Time is everywhere in our lives, and its concept is deeply rooted in our existence. You know how old you are, how long a day is, or how long it will take you to go from one place to another. Time, in our everyday life is simply the way we measure the duration of events. Of course, time is also extremely important in physics: it is the fourth dimension of spacetime, used to measure an object’s speed or frequency. Scientists now suggest that this concept is incorrect, and describe time as a measure of the numerical order of change; time itself is not a fundamental entity.

Amrit Sorli, Davide Fiscaletti, and Dusan Klinar from the Scientific Research Centre Bistra in Ptuj, Slovenia, explain that time (*t*) has only a mathematical value, and no primary physical meaning. We usually consider time as an absolute physical quantity, but the scientists explain that we never really measure *t*: we measure an object’s speed, frequency, etc., but not *t* itself. What is really measured is the tick of a clock together with the motion of an object, which are then compared to measure the object’s speed or frequency.

Does it mean that time doesn’t exist? No. This view suggests that our usual 4D spacetime made of three dimensions of space and one dimension of time, is rather made of four dimensions of space. In short, the Universe is timeless.

Here, time is viewed as being the numerical order of material change. The scientists illustrate their concept with the motion of a photon. As the smallest distance a photon can cover is the Planck distance, the corresponding Planck time is considered to be the fundamental unit for measuring the numerical order of photon motion. In space, “before” and “after” exist only as a numerical order.

The three researchers write in their paper: “Minkowski space is not 3D + T, it is 4D”. This has the advantage to better correspond to the physical world: a 4D space is a medium in which immediate information transfer, as in EPR-like experiments or quantum tunneling, has a numerical order equal to zero. This cannot be explained in the usual concept of spacetime where all physical phenomena happen in space and time.

Their model also gives a solution to Zeno’s paradoxes. For their demonstration, the scientists used the paradox of *Achilles and the Tortoise*: Achilles is in a footrace with a tortoise, and gives it a head start of 100 meters. Although Achilles runs much faster than the tortoise, he will never be able to surpass it. Assuming Achilles runs 10 times faster than the tortoise, when Achilles reaches the tortoise’s starting point, the tortoise will be 10 meters ahead. It will then take Achilles some further time to run that distance, by which time the tortoise will have advanced farther; and then more time still to reach this third point, while the tortoise moves ahead.

Of course, the fact that Achilles can never overtake the tortoise is blatantly false. In the scientists perspective, motion only exists in space, not in time. As Achilles and the tortoise move through space only, Achilles can surpass the Tortoise in space, although he won’t in absolute time.

Finally, this interpretation of time has another important consequence: time travel is simply impossible. Time being the numerical order of an object’s motion in space, an object only moves in space, not in time. I will leave the final word to Einstein who once said:

“Time has no independent existence apart from the order of events by which we measure it”.

**References**

- Amrit Sorli, Davide Fiscaletti, and Dusan Klinar.
**Replacing time with numerical order of material change resolves Zeno problems of motion**.*Physics Essays*, 24, 1 (2011). DOI: 10.4006/1.3525416 - Amrit Sorli, Dusan Klinar, and Davide Fiscaletti.
**New Insights into the Special Theory of Relativity**.*Physics Essays*24, 2 (2011). To be published.