The Order of Time

by Carlo Rovelli

I stop and do nothing. Nothing happens. I am thinking about nothing. I listen to the passing of time. This is time, familiar and intimate. We are taken by it. The rush of seconds, hours, years that hurls us toward life then drags us toward nothingness. . . . We inhabit time as fish live in water. Our being is being in time. Its solemn music nurtures us, opens the world to us, troubles us, frightens and lulls us. The universe unfolds into the future, dragged by time, and exists according to the order of time.

Because the mystery of time is ultimately, perhaps, more about ourselves than about the cosmos.

The ability to understand something before it’s observed is at the heart of scientific thinking.

we learn that the things that seemed self-evident to us were really no more than prejudices.

He looked for a plausible explanation and found one by imagining that the sun and the Earth do not attract each other directly but that each of the two gradually acts on that which is between them. And since what lies between them is only space and time, he imagined that the sun and the Earth each modified the space and time that surrounded them, just as a body immersed in water displaces the water around it. This modification of the structure of time influences in turn the movement of bodies, causing them to “fall” toward each other.4

There is no “truer” time; there are two times and they change relative to each other. Neither is truer than the other.

Times are legion: a different one for every point in space. There is not one single time; there is a vast multitude of them.

“proper time”

Physics does not describe how things evolve “in time” but how things evolve in their own times, and how “times” evolve relative to each other.

The difference between past and future, between cause and effect, between memory and hope, between regret and intention . . . in the elementary laws that describe the mechanisms of the world, there is no such difference.

Rebellion is perhaps among the deepest roots of science: the refusal to accept the present order of things.

Perhaps poetry is another of science’s deepest roots: the capacity to see beyond the visible.

The link between time and heat is therefore fundamental: every time a difference is manifested between the past and the future, heat is involved.

It is the only equation of fundamental physics that knows any difference between past and future. The only one that speaks of the flowing of time. Behind this unusual equation, an entire world lies hidden.