Time passes, but measures remain – or do they?

We ensure fair and smooth trade using standardized and verified measuring instruments, just as people did thousands of years ago. The development of metrology has been fascinatingly intertwined with societal and technological progress throughout human history. The international Metre Convention signed 150 years ago laid the foundation for scientific and technological advancements that will propel us into the era of quantum technology and digital parallel reality of the future.

Already in high school, I was very interested in history and physics, and I chose physics as my field of study just before the matriculation exams. Now, 40 years later, as an experienced metrologist, I find myself in a field where history is constantly present but continuously evolving, creating the conditions for future industry and society.

The study of history continuously reveals new findings about measurement systems in past civilizations, as the discovery of precious metal coins of astonishingly similar mass in Europe and Mesopotamia during the Bronze Age [1,2]. Nearly 4000-year-old administrative documents from ancient Babylon describe standardized mass measurements used in the trade of precious metals [3]. The use of measurement systems was strictly regulated to ensure desired outcomes in trade. For example, in ancient Egypt, deviations from the standard size of pyramid stones could result in the death penalty [4], and in ancient Greece, deviations from official weights resulted in a fine worth 1000 daily earnings [5]. When Charlemagne united the peoples of Europe into his empire in the 9th century, one important project was to standardize the measures used in trade across the empire [6].

While studying applied physics at the University of Helsinki, I became fascinated by how physics could be used to analyse very mundane measurement events, such as weighing in a store or pharmacy, measuring timber in a lumberyard, or measuring outdoor temperature. What is particularly motivating is that through analysis, measurements can be made more accurate and suitable for various purposes.

Many scientists likely made similar realizations long before me. The development of science and geopolitical turmoil in the 18th and 19th centuries, along with industrialization and rapidly growing international trade, led to the creation of a global measurement system through the metric convention signed by seventeen states in 1875. Since then, the number of members has grown to 101, including 37 associate members [7].

Throughout its 150-year existence, the SI system established by the Metre Convention has continuously developed and expanded to meet the needs of evolving industry and society. Initially, it included only units of mass and length and their physical reference standards located in Paris as well as their national copies. Today, the system supporting both physical and chemical measurements, includes seven base units and a large number of derived units, with reference systems maintained primarily by national metrology institutes worldwide. This enables sufficiently reliable and efficient quality assurance of measurements in all industrial and commercial sectors.

The development of the SI system is also essential for utilising future technologies such as quantum technology, atomic-level manufacturing techniques, and future positioning systems. With the 2019 redefinition, the SI is constructed around seven defining constants, allowing all units to be constructed directly from these constants. This makes it possible to realise the units more accurately in different parts of the world, although the magnitude of the units of measurement remains unchanged.

The metaverse will bring together digital virtual reality and the physical reality we experience. The measures and units we use in the virtual world must also be standardized and correspond to their counterparts in the physical world. Digital SI standardization is used to bring the SI system to communication between information systems. Various virtual systems bring significant challenges to the management of measurement accuracy. The accuracy requirements for the frequency and absolute timing of electrical and optical signals are becoming increasingly stringent.

Recent acts of sabotage to cut undersea data cables, as well as attacks on Ukraine’s metrology facility during the war in Ukraine, show that a system of standards centralized in one physical location is too vulnerable. Exceptional circumstances weaken information and logistics connections with the outside world. That is why it is all the more important that we in Finland are able to verify the measurements of our industry even in exceptional circumstances.