TIME

Time and space are the two main features that describe our existence. Every second of our lives, we are located somewhere. We cannot describe our activities separately from time and space. After the question "When?" comes immediately the question "Where?"

Time remains one of the most mysterious aspects of the world in which we live. It connects our existence with the past, the present and the future in one continuous process. Many philosophers and scientists are still trying to define the concept of time.

Time is so fundamental to our lives that we cannot imagine our everyday existence without measuring it, as if life were one continuous process. The human brain is designed in such a way that it feels more comfortable and secure when everything is structured and organised. Without time, there would be great chaos. We need time to plan our lives and make them more organised.

Time management is important in our daily lives. We tend to think that we can manage time. Yet time moves only forwards, never backwards. 

In many works of fiction, the plot includes the invention of a time machine. A time machine enables people to relive past periods and eventually change future events. It gives people the illusion that we can control time. This is a powerful illusion because the time we measure and the way we control it are not the same as time itself in the vast universe.

None of our definitions will ever be able to describe fully the true nature of time. However, scientists believe that memory formation is the basis of the human perception of time.

The beginnings of civilisation on Earth required knowledge of the seasons, and the mysteries surrounding the length of the year, the day and the month gradually became subjects of study.

All the world's religions gave time a central role, whether through astrology, stories of creation, cyclical views of history or ideas of eternity.

From the beginning of recorded history until the present day, enormous effort has been devoted to creating devices that measure time with ever-increasing accuracy.

Historically, people invented several ways of measuring time, or chronometry. This developed in two different forms: the calendar, a mathematical tool for organising intervals of time, and the clock, a physical mechanism that measures the passage of time.

In everyday life, the clock is used for periods shorter than a day, whereas the calendar is used for longer periods. Today, our phones display both clocks and calendars at the same time.

Time passes continuously, and we follow its passage with clocks and calendars. Yet we still cannot say exactly what happens when time passes.

Time is represented through change, such as the circular motion of the Moon around the Earth. The passing of time is closely connected with the concept of space.

As far as the universe is concerned, time had a beginning. According to the General Theory of Relativity, both space and time began with the Big Bang about 13.7 billion years ago. Before that, all matter was compressed into an unimaginably tiny point. That point also contained the matter that later became the Sun, the Earth and the Moon—the heavenly bodies that help us measure the passing of time.

Before the Big Bang, there was no space or time. It is difficult for us to understand how time works. The past is different from the future. We remember the past, but we do not remember the future.

There are things that cannot go backwards. For example, when you turn an egg into an omelette, you cannot turn the omelette back into an egg. We are born young and grow older, but this process does not happen in reverse.

The arrow of time points only forwards. It is something we can measure, but we cannot feel directly. Science, philosophy, religion and the arts all define time in different ways, yet the system we use to measure it is relatively consistent.

Clocks are based on seconds, minutes and hours. But what exactly is time?

Physicists define time as the progression of events from the past through the present and into the future. Essentially, if a system does not change, it is timeless.

Time can be considered the fourth dimension of reality, used to describe events in three-dimensional space. It is not something we can see, touch or taste, but we can measure its passage.

In other words, the universe cannot return to exactly the same state that it was in at an earlier moment. Time cannot move backwards.

In classical mechanics, time is the same everywhere. Synchronised clocks remain in agreement.

Some physicists argue that time is an illusion: our intuitive perception of its flow does not correspond completely to physical reality. According to this view, reality is a complex network of events onto which we project the ideas of past, present and future.

Time plays a fundamental role in the organisation of the universe. Some philosophers even argue that only present objects and present experiences are real.

There is also something that we call biological time. It is defined by the regular biological processes within us and by the signs of ageing. Our heartbeat is regular, our breathing follows regular rhythms, and our lives are organised around regular cycles of sleeping and waking.

Time has played a central role in mathematics from its very beginnings and has been studied from many different perspectives.

Mathematics almost certainly began with the study of time, particularly with the need to record sequences of events. Understanding the seasons was essential for the successful cultivation of crops.

The natural timekeepers in the sky are the daily movement of the Sun and the monthly phases of the Moon. Knowing the length of a year was vitally important, although it was much less obvious than observing the daily and monthly cycles. This led people to develop methods of calculation.

It was also necessary to count days and months, and this gave rise to calendars.

The earliest evidence of timekeeping dates back about 20,000 years. Marks found on sticks and bones in Europe are believed to record the number of days between successive new moons.

