Time is not a simple thing that we take it to be, it is pregnant with meaning and mystery. Mankind perishes speedily by thinking of time as real. "The little time I spend in asking – Is there time at all? – has revealed to me the perfect Peace, the very Deity Himself," observes Thirumular, a medieval Tamil Shaivite saint, in Thirumandiram. He asks, "Do you know that time vanishes when its origin is sought for? What then is the use of limiting yourself to it?"

What, then is time? St Augustine, in his Confessions, has revealed a plausible answer. "If no one asks of me, I know: if I wish to explain to him who asks, I know not." Augustine accepted the reality of only the present time, denying any validity to past and future time. But then there are three presents: the present of things past in memory, the present of things present in sight, and the present of things future in expectation. For TS Eliot, in Four Quartets, "Time present and time past/ Are both perhaps present in time future/ And time future contained in time past/ If all time is eternally present/ All time is unredeemable."

For many physicists, including Einstein, time is not fundamentally real but merely a figment of our limited perception of reality; its distinction between past, present, and future is an illusion. At the deepest foundations of nature, time is not an irreducible element or concept required to construct reality. Everything that has ever happened in the past, or will happen in the future, is technically happening simultaneously in the Now. Although there is no consensus on the definition of time, there is no disagreement about its measurement. Aristotle spelt it out as "the calculable measure of motion with respect to before and 'afterness'." This idea of time as a fixed sequence of events survived until Einstein defined space and time as different aspects of the same entity called spacetime. In other words, there is no absolute time, "My time and your time are different depending on how fast we are moving from each other." The faster we move, the greater the magnitude of the time dilation we experience.

On a psychological level, as Henry van Dyke said in Music and Other Poems, "Time is too slow for those who wait, Too swift for those who fear, Too long for those who grieve, Too short for those who rejoice, But for those who love, time is eternity."

Throughout history, mankind has tried to measure time with various methods. At first, it was the seasons, hot or cold, later the year was divided into months, weeks, and days. Sumerians invented the system of Time by dividing hours into 60 minutes and days into 24 hours. Babylonians divided the year into 12 equal parts and the day into 24 hours according to the solar calendar. According to the ancient Egyptian priests, time was the disappearance of energy; in other words, the transformation process of energy that symbolised the eternal creator.

Time is an intangible element of our daily life, though describing its fundamental nature is much harder. So, let not the sands of time get in our lunch: "Time goes, you say? Ah! No, time stays, we go."