BY: Arjit Mishra
Time we can't see it, can't hear it, but we can feel it or more specifically we can observe it.
Before Einstein Scientists used to believe that space and time both exist independently; Any change in Space doesn't effect Time. According to Newton "Time is Absolute" means in every place and every condition it remains same.
But Einstein has it's own definition of Time, He believed that Space and Time are connected to each other and do not exist independently. He defines Time to be Relative instead of Absolute, means it is never same for everyone, it passes differently for different conditions. In the relativistic context we can't separate Space and Time.
Moreover speed of propagation of time depends upon object's velocity and it's Gravitational Field.
If my Gravitational field and velocity is different from your's then Time will not be same for me and you.
An Increase in velocity and Gravity will decrease the speed of time propagation.
Let us understand this with the help of an Example :
As Saturn is bigger than Earth then it's Gravity is also bigger than Earth and because of this Time propagation speed will be less on Saturn as compare to that of Earth.
If a Human/Animal somehow able to live on Saturn then he/she/it would live longer than a person/Animal of same age on earth because Time would pass differently for both of them.
Similarly If we are travelling in a spaceship whose velocity is very high then time propagation speed would be slow as compare to outer world. This clearly indicate that Space and time are interconnected. The concept of Time dilation and Length contraction is very amazing but I would talk about them on my later blogs.
According to Einstein speed of Light is fixed for any inertial frame. As we tend towards the speed of Light, Time propagation speed tends to Zero. Specifically at the speed of Light Time completely stops. To explain the events happening in space and time a Mathematical model is there which we call "Space Time Continuum".
Before understanding Space-Time we have to understand Space and Time separately :
Everything present around us is a part of Space. To define the position of object in space we take the help of 3-D Graph which has X, Y and Z axis which depict the length, width and height/depth of an object and makes up the 3-Dimensional object.
While in the case of Time it would be difficult for us to define it, but we know that it always moves in one direction that's why we can say that it is our 4th Dimension.
Time we can't see it, can't hear it, but we can feel it or more specifically we can observe it.
What is it ? is it somehow related to Space ?
But Einstein has it's own definition of Time, He believed that Space and Time are connected to each other and do not exist independently. He defines Time to be Relative instead of Absolute, means it is never same for everyone, it passes differently for different conditions. In the relativistic context we can't separate Space and Time.
Moreover speed of propagation of time depends upon object's velocity and it's Gravitational Field.
If my Gravitational field and velocity is different from your's then Time will not be same for me and you.
An Increase in velocity and Gravity will decrease the speed of time propagation.
Let us understand this with the help of an Example :
As Saturn is bigger than Earth then it's Gravity is also bigger than Earth and because of this Time propagation speed will be less on Saturn as compare to that of Earth.
If a Human/Animal somehow able to live on Saturn then he/she/it would live longer than a person/Animal of same age on earth because Time would pass differently for both of them.
Similarly If we are travelling in a spaceship whose velocity is very high then time propagation speed would be slow as compare to outer world. This clearly indicate that Space and time are interconnected. The concept of Time dilation and Length contraction is very amazing but I would talk about them on my later blogs.
According to Einstein speed of Light is fixed for any inertial frame. As we tend towards the speed of Light, Time propagation speed tends to Zero. Specifically at the speed of Light Time completely stops. To explain the events happening in space and time a Mathematical model is there which we call "Space Time Continuum".
Before understanding Space-Time we have to understand Space and Time separately :
Everything present around us is a part of Space. To define the position of object in space we take the help of 3-D Graph which has X, Y and Z axis which depict the length, width and height/depth of an object and makes up the 3-Dimensional object.
While in the case of Time it would be difficult for us to define it, but we know that it always moves in one direction that's why we can say that it is our 4th Dimension.
If we combine the space and time then we have presented with 4-Dimensional Space-Time.
as space-time is 4-Dimensional and unfortunately we can't visualize 4-D , but we can visualize it through a 2-Dimensional Graph :
Here X axis defines the space and Y axis defines Time, since Space and Time are connected to each other Anything that moves in Space It also moves in Time.
Physicists observe this world frame by frame Let us know how ?
When we throw a stone into pond we can clearly observe the formation of ripples in it, This is a very common Event that we have observed at least once in a lifetime.
Now let us observe it frame by frame :
When we throw a stone instantly nothing happens but after 1 second one ripple is formed, after 2 seconds two ripples are formed and after 3 seconds formation of three ripples can be observed.
When we see it with full concentration a cone can be observed, Basically this cone is the Locus of light through Space-Time, If we reverse the direction of time then we could obtain the opposite cone which describes the events in past. This cone is specifically called as Light Cone.
EINSTEIN SAID :
"For us Physicists, the separation between past, present and future is only an illusion, although a convincing one"
Which means past, present and future always exist, propagation of Time is just an Illusion.
A question must be arising in your mind that "why the world seems to moving ?"
The answer this question is very philosophical, answer totally depends upon principle of video. when we play a video it seems to be moving but actually it is the combination of sequential images slide showed in such a way that the time interval between any two sequential images is very less. but actually there are number of images/Frames at a same time.
Now what is the Advantage of Space-Time Graph ?
Actually with the help of space-time graph we could determine the position and conditions of various celestial bodies and even Universe itself by drawing Bigger and Smaller graphs appropriately.
"Our virtues and our failures are inseparable, like force and matter. When they separate, man is no more."
Nice explanation and good content
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