What is time?

And yet this individual, or rather this crowd of individuals, is not to blame. Simply responding to a concrete need to forecast events, each of them has, according to his or her era and knowledge, contributed to the development of our societies. From the ancient Egyptian who needed to know the right time to sow wheat, to the sailor who needed to plan his sea voyages, knowledge of the weather has become indispensable to everyone.

Measuring time involves determining the time elapsed between two repetitions of the same event, and counting the number of times this happens. The complexity lies in our ability to accurately measure the regularity of this repetition. Simply put, are we able to measure the time elapsed between two sunrises, and secondly, can we establish that this duration is the same each time the sun appears? If so, we can use this event as a reference for calendars, ephemerides and other ‘time stamps’.

If not, we need to find a more reliable event. The sun, stars, vegetation and climate are all indicators of the passage of time. With the help of technology, it is the analysis of elementary particles that now provides the best references.

But time cannot be summed up as a simple counting of sheep; it is also a source of intense reflection for scientists and thinkers of all stripes. And the astonishing physical properties attributed to it would make a gymnastics teacher’s day: compression, distortion, flexion, extension are all capacities that intrigue and fascinate at the same time.

So the mystery of his abilities remains, and only one essential question, at the root of all questions about time, can be answered today: “Why does time go by faster on vacation? “. Well, it’s precisely because we don’t worry about it on vacation that time passes more quickly!