On a large table wrapped in hundreds of cables, a maze of mirrors and lenses bounces and directs a thin beam of laser light. It is crowned with silver capsule, which contains 40,000 of the chilled sternumium atoms into a site of absolute scratch. This precise edifice is a visual watch, one of the most accurate hours in the world.
Such tools are not fully designed to be carried – which makes it a bit surprising that one of these devices at the German National Standards Institute mobilized them in a trailer and sent him down the highway. It was the beginning of a risky journey: the bad tremor can disrupt the exact tick rhythm. But it was necessary.
It was because, in 2022, scientists agreed globally that we must start working to redefine the second based on the latest and largest time to save time: visual watches. However, this means collecting many of the best samples in the world for comparison.
It has proven to do so a big challenge, but it will definitely be worthy of trouble. A new definition of the second will be a deep result of all the other measurement that scientists use to describe nature, from speeds to masses and more. Our efforts to select it more precisely, then, will wander through our entire point of view of the world. “This was the first global comparison …