Current Definition of Time

In encyclopedias, one cannot really say that time is defined, and when it is, it is closer to a sequence of events than to the measurement of time — its chronometry. A year, a day, a minute… This chronometry is only possible relative to precise references.

References which do not exist in the universe. This must be clearly understood.

Because that means that cosmic Time does not exist at all.

Succession

What does exist, however, is Succession. 

This sequence of events gives the idea of past and future. A glass that breaks cannot reassemble itself. Indeed, once it has broken, we can say: it was intact (past), and now (present/future) it is shattered.

This succession gives the impression of time passing, but without chronometry it is not the useful time indicated by our watches; it is simply a Succession of events.

The confusion is easy, but the difference is immense. Our prehistoric ancestors saw that days followed one another, that the dead did not wake up, that water flowed in one direction in streams and rivers. But they had no watches. They did not measure time. They had no appointments at 3:00 p.m. At best, they could agree to meet at sunrise or sunset — nothing more.

And it is precisely this reference — sunrise or sunset — that makes time measurement possible. The circadian periodicity is the only temporal reference that exists for humans, and it is not cosmic.

the Circadian Periodicity

What we wear on our wrist is the calculation of this periodicity, divided into units of measurement: hours, minutes, seconds. Time zones are interpretations of this periodicity, based on the dance of the Sun and Earth for each latitude.

People wake with the day in America, and in France as well — at the same local time, but not at the same moment. Universal time therefore does not exist. On the contrary, it exists only for this pin‑head called Earth, hidden among trillions of football fields. Worse still, it exists only for the humans who live on it. Animals do not care.

Time zones are the best evidence of the circadian periodicity as they measure the sleep and awake time of humans all around the world.

the Mistake

Chronometric time is a key value for many physical parameters and equations. It is the basis of acceleration and velocity, which in turn allow us to calculate force, thrust, and so on. So total was the misunderstanding even for Einstein, who named his “spacetime,” whereas its true name should have been closer to “space‑succession”. ΛCDM itself, when it calculates the age of the universe as 13.7 billion years, speaks of years that did not exist before the appearance of the Earth and the Sun. This number is therefore completely arbitrary and carries no real meaning.

The universe has no duration.

• It does not need to wake up in the morning, there is no cosmic morning at all, no day, no night !
• It does not need to rest.
• It has no sequences to measure, and no appointments to keep.
• Velocity is not measurable. Comparable between two events at best, but not measurable. So light velocity is a human measure between two human references.

The Light Years

Since distances are expressed in kilometres travelled by light in a year, we assume that cosmic distances are a question and a function of time. This is why this passage is of immense importance for the understanding of cosmology — or rather, for its misunderstanding, because this enormous mistake calls the whole of it into question.
The light-year is a terrestrial unit. It is not a cosmic unit. And a year is defined by the circadian periodicity of life on Earth — nothing more.
The same is true of the speed of light. It is usually presented as a universal constant — 299,792,458 metres per second. But the metre and the second are terrestrial units. The second is defined by the circadian periodicity of life on Earth. The metre is defined by the distance light travels in 1/299,792,458 of a second. Each unit refers back to the other, and both refer back to the Earth.

In the cosmos, there is no second, no metre, no observer, and no clock. The speed of light is therefore not a constant of the universe. It is a number calculated between two terrestrial references. It has no measurable value in space.

This has consequences. The distances expressed in light-years are calculated from this speed. They inherit its terrestrial origin. The 3.3 billion light-years of the Big Ring, the 13.8 billion years of the universe, the 380,000 years after the Big Bang — all of these numbers are built on a speed that has no cosmic reality. They are not measurements. They are extrapolations from a local convention.

If light has no measurable speed in the cosmos, then it has no universal value — no equal value everywhere. The speed of light is a terrestrial parameter, and its extension to the universe is an unjustified projection.

A dramatic and revolutionary conclusion

This subtitle is not an expression of presumption, but of equivalence: if general relativity was a revolution, calling it into question must be considered one as well. 

