Time According to Physics - vol (1)

THE

RELATIVITY OF

TIME According to

“TIME IS AN ILLUSION” Albert Einstein.

PHYSICS

:image by quanta magazine

What Is Time ?

What is Time? The Time at which we wake up or go to school or the relative concept on which our whole day is routine. Is this the definition of time?

Of course not time is a far big concept than these contradictory definitions.

Time In Physics In Physics we define Time as a scalar quantity (a quantity that has no direction) Time actually is beyond reality for 3 dimensional objects as in physics time is defined as a 4 dimensional object and because of this we can’t see, touch or feel time but can only measure it using instruments like clocks.

In Theory of Special Relativity Time Is Defined as Relative quantity (Time is different for everything in the universe) for all. What it means is that before Einstein that is during the period of Newton; Newton defined Time as a constant quantity (Time is same for everything in the universe).

and to oppose this ides Einstein found out that time is relative. So this was actually what time is. Albert Einstein was a great physicists. He not only discovered relativity of time but he also discovered how it different situations time slows down . Let’s discuss about it in the next section

Note: Time dilation is purely based on mathematical solving. In the next chapter I will try to make you understand time dilation theoretically and I will not add any type of physics equation in it. To observe time dilation in real life you first need to have a vehicle which can move to speed of light (which is not possible).

Time Dilation

Special Relativity also introduces a very interesting concept that is ‘Time Dilation’. Time Dilation shows that how time slows down for two different frames of references (seeing the same phenomenon from different places like one from fast moving train and another sees it from a railway embankment) with the help of images I will simply make you understand about time dilation.

We will simply figure out in which frame of reference is the light beam taking more time to reach to its starting position(inertial point).

Lets discuss first B frame of reference in b frame you can see two persons pointed out by a and b, person ‘a’ is stationery and person ‘b’ is on vehicle that can attain the speed of light. There is a light beam inside a tube; tube has mirror at the top and bottom which continuously reflect the light beam up and down.

And this tube is kept on the vehicle. Now consider that vehicle starts to move with the speed of light.

You are the person on the vehicle, How will you see the motion of light in the tube?

For you the light will move from the bottom to the top and vice versa; so in your frame of reference light takes less time to come back to its inertial position (the position from where the light was send out that is the bottom) ok So now we can say light has traveled a straight path and thus it takes less time to come to its inertial position.

Now this is according to you but what about man standing on the railway embankment, how will he experience the same event? Now consider that you are the man standing on the railway embankment that is the ‘A’ frame of reference everything is same as what was happening in the B frame of reference. There is a tube in which light is performing its motion and a man on the vehicle.

Now let’s see what we you will observe.

The vehicle starts moving (at the speed of light) you are seeing the vehicle from embankment now you suddenly look at the light beam in the tube for you the light beam will start from the bottom at point a then it will go to the top at point b and then it again comes back to its starting position at point c so here for you light has not taken a straight path rather it has taken a longer path and thus here you will see that light has taken more time to reach at its inertial position.

And this states that in ‘B’ reference frame light has taken less time and at ‘A’ frame of reference it has taken more time, this states that Time has dilated in the ‘A’ frame of reference and thus this was the simple concept of time dilation explained in Special Theory of Relativity.

Physics contains many of such concepts; it covers the universe from the classical level to the quantum level. It studies the universe from The Big Bang to the Black Holes and also it studies the expanding universe. To understand about more such physics concepts in a very easy and theoretical manner you can visit my YouTube Channel Bright Brains https://www.youtube.com/channel/UCDGr NB9XlKOZZkXVOUQFkfQ/featured You can subscribe to channel for more such content about physics.

Girish Patil,age 15 St, Teresa Convent Higher Secondary School, Jalgaon Maharashtra, India

Source: - Taken from •‘ULOCKING THE UNIVERSE’ By Stephen Hawking •‘A BREIF HISTORY OF TIME ‘By Stephen Hawking •‘RELATIVITY’ By Albert Einstein