Time is only there when we notice it.
Albert Einstein has changed the way we think about time when he introduced his theory of relativity. He stated that time is not a constant but variable and depending on the way we perceive it we get different results.
A very famous example of this theory is the twin paradox. Imagine identical twins one of them is on Earth while the other is on a space ship traveling at the speed of light. The traveling twin will notice his time as passing normally but by the time he return to Earth he will find his twin has aged and many years has passed by.
So what is time?
It is a measurement component for duration of things, comparing events and quantifying rates of change.
Counting time is subjective
An hour could feel like a minute or an eternity depending on how we spend it. We all noticed that time flies when we are enjoying it but slows down when we are bored.
A child day is different than an adult, it start slow but keeps getting faster and faster the more we age. An infant count the day as wake up, eat, play and sleep. The more he or she grows the more things in a day are added; school, homework, exams, marriage, job, children…etc. Days aren’t getting faster, only the way we count them that is getting different.
What if we live on another planet?
A day on Mars is equivalent to one day and forty minutes on Earth and a year on Mars is equal to 687 Earth days. If someone said “I will come in an hour” it is equal on both planets but “I will see you after two days” it will start to get confusing and for any plans to be done in a year will be so off without referring to which time frame.
A being lifespan can dramatically alter the perception of time. The average life expectancy for humans is 82 years, we know that a one year old human is an infant at the beginning of his or her life and an 80 years old is an elder and nearing the end of his lifetime. A housefly, in the other hand, lives up to 28 days. A day to a housefly is like a year to us but a year to a fly is like an eternity.
The lesser you live the more the time matter.
An immortal has no concept of time. Years may seem like seconds, millennia is merely like minutes and an eternity like yesterday.
We are not immortals but our memories could last forever in our children and grandchildren, in history books and on our life time works.
So please cherish your time, use it wisely and most of all enjoy every moment.