An egg lies broken on the floor. Suddenly the flower, the white and the eggshell begin to gather together. The flower regains its circular shape, the white goes around it and the broken eggshell then arranges itself into the original whole.
This sounds strange because everyone knows that a broken egg cannot be made whole again.
That’s because time goes in one direction – forward. But does that have to be the case?
Not necessarily, says physicist Carlo Rovelli .
If we look at the main basic elements of natural laws and phenomena, we can search for time without success. For the smallest particles forward and backward can be the same phenomenon.
And then maybe it would be possible to put a broken egg back together.
Ones do not perceive time
Time passes and it always goes in the same direction – we are going. But for the physicist Carlo Rovelli, time is not a fundamental quantity. Instead, it is ignited by our limited perception of the world.
The future is likely
Nowadays, curious physicists try to approach time in an unconventional way.
Although the passage of time is clear to all of us, physicists such as the Italian Carlo Rovelli are convinced that time is basically an illusion.
Rovelli is only one of many who have tried to gain a better grip on time. One of them was the remarkable Austrian physicist Ludwig Boltzmann.
In 1877, he gave us a slightly better explanation of what separates past, present and future when he came up with an equation for decay – a manifestation of increasing chaos.
We measure not only motion by time, but also time by motion, for they define each other.
Aristotle – Philosopher
Since we always move from the past to the future, for example from a whole to a broken egg and not the other way around, this causes the degeneration to always increase.
This is the case because there are immeasurable differences in how the molecules of the egg are distributed when an egg is broken than when the molecules are in a regular arrangement in a whole egg.
It is thus much more likely that the egg is broken in various ways than that it is whole.
As time passes, it is understandable that events occur in a chronological sequence where the improbable – that the egg is whole – is followed by the probable – that the egg is broken. In theory, it’s not impossible for the egg to regroup and float to the table – it’s just extremely unlikely.
Boltzmann’s theory of decay does not reveal what kind of basic quantity time actually is, but only in which direction it appears to be heading.
It is assumed that the universe started out in an incredible order and over the next billion years its condition became increasingly chaotic.
And then scientists have to deal with one limitation: This only applies to objects that are composed of many atoms.
If scientists instead look at individual atoms individually, there is no optimal direction for time. He might as well walk in any direction.
Einstein erased the present
Boltzmann’s theory does not fundamentally explain time. Such an explanation requires a theory that can accommodate not only our experience of time’s course and direction, but also time as a fourth dimension.
In 1905, the physicist Albert Einstein came to the conclusion that time does not run in a fixed rhythm everywhere in the universe.
With his limited theory of relativity, Einstein showed that the passage of time is determined by the speed of objects, and therefore two clocks will not beat in time if one of them moves faster than the other.
Time is thus another dimension that everyone does not pass through at the same speed.
For us convinced physicists, the distinction between past, present and future is only an illusion and hardly convincing as such.
Albert Einstein – Physicist
And in 1915, Einstein discovered that it’s not just a difference in speed that causes the clocks to go out of sync. With his general theory of relativity, he linked time and space and explained gravity as a curvature in space-time.
All matter in the universe affects both time and space around it, and the closer you are to a heavy object, the slower time goes.
Since time is flexible, we can no longer agree on one “now” and as a result we have no common understanding of what is past and future.
The theory is completely at odds with our intuition, but countless experiments have confirmed it.
Einstein bent time
Newton rejected the ideas of the ancient Greeks and made time uniform and rhythmic. But Einstein’s revolutionary theories warped time beyond recognition.
Newton considered time the same everywhere
Isaac Newton (1643-1727) believed that time runs in a fixed rhythm everywhere in the universe. The passage of time is independent of who measures it, what happens and where it happens. Although everything would disappear, time would continue its march unabated.
A new theory without time
One consequence of Einstein’s theory is that time is not linear but relative and malleable. Carlo Rovelli goes even further in his scholarship. He is working on a theory that integrates Einstein’s theory of relativity with quantum mechanics so that time does not come into play.
In quantum mechanics, nature tends to be broken up into small, finite parts. Rovelli is convinced that this also applies to the bed itself.
In a theory called loop quantum gravity, space consists of finitely small loops – each about 10 -35 meters – which are woven together in an extremely fine-grained network of “space grains”. Smaller sizes simply do not exist in this theory.
In Rovelli’s theory, neither space nor time is a fundamental quantity, but instead something that is the result of the relations between the particles of space. There is no past or future, but only microscopic dimensions that develop in relation to each other.
Time doesn’t really exist. Instead, there are events – like those conceived by the Greek philosopher Aristotle when he said that time only exists as a measure of change, since time would not pass if nothing happened.
When we nevertheless experience the fixed passage of time and are certain of its direction, it is due, according to Rovelli, to our limited perspective and knowledge of the different states of the universe.
We only interact with a small part of the world, so we don’t have to worry about the flexible time of relativity, nor do we see the microscopic network of events in the underlying quantum reality.
If we knew the connection between all events in the universe, we would be beyond time. But in the coarse-grained world, time seems to move forward, despite the fact that it does not exist in the physical laws that describe the universe at its most fundamental.
Time is the cornerstone of existence
Not everyone agrees with Rovelli, for example the physicist Lee Smolin believes that, on the contrary, time is the cornerstone of existence. Everything else in the universe, including space itself and all physical laws, is born of time.
Smolin does not hesitate to call the question of the nature of time the most important in theoretical physics – and despite the fact that physicists do not agree on what time is, they have not dug themselves into their own trenches.
Instead, they exchange ideas in a joint effort to create an all-encompassing physics that also explains time.
They agree that a better understanding of time is crucial if we are to succeed in coming up with a theory of everything. Whether such a clockwork can be found in the universe, time will tell.
