The Time Travel Hypothesis

Hello guys !

Well I read your responses on my last post and I was surprised by reading the mind bending thoughts of the public. A few wanted to go back in past, a few wanted to see the future and few to stay and live the present. Today I am going to communicate and tell my thoughts on this topic. Though time travel is a topic on which a book can be written then also I'll try to summarize it as much as I can.  

Time Travel is a concept that for ages has been a dream for the human kind and an aim to achieve for the scientific community. The only two reasons people want to time travel is either to change (or alter) the past or to experience (or discover) their future. Well as interesting this thing sounds its way more complex than that. 

The most important rule to time travel to past is to avoid a temporal paradox (time travelling paradox). There are two types of temporal paradox- Consistency paradox and Casual Loop 

1. A simple and quite famous example of a consistency paradox is the grandfather paradox. Suppose you have the ability to time travel and you decide to go back in time and kill your grandfather which will then avoid the birth of your father which means you were never born and if you were never born, you never went in past and killed you grandfather, and if you never went in past to kill your grandfather this means your grandfather is still alive ! This is a paradox.
2.  A casual loop is a paradox of time travel that occurs when a future event is a cause of a past event, which in turn is the cause of future event. Both events exist in spacetime but their origin cannot be determined as this forms an infinite loop just like the chicken and egg problem. Eg of a casual loop is the predestination paradox. 

  So to explain the temporal paradox different schools of thought are there. 

• Some believe if you are caught in a paradox your existence will be erased from the timeline.
• Few believe that a paradox will give birth to a new universe called "daughter universe" without changing the present timeline.
• Few think that if you time travel in past and change a major event or even a "butterfly effect" then you will rewrite the actual timeline and all your memories from the timeline before you time travelled will be erased, which basically means you will start thinking that this is your life and you will completely forget your past life and even the power of time travel that you got.
• Last (though there are many more) is the explanation done by quantum physics - quantum superposition, quantum entanglement etc which in one way is illustrated in Schrodinger's cat thought experiment. 

Okay its enough about about the time paradox. Now lets get to the main point that how can we time travel? Again as time travel hasn't been discovered there are dissimilar thoughts. Few believe its impossible to time travel others believe it is possible. 

I think time travel is possible and I guess after string theory this will be the next target in science.  

Ways to Time Travel 

(1) To travel in future you need to go very close to a black hole and then return back to Earth. If you manage to come back on Earth (though the odds are less) well then congratulations as you have travelled to the future ! This time travelling mechanism is possible because of the Time Dilation. Its not compulsory to go near a black hole if we get the knowledge to know how to manipulate the gravity, then time travelling to future can be done from any place.  

(2) To travel in future you need go far away from earth with high speed and then come back which is again allowing you to time travel because of the Time Dilation.

(These two are the only working ways to time travel at present to future with a one way ticket.)

(3) We can travel in past or future by wormholes or Einstein Rosen Bridge 

(4) Travelling faster than speed of light as time travels slower the faster you move.

(3,4 points are theoretical as today's technology cannot achieve this. Third and fourth method can happen both the ways.)

Few fun facts about time travel-

(i)  Time passes faster for your face than for your feet (assuming you're standing up). Einstein's theory of relativity dictates that the closer you are to the centre of the Earth, the slower time goes. So it means your feet is younger than your head !

(ii) When the dinosaurs were alive, there were 370 days in a year. The Earth's spin is getting slower because the moon's gravity is acting as a drag, so days are getting longer, by about 1.7 milliseconds per century.

(iii) On Mercury, a day is two years long.       

(iv) There's no such thing as "now" as far as physics is concerned. Space and time are fluid, affected by gravity and your speed. Einstein put it like this

 "For us physicists, the distinction between past, present and future is only a mere illusion, however persistent."   

(v) There are people who claim to time travel like - John Titor, Noah, Jophar Vorin and few more.

The movies that motivated me to write about time travel are - 

• Interstellar
• Back to the future (all parts)
• Star Trek
• Edge of tomorrow
• The time machine  
• (A special mention to avengers endgame also)

Conclusion : Nature is full of secrets if we learn them then we can do things more interesting and unimaginable than time travelling itself.

Key Words

1. Paradox (Oxford definition) - A seemingly absurd or contradictory statement or proposition which when investigated may prove to be well founded or true. Eg, the uncertainty principle leads to all sorts of paradoxes, like the particles being in two places at once.
2. Daughter Universe Theory (space.com) - The theory of quantum mechanics, which reigns over the tiny world of subatomic particles, suggests another way multiple universes might arise. Quantum mechanics describes the world in terms of probabilities, rather than definite outcomes. And the mathematics of this theory might suggest that all possible outcomes of a situation do occur — in their own separate universes. For example, if you reach a crossroads where you can go right or left, the parent universe gives rise to two daughter universes: one in which you go right, and one in which you go left.
3. Butterfly Effect (American Scientist and Wikipedia) - It is a concept invented by the American meteorologist Edward N. Lorenz to highlight the possibility that small causes may have momentous effects. In chaos theory, the butterfly effect is the sensitive dependence on initial conditions in which a small change in one state of a deterministic nonlinear system can result in large differences in a later state. Eg, Flutter of a butterfly in one region on earth may cause a tornado in the other region.
4. Time Dilation - It can be explained by special/general relativity but explaining in the most simple words it means if you manage to come to a place with very high gravity (generally a black hole) or if you can manipulate gravity's power then the gravity will bend time so much that 1 minute for you can be 10 years or 100 years on Earth !
5. Wormholes - They can be understood through Einstein Field Equations but again putting in very easy words, they can be thought as a tunnel or a bridge that link 2 points of spacetime.
6. Spacetime - Its a four dimensional model made when 3 dimensions of space and 1 dimension of time fuse together. 
7. Black Hole (Wikipedia) - A black hole is a region of spacetime where gravity is so strong that nothing—no particles or even electromagnetic radiation can escape from it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. 

 

Question of the week

What would happen if you fall in a black hole?