If cosmic distances are a function of time, and if time has no cosmic reality, then neither do distances. And if distances are not measurable, the structure that organizes them — spacetime — is not measurable either. This does not invalidate general relativity as a local tool. It invalidates its extension to the universe. The cosmological solutions of general relativity rest on coordinates that have no physical counterpart. They are mathematical constructions applied to an object — cosmic spacetime — for which no observation provides evidence. 

Now that this is clear, you can understand how encyclopedias like Wikipedia and Universalis repeat absurdities.

Here is what Universalis says:

The Encyclopædia Universalis, in its article on time, begins with a quotation from Saint Augustine: "If no one asks me, I know what time is. If someone asks me, I no longer know." (Barreau & Costa de Beauregard, 1999; my translation)

And it adds: "Despite all the reflections made and the knowledge accumulated about it, and by many specialists, the much-scrutinised face of time remains, in some respects, that of a sphinx."

The article then explains that physicists have defined time operationally — that is, by what it measures, not by what it is. The second is defined as 9,192,631,770 periods of a caesium-133 transition. The metre is defined as the distance light travels in 1/299,792,458 of a second. Each unit refers back to the other.

So the definition of time rests on human conventions. On the caesium atom. On the Earth. On the Sun.

Why "Convention" Is the Wrong Word 

Universalis describes time as defined by convention. But this is not exact. The circadian periodicity is not a convention. It is a constraint. It is imposed on every living being on Earth. Day and night exist. Sleep and waking exist. The human body is regulated by this cycle. No one chose it. It is there, before us, independent of us.

And this is the essential difference. A convention could be extended to the universe. A constraint tied to the Earth cannot. The universe has no day, no night, no waking, no sleep. The units of time come from a cycle that exists only on Earth, for the life that inhabits it. They cannot be projected onto the universe.

Here is what Wikipedia says in its definition of time (retrieved 3 October 2026)

Time is the continuous progression of existence that occurs in an apparently irreversible succession from the past, through the present, and into the future. Time dictates all forms of action, age, and causality, being a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in conscious experience. Time is often referred to as the fourth dimension and the temporal dimension, in addition to the three spatial dimensions.

Time is primarily measured in linear spans or periods, ordered from shortest to longest. Practical, human-scale measurements of time are performed using clocks and calendars, reflecting a 24-hour day collected into a 365-day year linked to the astronomical motion of the Earth. Scientific measurements of time instead vary from Planck time at the shortest to billions of years at the longest.

Measurable time is believed to have effectively begun with the Big Bang 13.8 billion years ago, encompassed by the chronology of the universe. Modern physics understands time to be inextricable from space within the concept of spacetime described by general relativity. Time can therefore be dilated by velocity and matter to pass faster or slower for an external observer, though this is considered negligible outside of extreme conditions, namely relativistic speeds or the gravitational pulls of black holes.

Explanations for strikethrough expressions

1. measurable time: There is no cosmic measurable time.
2. Big Bang: The Big Bang never happened for all the reasons detailed in the article on ΛCDM 
3. 13.8 billion years ago: The universe has no age and no duration
4. spacetime: This term is a mathematical conjecture without a physical definition and the worst is that it has no meaning.
5. If cosmic time does not exist, then time dilation — as it is described in relativity — cannot be a dilation of a universal time. It can only be a local effect, relative to a local observer and a local clock.
6. If there is no cosmic time, then there is no universal reference against which a dilation could be defined. Each clock dilates relative to another clock. There is no global frame. So the statement "time dilates" should be read as: the rate of local processes changes depending on the local conditions. Not that a substance called "time" stretches or contracts.
7. black holes: They have never been observed and a detailed explanation of what they are is available in Black Holes 

Conclusion

The conclusion is very simple.

• What exists everywhere is succession — the irreversible order of events.
• What exists is chronometry — the local measurement of duration, based on the circadian periodicity of life on Earth.
• What does not exist is cosmic time — a universal clock that would measure the universe itself.

References

Wikipedia contributors. (2026, October 3). Time. In Wikipedia. Retrieved October 3, 2026, from https://en.wikipedia.org/wiki/Time 

Barreau, H., & Costa de Beauregard, O. (1999). Temps. In Encyclopædia Universalis. https://www.universalis.fr/encyclopedie/temps/