What Time is?
We live in the 21st century but still don’t know the real concept of time, So what time is? Is it just an ongoing sequence from present to future or is it nothing, just made by human beings to manage our activity by the measurements which we made and called as sec, hours, week, decades by our convenience and exploring the nature?
I know what you might be thinking now ,
So what is Time? How did it come into existence? If it came into existence, then when and at what time😛? There are lots of questions but not found the answers yet, but few things which we got can help us to understand the time.
Time is still one of the biggest unsolved mystery.
Earlier before1905 the concept of time was very different, everyone was assuming that time is constant for everyone, for a man standing on the moon and one on the earth will be moving through the time in the same way, what does that mean is earlier the thought was “There might be a Universal clock (ageing with the same speed)which the whole universe follow no matter where you are and how much mass you have. Later on in 1905 Einstein published his work, The Theory Of General Relativity, which helped us to understand how time works. In a simple way, the general theory of relativity says that time depends on how slow or fast any entity moves, the time slows more when the entity speeds up and the time gets faster the more the entities slow down. For example, approaching the speed of light, a person inside a spaceship would age much slower than his Twin at home. Which is also called as twin paradox. But the twins will not feel the speed of time they will actually feel normal.
in simple words, if one pair of twin leaves on space in a spaceship during which he travels close to the speed of light while the other remains on earth, then due to the motion of the one in the spaceship Time will run slowly in the spaceship as compared to the one on earth. So, on his (the one who travelled in a spaceship )return on the earth will find that his brother( the one who remains on earth) aged more than himself.
Well, it doesn’t seem or fit in common sense but it's actually true and experimented
One version of the twin’s paradox has been tested experimentally by flying one cesium clock (atomic clock which is very precise) in an aircraft and the other one on the ground and after ‘4’ days scientist found that the Clock which was in the aircraft had recorded slightly less time than that of the ground.
We cant talk about time separately from gravity and space.
Now let’s understand how Gravity affects time.
Imagine our space as a fabric (refer to the above figure), when an entity of a certain mass has been put on it, the fabric bends and the curves are formed. So due to that curve another object having a smaller mass creating the smaller curve around himself is been attracted towards the bigger one. The gravitational field is really a curving of space and time. The (more the mass) stronger the gravity, the more fabric of space curves.
Now the very interesting part is that the fabric which is bend due to mass bends time also.
The matter warps the space as well as time ( Also known as Gravitational Time dilation)
As, more mass the bending of fabric of space-time curve.
I will give you an example for better understanding: For example, if you live near the event horizon (gravity is such high at this place even light cannot escape if you cross this Horizon) for 20 years and come back to earth, you will see that it has been 200 years on earth. (these number of years are not accurate).
There are many theories like one says Time is just Thermal energy of fundamental particles by which we feel the presence of time and few scientists say there is itself a particle of time which destroys itself at every plank second, well still we don’t know many things about it , scientists are still trying to get it from a fundamental level.
Well, there are many things by which we can understand that how time works, these were the few, I hope your perspective of looking towards Time has changed.