Pillar 1 of 7 · The invisible force

Time

Before clocks, before names for days, there was duration: the interval between a shadow's edge and its return.

Timescale

Each step is an order of duration, not a tick of a clock.

A tropical year
Duration1.00 years
In heartbeats3.94e+7
Fraction of cosmic time7.25e-9%

If the age of the universe were compressed to a single tropical year, recorded human history would occupy the last few seconds of 31 December.

Time is not a thing we found in the world. It is the name we give to change that will not reverse. A torch guttering in a cave, a pulse, a river — each is a clock because each is a sequence that cannot be undone.

Physics later split the word. Newton's time was a universal stage. Einstein's was local, elastic, braided with space. Quantum theory added a stranger claim: that some sequences exist only when they are recorded. The documentary's first episode returns to the cave because that is where the question is still honest.

This companion treats Time as the first pillar: a scale from a heartbeat to the age of the universe, so the other six pillars have something to measure.

In the series