Time. We all know it. We all feel it’s passing and are bound by its earthly laws. Time is integral to every culture, every place, every epoch. It is known by many names: Father Time, Chronos, Zaman, Aion, Tempus, Dura, Nara, and Toki. We are familiar with time too. We see its effects: time is a thief, time is a river, time is a journey, time is a teacher, time is a healer, time is a mirror, time is money, time flies. We think of time as flowing consistently from the past, through the present and into the future. We measure time through clocks, calendars and chronographs. We have atomic clocks that measure time to within a minute fraction of a second. Time is on every electronic device we have. It regulates our lives and controls every waking second. 

And yet, scientists do not know what time is or how it works. Physicist Carlo Rovelli said: “time is like holding a snowflake in your hands: gradually, as you study it, it melts between your fingers and vanishes.” When time is put to the sword of scientific scrutiny, it loses substance and disappears. One of the best ways of studying time then, is to see its effects; and the most useful way of doing that is by measuring heat. 

Heat and time seem inextricably interwoven. The difference between past and future exists only when there is heat. Without heat, the future behaves exactly like the past. Without heat, without friction, things would move indefinitely. Bizarrely however, the movement of heat from a hot object to a cold one is not an absolute law, it is only statistically probable that this happens, which means there is nothing that corresponds to the notion of the ‘now’. The idea of a present that is common to the whole universe is a subjective illusion; the universal ‘flow’ of time is a generalisation. All of our memories, our whole consciousness, is built on statistical phenomena and thermodynamics. And yet, statistics and heat are not time itself.

What we think of as time is actually better described as entropy. Entropy, or heat and energy, is defined as a measure of a system’s chaos or unpredictability level. Entropy always increases over time, as systems move to higher states of disorder. We know this. We get old. We break down. We die. This is time as we know it. But this increase in entropy, this ageing, is not actually an increase in chaos, it is an increase in the number of possible arrangements or states within a system. It means we aren’t breaking down, we are diversifying. We are becoming more than. Our possibilities are increasing, and we have the potential to become so much more than what we know. We can transcend. If only we can understand how. 

 Sources: Seven Brief Lessons on Physics, and The Order of Time, by Carlo Rovelli.