Many ancient calendars were created. As one example, let us briefly consider the Egyptian calendar from around 4500 BC.

Dividing the year into months was natural but complicated because there is not an exact whole number of months in a year. Similarly, dividing the month into days presented difficulties for the same reason.

A day itself was a long period of time, and there was a clear need to divide it into smaller units, although it was not immediately obvious how this should be done.

Around 3000 BC, the Sumerians divided the day into twelve periods and each of these periods into thirty parts.

About one thousand years later, the Babylonian civilisation, which developed in the same region as the earlier Sumerians, divided the day into twenty-four hours, each hour into sixty minutes, and each minute into sixty seconds.

It is this Babylonian system that gave us the units of time that are still used throughout the world today.

In mathematics, time is considered to be the ongoing sequence of events. The basic unit of time is the second. There are also minutes, hours, days, weeks, months and years.

We measure time using clocks. Time is usually shown in the format Hours. There are two common systems: the 24-hour clock and the 12-hour clock.

In mathematics, we learn how to tell the time and how to add and subtract time, which means adding or subtracting hours and minutes separately.

Time in mathematics also includes converting between seconds, minutes, hours, days, weeks, months and years. Solving problems involving time may require adding and subtracting time intervals or multiplying and dividing to convert between different units of time.

Converting between units of time requires an understanding of how many smaller units make up a larger one. For example, there are 365 days in a year, approximately 52 weeks in a year, 7 days in a week, 24 hours in a day, 60 minutes in an hour and 60 seconds in a minute.

Mathematics studies time together with other compound measures. A compound measure is a measurement that combines more than one quantity.

For example, speed is measured using the formula:

Speed = Distance ÷ Time

Therefore, if we need to calculate speed or distance, we also need to know the time. Calculations involving distance, speed and time can be carried out using mathematical formulae.

Here are some activities for you:

Activity 1: If you had a time machine, which historical period would you like to visit? If you had the power to change some historical events, which ones would you change, and why?

Activity 2: Can you name a few different calendars used to measure the year?

Activity 3: Can you make a list of ten sayings, proverbs or idioms containing the word time? Can you translate them into English? Did you notice any changes in their meaning?

In life, we all travel through time. For example, we travel one year between each birthday.

When we experience happy moments, it seems that time passes very quickly. When we go through difficult times, it feels as if they will never end.

Time is something of which we never seem to have enough. You cannot buy it in a shop, and you cannot borrow it.

Our whole life depends on time.

Sometimes one happy moment can stay with us forever. We never forget the difficult times either. They become lessons—sometimes painful ones—that remain with us for the rest of our lives.

We need to treasure every day as something that will never happen again. Every day reminds us how short our time on planet Earth is and how much we need to appreciate it.

We should use our precious time here to spread goodness.

We have a habit of always looking towards what is waiting for us in the future. Very often, we divide ourselves: physically we are here, but spiritually we are already living in the future. As a result, we are nowhere.

Perhaps we need to develop the habit of living more in the present moment so that we can be more useful and devote all our energy and effort to making our lives better now. Because now is the future.

We have spoken about physical and biological time, but there is also something called psychological time. It is personal and subjective. It is as if, within the vast universe, there are billions of other miniature universes created by us, human beings.

According to this kind of time, we follow the rules of the heart. The time in our heart moves in a different space from the time outside us. Our heart loves daydreaming, which is often made possible through travelling in time.

Some people say that time is measured not by clocks but by moments. We need to enjoy every moment because it will never come again.

There is a well-known saying: An inch of time is an inch of gold, but you cannot buy that inch of time with an inch of gold.

Very often, when we do not have answers to important events in our lives, we leave everything to time, hoping that it will resolve things for us.

Does time really heal? Or do we simply become accustomed to the pain? The answer is different for everyone.

In our everyday lives, we should pay more attention to our own time management. How do we spend our day? Are we doing something meaningful for ourselves and for others? Are we the creators of the events in our lives, or are we simply waiting for time to do something for us?

There is not enough time to waste. Through better time management, we should use our days to do creative things that can help make the world a better place, full of beauty and peace.

No time should be wasted because it is so precious.

Will time ever end? Will there be another Big Bang, but in reverse?

The answer to these questions is unknown.

Only time will tell.

(E. S. Lyubenova, LoveMaths Story for My Students)