What does Imaginary Time mean?

Imaginary time is not like the Real-time we experience in our day to day life which is classified as past, present and future. It is a very bizarre idea introduced by Stephen W.Hawking.

Imaginary time is right angled to real time. It was introduced to eliminate the theory of Creator of God from the Universe.   

It is used to remove singularities which avoid the laws of physics to break. It can be seen in MINKOWSKI SPACE-TIME model which was adopted by the theory of relativity.

Real-time has a beginning which is called a big bang and an end which is called a big crunch. But Imaginary time has no beginning and no end rather it has a closed surface like a sphere. We do not have a start and end for a sphere.

The imaginary time direction could be from the south pole. As one goes towards the north from the south pole, the latitudes which are uniformly placed inflates and reach the maximum at the equator and again contract to a single point at the North pole. Even though the universe is zero at the poles it would not be a singularity. This helps us to understand the origin of the universe in the imaginary time can be at a random regular point on the spacetime.

We now consider Imaginary time as a new dimension added to the regular time.

Stephen Hawking popularised this concept in his famous book " The Brief History of Time". 

Can purchase this book here:

 https://www.amazon.in/Briefer-History-Time-Stephen-Hawking-ebook/dp/B00351YEZS?tag=googinhydr18418-21&tag=googinkenshoo-21&ascsubtag=_k_Cj0KCQjwxYLoBRCxARIsAEf16-tDBN60xipDXHEAMkuQGIQ4eXGWHz7WxMUx1t-A-u8jh0CSGUd1YAUaAvtyEALw_wcB_k_&gclid=Cj0KCQjwxYLoBRCxARIsAEf16-tDBN60xipDXHEAMkuQGIQ4eXGWHz7WxMUx1t-A-u8jh0CSGUd1YAUaAvtyEALw_wcB

He personally thinks that individual particles can travel through imaginary time and arrive back at an earlier real-time but not that people can travel back in time like in films such as Back to the Future.

Do you agree with him?

Do you think time travel is possible?

Comment below.

All of physics is either impossible or trivial. It is impossible until you understand it, and then it becomes trivial.

What are Gravitational Waves ?

Gravitational Waves are assumptions from the curious minds ever, Albert Einstein. They are the ripples caused in space-time sheet due to the motion of masses.

Gravitational waves are produced whenever masses accelerate, changing the distortion of space-time fabric. Everything with mass and /or energy can cause ripples. As gravitational waves rolls by it will squeeze and stretch anything in its path but in a very infinitesimally small change which makes it extremely difficult to detect.

So to detect these ripples we use the idea of the time taken by the light to travel is more when the distance increases and less when distance decreases, which is what the principle used in the interferometer. Thus LIGO experiment comes into the picture.

LIGO - Laser Interference Gravitational-wave Observatory.

Here 4km long tunnels are set up where lasers are used to measure the change in distance between the ends of the tunnels.

So when Gravitational wave comes in contact, it elongates space in one direction and squeezes in another direction. By measuring the interference of lasers physicists can precisely conclude about these waves and its incredible as we surely need a smart analysis as it can easily be confused with the other existing waves and disturbances as they are very minuscule.

 Here is the data recorded from LIGO Livingston and LIGO Hanford.

Gravitational waves are helpful in detecting the universe in a whole new way. 
They are significant.


So to know more deeply :
https://physics.aps.org/featured-article-pdf/10.1103/PhysRevLett.116.061102






“The important thing is not to stop questioning. Curiosity has its own reason for existence. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvellous structure of reality. It is enough if one tries merely to comprehend a little of this mystery each day."

How is Schrodinger's cat dead and alive?

SCHRODINGER'S CAT is a thought experiment by Erwin Schrodinger to make the world understand that quantum particles exist in a superposition.

Quantum theory states that quantum particles can achieve more than one state simultaneously.

SCHRODINGER'S CAT EXPERIMENT:

If we put a cat in a strong box with a radioactive sample which has 50 per cent of chances of decaying and closes the box, it is very confusing for the observer outside to guess whether the cat is dead or alive after a period of time.   

         

So before opening the box, we can say that the cat is in superposition. That is it's in the state of both dead and alive. But if we open the box and observe we may find the cat in only one state that is the state of dead or alive.



This means that quantum particles exist in different states but when observed takes a single state.
And according to multiverse theory or many worlds theory, the universe achieves all the possible outcomes by splitting itself and making its copies. So from the thought experiment, we can say that the cat is alive and dead in the split universe. 
That means the quantum particles achieve all the possible positions one in each copy of the universe.


For further understanding :
https://www.aps.org/units/maspg/meetings/upload/franson-021815.pdf
https://www3.nd.edu/~jspeaks/courses/2007-8/20229/_HANDOUTS/quantum-mechanics.pdf

Physics tells us observations can't be predicted absolutely. Rather, there's a range of possible observations each with a different probability.