The world has always been furious to know if we can travel back to time and change things like telling my father which stock to invest in so that we end up becoming a very rich family in the present. But have you ever thought about the time travel possibility seriously? One can have a series of questions and an infinite long debate on the topic ending up with ” Who Knows?’’!
2500 years ago, In the Hindu mythological Veda The Mahabharata – Time Travel is mentioned and in the same way found by Albert Einstein. The theory that says that Time and Space are relative to each other was already talked about by the Hindu god Brahma during the Satya Yuga ( 115 million years ago). The story says that there was a King of the solar dynasty Kakudam who had a beautiful daughter named Revati. She reached her marriage age and was not getting a perfect husband match for her. Kakudami went to the plane where God Brahma – the creator resides. He was watching a musical performance so Kakudami waited but when they met Brahma after 20 minutes, He laughed and told them that while he waited 20 minutes for him, He actually lost 108 years on Earth as Time passes differently in both places.
Another mention of Time Travel has been given in the old classical Japanese story of Urashima Taro where a man goes into the sea and visits the God of Sea for 3 days, around 300 years have passed away on land. These legends show that mankind has always been curious and familiar with the concept of Time Travel. But still, they know nothing about Time.
In classical physics, Time was considered as an entity that moves only forwards and space was treated as a container but with the entry of Einstein, Time and Space were joined by a thread that is unbreakable. Albert Einstein told us that to define an object’s position, one has to tell the time and space associated with it. For example, When you tell your friend to meet in a cafe – you always have to inform him When to do that! similarly, if you tell your friend that you will meet him at 4 o’clock You also need to inform him Where!
Einstein gave the world the theory that changed the world which is called ‘The theory of general relativity’. It states that gravity is related to time. How? Well, the more gravity you feel- the more time slows down for you. This is the basic reason why you need Black Holes for time travel. When you go near a black hole, you feel such a powerful gravity that time nearly stops for you. The US National Institute of Standards and Technology already tested it in 2010. They placed two atomic clocks on a shelf – one on top of the other. They noticed there was a difference in ticking between the two.
Can you Really Travel Time and go to the Past or the Future?
Coming back to the actual question , I would say yes and no at the same time. What I would rather say is Time Travel to the future is definitely possible but it is impossible to go to the past. Now you may have a lot of questions as to why I said that? Actually I would also like to add that time travel to the future is possible only theoretically and not practically. Why is it so?
So first of all, The idea to travel to the future is widely accepted by scientists all over the world because of Albert Einstein’s theory of relativity. The theory told us about Time slowing down at a place where there is a lot of gravity or when you are approaching the speed of light. There are many ways to do that.
How To Travel To The Future?
You can actually travel to the future if you can make the below-mentioned things possible. These things are only a theoretical concept and not practically tested as we lack the scientific advancements required to make them possible. Maybe a few years from now, these conditions can be achieved.
Approaching The Speed Of Light
If one is able to create a spaceship that can travel as fast as the speed of light, He/she can actually travel through time and reach hundreds or a thousand years later. A Proton travels at the speed of light and it has been found through experiments that 1 second for a proton is 11 months for us which means 1 minute traveling at the speed of light will jump us through 55 years later on Earth. Using this piece of calculation, we also get the mind-bending information that spending 1 whole hour at the speed of light will land us 3300 years later on Earth. Of course, If you make it – you are not going to see your friends or John Cena at that time.
Experiencing The Strongest Of Gravity
Another thing needed for Time Travel is a strong version of the gravity that we currently experience – strong enough near a black hole entrance. If one can reach the event horizon and spend some seconds there, he will be losing hundreds or thousands of years on Earth. Notice that I am always using the word “Earth” because time travel changes that you will see because Earth’s time is different. You are actually not going into the future but you are just waiting for The Earth to grow old. In this case, your waiting time is just a few seconds.
Some creative questioning geeks among you all would also like to know that when you are going to reach the event horizon of the nearest Black Hole which is 3000 years far away from us, much time would have already passed as compared to the time dilation experienced in the horizon. So, you don’t need to reach the horizon- you just need to travel to the place.
This idea has been supported by one of the great physicists Stephen Hawking who says Wormholes are basically shortcuts in spacetime which connects two different places in time. At a quantum level, wormholes are just smaller than the atom but capable of bridging the gap between billions of light-years in the universe. If somehow, humans find a way to create a wormhole big enough for a human on earth that will require a tremendous amount of energy.
Why Does Time Travel To The Past Seem Impossible?
Traveling to the future is possible theoretically but to the past is impossible as confirmed by today’s scientists. Why? What is wrong in traveling to the past if it is possible to go to the future? Hold on, I am here to talk about this topic very briefly. Some paragraphs ago, I told you that when we were going to the future – we were not actually going to the future but just by using the advantage of us being in a place where time slows down, we were waiting for the time to pass away on Earth. We can not term it as actual time travel but how the hell are we going to travel to the past then? Is there a way that we can actually wait in the reverse order so that time moves in the backward direction? The answer is simply no.
There are a number of things that don’t fit in EVEN if we were able to make it to the past and in the next few paragraphs, I am going to elaborate on them. So get ready to think differently and question things!
