What is time?

This post is inspired by an article on Quartz which talks about Carlo Rovelli’s views on the concept of time. Full article is linked below.

“There is no time variable in the fundamental equations that describe the world”

Carlo Rovelli

Carlo Rovelli has spent his life studying time. His book, The Order of Timeis about how humans experience the passage of time. He argues that chronology and continuity are humans’ own ‘constructs’, created to allow us to make sense of our existence.

That being said; is “time” a universal truth? Consider one of my favourite films, Interstellar, where Matthew McConaughey finds himself in a tesseract; this was an incredibly difficult concept to capture on film, and I think it was done really well. Effectively, this is a 4-dimensional space where the 4th dimension is time. In other words, all time is simultaneous and where we are at one particular ‘point’ in time is not a necessarily “mutually exclusive” event. As Rovelli expains it – the universe is made up of countless events – even something trivial such as a rock, is an event which takes place at a rate which we as humans cannot process!

For simple humans like ourselves, the concept of time seems quite ordinary and logical… we have our past, present and future, and things seem to unfold in a sequential, or time-based, and logical fashion. However, the universe is obviously more complex, and most of us cant process information in a way which allows for drastic deviation from our own perceived logic.

You may have heard that the story about the stars we see in the night sky actually being gone? It turns out, the shortest-lived stars may live just 1 or 2 million years total, while others survive for billions to trillions of years – but by and large, every star we can see is almost certainly still alive, contrary to astronomy’s most popular myth. That said, there are a few candidates for stars which may now be dead, but cumulative odds are below 1% that even one star has already died, according to Ethan Siegel in his Forbes article.

Since the concept of time deviation is rather abstract, consider this example to illustrate the point. Light travels at about 300,000 km/s, and since stars are so far away, even the light from the closest stars will take many years to reach the earth. The brightest star is Sirius in the constellation Canis Major, which is about 8.6 light years away; so if Elon Musk crashed a truck full of Tesla cars into it tomorrow, folks on Earth wouldn’t see it happen until about 2030!

With that example in mind, and according to Rovelli, there is no special moment on Sirius which corresponds to the present time ‘here and now’. In my own interpretation, the moment on Sirius that corresponds to earth right now is what someone next to Sirius would have seen 8.6 years ago. What this means is that the concept of the tesseract is supported and there are indeed multiple moments of “time” which exist at any given moment. In other words, you currently would see sirius 8.6 years ago, and that is happening today on earth, but in the past, on Sirius! Isn’t that mind blowing?!

So, why does this matter? Well, tie this back to our beloved hobby with watches. For starters, we have a measure of time – calibrated in to a standard international measure, where one second is defined as follows:

The second is defined as being equal to the time duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the fundamental unperturbed ground-state of the caesium-133 atom

Source: Wikipedia

We humans have created an array of mechanical objects to measure this passage of time, which is quite possibly a figment of our imagination! I think it is worth taking a moment to appreciate the sheer wonder of watches; these micro-mechanical devices using a range of gears, springs, jewels and cogs moving at a precise rate which is defined by an atomic-level of accuracy, in order to measure the passage of time, which unbelievably might actually be something that doesn’t exist! I am laughing out loud, just because of how bizarre that sounds.

Please do share your thoughts, I look forward to hearing them!


PS. You can read the full Quartz article here.

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