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The metre was originally proposed during the late 18th century — the result of a large-scale surveying expedition undertaken by the French astronomers Delambre and Méchain in 1792 at the behest of the French Academy of Sciences. Contrary to other existing ‘standard’ measures of the time, the metre was to be determined ‘of the Earth itself’ — defined to be one ten-millionth of the circumferential distance from the Earth’s pole to its equator. Given the impossibility of taking such a measurement directly (and noting, of course, the absence of helpful space-based observational platforms) a system of ‘triangulation’ was employed to measure the length of a 10 degree segment of the Meridian of France, spanning from Dunkerque in the north to Barcelona on the Spanish coast. This distance was then extrapolated to estimate the full meridional measure, and the metre was defined as one ten-millionth of this overall value.

In order to compute the length of the meridian arc, Delambre and Méchain employed a system based on surveying — measuring the angles associated with a ‘triangulation’ of numerous geospatial ‘points’ that straddled the meridian. These measurements typically involved observing the angular displacement between various natural and constructed landmarks enroute: mountain peaks, church steeples, etc. The two geodesists' expedition was fraught with numerous difficulties throughout its course — indicative of the tumultuous political tensions [and the extraordinary challenges associated with such scientific undertakings] at the time.

No — despite its many enrapturing elements, the original expedition of Delambre and Méchain serves only as a loose model for étalon, which instead aims to engage with the physicality embodied by the metre and the journey that defined it. Unpacking the conceptual premise that we measure only by measuring against, étalon aims to vest knowledge of the scale and character of our planet in the bodies of each participant through the act of walking — a slow and introspective contemplation of distance travelled and time marked.

Nonetheless, I do intend étalon as an homage to the classical construction of the metre, and as such, I have attempted to develop a system that replicates the spirit of the original survey, if not its specific methodology. Throughout étalon, I too will set out to measure the length and angular displacement associated with arcs inscribed on the Earth’s surface, and through the staging of daily observations, will collect data that enables an estimation of the Earth’s radius and its circumference. Consistent with the original metric definitions, I will in turn generate a new ‘metre’ length — defined as one ten-millionth of the distance spanning from the pole to the equator [as per my estimates].

This process will involve daily measurements conducted between two observers. At the commencement of each experiment, the pair will pace out an arbitrary distance, measure their latitude and longitude coordinates, and, finally, the length that separates each from the other. If a metre is thought of as the distance between two points, thus is the mode of this experiment revealed.

Measuring by a constellation of fake stars

But is the Earth really a sphere?

While Delambre and Méchain conducted their measurements ‘the hard way’ — computing latitudes and longitudes via detailed astronomical observations — we will exploit modern technology for all it’s worth! Throughout étalon, we will employ GPS technology to measure our angular positions, and a laser rangefinder to estimate distance. Rather than attempting to obtain a single, highly accurate estimate (a’la Delambre and Méchain) we will measure regularly — obsessively surveying the landscape cleaved by the meridian to build a statistical model of the Earth’s characteristics. The final values reported for étalon will be average measures — representing the cumulative contributions of all participants.

This data will be made available throughout the course of the project, via regular updates to our provisional Earth radius and ‘metre’ estimates.

No, not exactly, but it is pretty close. The characteristics of the Earth have nowadays been very accurately surveyed using dedicated satellite systems, and is generally modelled as a slightly ‘flattened ellipsoid'. The departure of the Earth from a perfect sphere is not fantastically significant though: the Earth’s radius varies between 6,384 km and 6,353 km at its maximum and minimum extents.

It is also worth discussing the ‘nature’ of the science to be completed for étalon in this context — étalon is not intended as a detailed scientific survey of the Earth, but is rather a performative art project that incorporates some aspects of science in its realisation. While we will, of course, endeavour to measure the Earth as faithfully as possible, the focus here is on the experience of doing so, rather than the accuracy of the result.