What Makes It Tick

Scientists are devising ever-more-accurate methods to measure time:

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Today’s cutting-edge clocks are based on measuring the vibrations of atoms and molecules. The most precise atomic clocks are so accurate that, over a period of time equivalent to the whole history of the universe to date, they would be off by less than one second.

Today’s quantum horologists are looking to improve things further. For instance, it might be possible to monitor atomic nuclei, which vibrate faster than whole atoms.

Despite the scientific advancements, we're no closer to understanding time's essence. However, there is consensus on several of time's properties: [bold added]

Most physicists agree that time had a beginning, and that it is measured from, and indeed came into being with, The Big Bang some 13.8 billion years ago. Whether, how and when time might end in the future is a more open question, depending on different notions of the ultimate fate of the universe and other mind-bending concepts like the multiverse.

(Image from medium.com)

The so-called arrow of time refers to the one-way direction or asymmetry of time, which leads to the way we instinctively perceive time as moving forwards from the fixed and immutable past, though the present, towards the unknown and unfixed future. This idea has it roots in physics, particularly in the Second Law of Thermodynamics, although other, often related, arrows of time have also been identified.

Our extremely precise methods of measuring time are akin to counting the wrinkles in Einstein's brain. We can observe and record all the data we want, but we're no closer to finding out what makes it tick.