” Grim noted.
By the late 19th century, the US Geological Survey was established and geology was expanding as a profession. Maps of Earth’s subterranean started to look more modern. They also proliferated to serve a variety of purposes, from charting out coal and oil deposits to excavating archaeological ruins.
Grim’s favorite is a rare shaded relief map of Yellowstone National Park, created by USGS mapper John Renshawe in 1914. Unlike typical topographic maps, which rely primarily on contour lines to indicate relief, Renshawe added color to his map in a painter-like fashion to make mountains, lakes, and rivers pop. “His maps are just artistic,” Grim said.
Grim hopes visitors walk away with a better appreciation of how long it took us to develop our modern scientific perspective on Earth’s interior, and how diverse views of the planet beneath our feet were in the past.
“It took the accumulation of a lot of knowledge to get to where we are today,” he said.