The Grandfather Paradox
Let’s start with an example. Imagine that you make a time machine and are able to go back in time as well as go forward. You choose to go to the past to see your grandfather’s childhood. When you were meeting him, because of you, there was an accident and the old man died. Now your grandfather never grew up and then never married a girl so your father was not born resulting in you never being born.
The question arises if you were never born – THEN who are you? What is your identity? And If you were never born then obviously there was no one to build a time machine who will go to the past to kill the grandfather which means that your grandfather never died in childhood so everything goes okay and BRR You are born again. I know it is difficult to digest what I just told you which is apparently termed as “ The Grandfather Paradox “ in time learning. Paradoxes are like the glitches in science. The only possible solution to The Grandfather Paradox is that we cannot go to the past and change things simultaneously. Or there is a possible explanation to this paradox which says that when you went to the past and killed your grandfather – that event created an alternate timeline like a multiverse in comics. The events in that timeline don’t affect your original timeline and you still exist in your timeline whereas in that alternate timeline – You were never Born. The idea of a multiverse seems far more uninteresting and messing up at the same time that scientists prefer not to talk about.
Now that I have mentioned a paradox here which is a topic that I am always excited about I will also like to mention one more paradox here which is called “ The Predestination Paradox ’’ or “ The Causal Loop ’’ or “ The Bootstrap Paradox ’’. Let me explain this to you in a very human-understandable way.
The Bootstrap Paradox
Suppose, In a way you wake up on your bed and there is a knock on your door. You go to the door and open it. You see no one outside. Then you look on the floor and find that there is a diary with a cover on it which says “ The Time Traveler ’’. When you read the diary, you find out that there is no name to it and it has a brilliant story and also a map of a machine at the end of it. Years pass by, you published the diary under your own name which became a bestseller. Meanwhile you were also working on the map to make that machine which turned into a time-traveling machine. Now, you understand the story. You go to the past and find yourself and put the diary in front of your younger self’s house door. When he opens the door – he finds the diary and the cycle goes on and on and on forever. But your brain starts to sweat thinking “ Where the hell is the beginning of all this!’’ which simply means WHO ACTUALLY WROTE THE DIARY?
The origin of the diary is what makes it a paradox and is called a causal loop. This is a never-ending time loop where an object or a piece of information is sent back in time where it influences the happenings in such a way that In future, that information or the object again goes back in time to do the same thing again.
The Fermi Paradox
The term was coined by Italian-American physicist Enrico Fermi who questioned that If there are extraterrestrial civilizations out there then why haven’t we encountered them in our history. It simply seeks the answers to why aliens never chose earth to invade.“ The Fermi Paradox’’ says that if time travelers exist, Then why haven’t we seen any actual person claiming to have come from the future? Which really makes sense at once. This paradox says even if we find a way to time travel in the upcoming years- we still would never find a way to go to the past. I think there might be travelers living among us but Who KNOWS? They might be hiding so as to not make any wrong happenings in the future.
The Butterfly Effect
There is even a Butterfly effect that I would like to mention which was introduced by Edward Lorenz in the late 1960s. The Butterfly Effect was never introduced in any relation to time travel but scientists started realizing it’s importance in the subject. The Butterfly Effect simply means that even a small change in the course of events can alter a big cause in the happenings. It was found that an incident as small as a butterfly flapping its wings in Chicago can result in a tornado occurring in Tokyo. Suppose, for an example if you go to the past at the exact place where Newton was supposed to discover gravity. You are watching him closely but an insect or more precisely a honey bee sits on your hand. You give your hand a jerk and the honey bee goes away. This little honey bee then goes towards Newton sitting under a tree who is about to see an apple falling from the tree. Newton’s focus shifts towards the honey bee and the apple falls but he couldn’t notice it. This little incident works like a butterfly effect resulting in Newton never discovering gravity.
The Newcomb’s Paradox
William Newcomb devised a thought experiment which indirectly later proved that a time machine or a time traveler should not exist in our world because if they exist- they might be knowing the future and if they know the future, then they have information about the future describing to what decisions are going to be taken and what will be the result of them. This will contradict the principle of free will ( free choice ) and determinism which means that everything we do in the present has already occurred in the future and thus whatever we do, we will eventually be doing what the traveler saw in the future and if it happens it will contradict the existence of the time machine or traveler in the first place.
So eventually we find that time travel to the past can create a lot of mess than to solve it. You might have heard about Pauli’s Exclusion principle. It says no quantum data with the same properties can exist in the same system (This is just a simple definition I made up for you, you can look upon the Internet for more clarity). So If you travel to the past and meet your younger self, that is definitely not according to the principle. Both of you shouldn’t exist simultaneously.
These paradoxes are the questions that lead us to the impossibility of time travel to the past but no one actually knows what’s waiting for us in the upcoming year? Still, I will say, at the time of writing this article, that time travel to the future also seems impossible unless you shrink to the size of a photon and ride through a million years in the future. There are ongoing experiments on quantum particles being accelerated to match the speed of light but we don’t know for sure how many years or hundreds of years it’s going to take before humans can travel at that much speed. Anyway, I am going to grab my coffee and my two days of sleep which I missed while writing this article! Thank you for reading it and I hope you will share this piece of knowledge to anyone you think might be interested. Till then, I will be figuring out my next topic. Bye!