Time travel is always been a very fascinating subject. It simply means travel in past or future. Who doesn’t want to travel in our past or future? Everybody wants. But is it ever possible to travel in the past or in the future? Does scientist has already achieved success in it? You may have watched lots of movies related to time travel. check out best ten time travel movies. We are going to know about travelling in time and its possibilities with a paradox which can arise during it.
The topic we are going to discuss here:
- Understanding the Time
- What is Time Travel? and History of Time Travel
- Possibilities in Time Travel
- Time Travel Paradox
- Frequently Asked Questions
Understanding the Time
Before we start to discuss the time travel, we should know what exactly the time is? Many people think that time is a constant physical unit. It is the way to measure the period between two points of incident.
But physicist Albert Einstein has shown time from a different perspective. He has joined term time with space and deliver a different theory on time. Before Einstein, time is just a measurement unit, but in Einstein special theory of relativity, he has shown that time is relative.
Time is relative to a different person in a different area of space. Time is relative for people who are at a different speed. Einstein showed that time and space are co-related to each other.
According to Einstein, space and time are in the form of fabric, where sun, moon and other planets lie. Space and time is the fabric which can be stretch, bend and rotate. He believes that time is the fourth dimension. From this theory, there arise different theories who support of time travel. We will discuss them later.
What is Time Travel? and History of Time Travel
Time travel is the movement between two points of time, either past or in future traditionally with the help of a hypothetical machine called time-machine. The concept of it has been using in many sci-fi books, films and dramas since long. The very first time, the concept of the time machine was popularized by the novelist H.G Wells in the year 1895 through his novel Time Machine.
There are lots of stories of ancient times, where time travel has been performed by many people. In Hindu mythology, there are some stories related to it. one of those is the story of Mahabharat where a king Raivata Kakudmi travels to heaven to meet the creator god Brahma, but when he returned many years has passed away. Similarly, in Buddhism, there is a story which told about the relativity. It told that the time in heaven moves differently from time on the earth. There are lots of ancient theories about it.
The concept of travelling in time was very famous among the fictional writes. Early sci-fi stories featured the characters who went to sleep and wake up in different time period and also transport in different time period through supernatural powers. Some of the stories are Rip van Winkle (1819) by Washington Irving, Looking Backward (1888) of Edward Bellamy and When the Sleeper Awakes (1899) by H.G. Wells. The concept of prolonged sleep and time machine has been used in these stories for its.
Possibilities in Time Travel:
Time travel is still a mystery. There are not any proven and practical ways for it but there are lots of possibilities of it depended on different theories in physics. So, here we are going to discuss some of the ways which can be used in it.
Wormholes are like a tunnel in the space-time which connects two parts of the universe. They form because of the curvature in space-time due to the heavily weigh celestial bodies. Wormholes are the shortcuts in space-time to travel a long distance in a short time. Since time and space are interlinked with each other. Theoretically, if you enter from one side of the wormholes, then you can escape from another side in a new time period. This is how we can travel in time through wormholes.
2. Black hole:
Black holes are the heavily dense and high gravitational celestial object. It has so much gravitational power that it can observe all the light. We know that time is relative. We also know that time goes slow in near heavyweight bodies like a black hole. So, if we travel near to the black hole time goes slow for us but here in earth time has its usual period. With this phenomenon, we can easily travel in future with the help of a black hole. But this process is irreversible.
3. Travelling near speed of light:
Just like a black hole, if we travel near to the speed of light, time goes slower for us. Time is relative to speed. So, if we travel near to the speed of time, it goes slow for us but time remains the same on the earth. For example, if we travel one year in speed near to light then it will be thousand of the year on earth. That means we have travelled in the future. This is also the irreversible process.
4. Tipler Cylinder:
Tipler cylinder or Tipler time machine is a hypothetical object, which is used in time travel. The Tipler cylinder is discovered as the solution of the equation of general relativity by William Jacob van Stockum in 1936 and Komel Lanczos in 1924. But it was first analyzed by frank Tipler in 1974 and showed his idea about Tipler cylinder.
According to his theory, an infinitely long cylinder is rotated at its longitudinal axis through which frame-dragging effect creates. With this process, it opposes a closed timelike curve and spacecraft can go backwards in time. but this can only be done in the presence of negative energy. This is only a hypothetical concept which cannot perform practically in the current situation. But physicist Stephen Hawking believes that it can be performed partially when the finite cylinder is rotated in the infinite speed. If ever the tippler cylinder becomes reality then it could be another way for time travel.
Time travel in today’s world seems totally unrealistic but in future, we don’t know what will happens. Although our science and technology have achieved a lot in physics quantum computers (learn more about quantum computer here.) and information technology but still, our technologies and science are not so advance to prove that it is actually possible but lots of theories and equations give us hope that one day we will able to travel in time.
Time Travel Paradox:
Travelling in time is very fascinating. But there are some paradoxes arise when the concept of time travel comes in an action. We are going to discuss one of the famous paradoxes here on it. Paradox simply means a contradiction in any theory and subject.
Grandfather paradox was introduced in written stories in the 1920s. This paradox makes a contradiction on time travel. According to this paradox, when a man travels in past and killed his grandfather, then he also erases the possibilities of his own birth. It shows that if a man is unable to born then how he travels in past and killed his own grandfather. This has made some of the scientists to believe that time travel is not possible in past.
But many also believe that time travel in past is possible but no one can change the past. There is also another possibility which is that a man cannot travel in his own past but travel in his past’s copy, where he killed his grandfather and come back to his original world. This is the phenomenon arise from parallel universe theory.
Similarly, if we look into this paradox in the quantum world, we know that everything is in superposition. If a man travels in past and killed his own grandfather, then there were two possibilities whether grandfather died or not. So, from this concept two possibilities arise parallelly in the same world. The concept is also shown in the thought experiment of Schwarzenegger cat experiment.
In conclusion, in this blog, we have learnt about time and time travel. We have discussed four ways of travel in time. They are black holes, wormholes, speed of light and Tipler cylinder. We also discussed the grandfather paradox which opposes the general concept of travelling in time and how scientists counter this paradox. Overall, it is a hypothetical concept which may be or may not be true in future.
Frequently Asked Questions about time travel
According to the special theory of relativity, time dilation means slower in time when we observe time in relative to two different frames. The equation that Einstein shows for time dilation is:
Δt = the observer time, or two-position time (s)
Δt0 = the proper time, or one-position time (s)
v = velocity (m/s)
c = speed of light (3.0 x 108 m/s)
A time machine is a hypothetical machine used in time travel. Nobody has ever made a time machine till now. Our physics and technology is still not that much advance to make any time machine.
Nobody knows whether time travel will possible or not. Currently, our researches and experiments don’t give any signal of possibility of it but in future maybe we can get access to the technology which allow us to travel in time. For now, it is just a hypothetical phenomenon.
Many theories claim that wormholes actually exist in this universe, but practically we haven’t discovered any wormholes in the universe yet.
Yes, black holes are actually exits in the universe and scientists have found the evidence of black holes and in year 2019 scientists have published the first image of black hole. That was the black hole located in Messier 87 galaxy, in the Virgo galaxy cluster, which is 55 millions light year away from Earth.