Measure of the Earth

by Drew Martin
For a human-made object there is a person or team of people who conceived, designed, and created it. And then there is the audience...possibly a consumer, or maybe simply an observer. Part of the fascination of the viewer is understanding how this object came to be. What materials comprise it? What was the process? How long did it take? How much did it cost? What is its purpose?

If this object is small enough, and we are permitted to get near it and touch it, we can walk around it, and maybe even roll it around in our hands. If it is large, such as a building, we can also walk around it but might need to properly view it from a hilltop at a great distance or another edifice, and perhaps we can enter it and ascend to its top floor.  But it still does not take that long to understand its dimensions and place in its surroundings.

Imagine this object is a spaceship and you are placed inside it. You would not have any clue about its shape or size unless you left the location where you first found yourself and walked around it, and maybe even did a spacewalk so you could get a good look at it, the same way you would walk around a sculpture in a gallery, plaza, or garden, to take it in from every angle. 

Think about your favorite sculpture. Now think about having never seen it before, and being place somewhere on its surface, but you are the size of a flea. How would you understand its shape, size and placement? If its size is far more massive than you, how would you ever accurately get to know its dimensions and mass?

Replace the human-made object with something from nature and the questions change in terms of how it came to be, but understanding its form is still a matter of observation that requires our mobility and senses. Scale up a rock, to a continent and the challenge is the same. You need more time and input to understand its shape and size. Scale it up to a planet and you will find a level of mystery and misunderstanding that will evoke creation myths and ideas that challenge reality. 

For thousands of years of human civilization, our planet Earth was an unknown object that, at best, was depicted in crude maps. It has only been about half a century that we were able to photograph it from its orbit. And even when scientists from the past agreed it was round, they had no real understanding of its precise size. And once they concluded it was a globe of certain dimensions, there were still two theories by the 17th Century that questioned its true shape.

The first approach, supported by René Descartes in France, was that Earth was egg shaped, narrower at the equator and elongated at the poles. This was countered by Sir Isaac Newton in England, that our planet bulged at the equator and was flatter at the poles. Descartes, the more philosophical of the two, approached the issue with a mixture of science and wild thinking. Newton, more scientifically diligent, had reached his answer through mathematical deduction.  

This debate had far-reaching political and national interests. It is no wonder France and England locked horns on the issue - both were big colonial powers with invested pride in their greatest minds and nations' scientific achievements. The truth was that Newton's reasoning was more modern and scientific but for a French scientist to embrace it, would be unpatriotic bordering on treason. So the two nations literally stuck to their guns. 

The reason why this mattered at all, considering that most people do not pay much mind to such topics, actually reached far beyond the scientific community and was indeed extremely practical. Colonial powers relied heavily on maritime accuracy to get from their country to their colonies and back. Many (stolen) riches and lives were at stake and depended on making transatlantic voyages in wind-powered, wooden boats. A perfect sphere, on which degrees of longitude and latitude were established, would be smooth sailing in terms of destination points. But this global location network was off. And scientists noticed something was different about how a pendulum clock that was calibrated with a certain accuracy in Europe behaved quite differently at the equator. So in order to correct their perceived anomalies, it was crucial to get a precise measurement of how the Earth was truly shaped. To do this required triangulation, the science behind our modern-day GPS navigation. 

Triangulation is a field we take for granted, especially when we considered that more than three hundred years ago there were no satellites or even planes. So triangulation meant creating a super straight baseline for miles along the ground, and using known heights (of mountains and volcanoes) to calculate the curvature of the Earth in order to adjust the degrees of longitude and latitude. Latitude was the most urgent to understand because that is where the precision in destination mattered most in a transatlantic voyage.

I recently finished A Measure of the Earth by Larrie D. Ferreiro, which is a rollercoaster ride of the first international scientific expedition, the Geodesic Mission (sponsored by Spain and France) in the 1700s, to Ecuador (then Peru) to measure a degree of latitude. But this expedition, for the most part, looked anything but scientific. Baseline towers were vandalized by the locals, lines of credit were wasted on extravagant accommodations, some of the scientists became idle with all the delays, or were battered by the field conditions, intoxicated in local affairs, and caught up in brawls and lawsuits, all of which jeopardized their goal. 

Spoiler alert - the scientists finally and pretty accurately get their measurement, which actually supports Newton's prediction. Some went on to continue contributing to the fields of their interests. While some of the lesser important members of the expedition were abandoned with no way to return home.

Despite all the challenges and moments of failure, the eventual success of the mission inspired future international scientific enterprises. "The most famous of these...were the cooperative voyages from 1761 to 1769 to observe the transit of Venus, so as to establish its distance from the sun to allow more precise calculations for planetary astronomy. Scientists from Britain, France, Russia, and Austria coordinated their observations around the world and corresponded with each other about the results, despite the intervening Seven Years War (1756 - 1763) that pitted their nations against each other."

The Geodesic Mission had many other positive results. It led to the concept of a standard system of measurement, which evolved into the metric system. And witnessing the effects of smallpox across South America led to mass inoculations against pandemic and endemic diseases. The mission was also a revelation from an anthropological point of view. South America had been off limits to the rest of the world because Spain, the superpower that dominated it, wanted to keep it in the dark. Reports by the French scientists about the people and customs of the regions to which they traveled painted a better picture of the lifestyles and achievements of people under Spanish rule. 

My favorite story about the expedition is that one of the scientists used the term "equator" so much and spoke of the "people of the equator" that when this region gained independence, it naturally became the name of the country - Ecuador.