Is it possible to time travel? May be yes or no. Scientists tell three such ways of time travel by which you can also travel in time, which is scientifically absolutely correct; we just need the technology that can make time travel possible for us. This concept of time travel is not an imaginary thing. Science books clearly say that time travel is absolutely possible. Time travel was first mentioned in the year 1895 when H. G. Wells wrote a novel named ‘The Time Machine‘. After this, this word became very popular. Although this novel was completely science fiction, it created a stir in the world of science, and scientists started wondering whether time travel is really possible. After this, scientists kept giving one theory after another related to time travel and kept explaining those methods by which time travel can be possible. In fact, understanding time is a complex task. Everyone can have different definitions of time. Some measure time with a ticking clock, while others see time from the changes taking place in the universe.
Newton and Einstein's Perspective
Sir Isaac Newton saw time as an arrow. After an arrow leaves the bow, it can only go forward and cannot return. Similarly, time also moves in the forward direction like an arrow, in which time is moving from the past through the present towards the future, which scientists also call ‘The Arrow of Time’. In this, as this arrow of time is moving towards the future through the present, the moments of the present are merging into the past, and the moments of the future are getting transformed into the present. Newton also said that this arrow of time is moving towards the future at a fixed speed.
But after that came Albert Einstein, who completely changed the definition of time. Albert Einstein saw time as an illusion. Einstein believed that time is like a river. Just as the flow of water in a river is slow at some places and very fast at other places, similarly in the universe, time is moving slowly at some places and at a fast speed at other places. Albert Einstein also said that the past, present, and future are also illusions in a way, and all three are already present in the universe. Another form of time is change. Time is moving forward. We can only guess it in one way, and that is entropy. There is a term in the second law of thermodynamics called entropy, which means order to disorder. For example, if you drop a glass on the floor, what will happen is that it will break. Now if I ask you to make that glass exactly like before, can you do that? No, you can try to make that glass exactly like before by sticking it with glue, but you cannot make it exactly like before. If we talk about another example, we can only grow old, but we cannot become children even if we want to. This is the disorder, which is called entropy. Ever since the birth of the universe, disorder, i.e., entropy, has been going on in the universe. This is called change, which makes us feel that time is passing by.
Time as 4th Dimension
According to Albert Einstein, time is a fourth dimension. Like in our 3D world, we can go anywhere in these three dimensions, like forward, backward, up, down, right, and left. Similarly, when we go forward or backward in the dimension of time, we travel in the past or future. But right now, for us, the direction of time is moving in the forward direction towards the future. If we make a time machine, then this fourth dimension of time can be controlled. And the time, which is moving only in the forward direction right now, we can control as per our wish with the help of a time machine and can travel through time. Now the question arises: on which principles will our time machine work so that we can travel through time?
Types of Time Travel
This is the story of the year 1905, when Albert Einstein was working as a clerk in a Swiss patent office in Germany. It was evening time, and he was going towards his home. He caught a tram and started moving fast, but Albert Einstein’s eyes were fixed on a clock tower behind him. As the speed of the tram was increasing, it seemed that the needle of the clock on the clock tower was slowing down. Albert Einstein expanded the scope of his thinking and took this imagination to the next level. He imagined what would happen if the tram in which he was sitting moved at the speed of light. This imagination of Albert Einstein changed the science of the coming times. Albert Einstein had discovered something that created a stir in the world of science. Till now, time travel was only a part of tales and stories, but after the discovery of Einstein, people started connecting time travel with reality. The time inside the train stopped, but the speed of time outside the train increased very fast. Einstein believed that as we moved at a fast speed, the speed of time inside the train stopped, but the speed of time outside the train increased very fast. As we go further, the speed of time will slow down for us. Here is how he explains this through a thought experiment:
1. Travelling at a Speed of Light
Suppose you have a spaceship that can move at the speed of light. By the way, let me tell you that nothing can move faster than the speed of light in this universe. The speed of light is the fastest speed in this universe, which is about 3 lakh km per second. So let’s take our imagination further. You bought two identical watches from the market, out of which you kept one watch in your spaceship and left the other watch at your home. You set the date and time on both watches exactly the same. Your spaceship takes off, and you reach 20% of the speed of light, but for you, time is moving the same way as it was moving before. But if there is a third observer who is keeping an eye on the watches of both of you, then he will see the difference in the watches of both of you. The clock in the spaceship will be moving slower than the clock on the earth, meaning time has slowed down for you. As the speed of the spaceship increases, the speed of the clock on Earth will increase, and the speed of the clock in your spaceship will slow down. Finally, when your spaceship reaches almost the speed of light, the third observer will see a huge change. He will see that by the time only five minutes pass in your spaceship, two days will have passed on Earth. And if you keep travelling at this speed for a whole day, then 19 months will pass on Earth in that time. And you know what is interesting? The speed of time will remain normal for you, and the speed of time will remain normal for the people on Earth as well. No one will even know that there has been a change in the speed of time, but the third observer who will be watching both of you will clearly see the difference. If you keep running your spaceship at this speed for a week, then only one week will pass for you, but 11 years will have passed on Earth in that time. If you keep travelling in the spaceship like this for a month, then 48 years will have passed on Earth in that time. And if by chance you travel continuously for 1 year at this speed in your spaceship, then 572 years will have passed on Earth. And if you spend 5 years in the spaceship, then 2860 years will have passed on Earth. When you return to Earth after travelling continuously for five years in the spaceship at almost the speed of light, you will realise how big a leap you have made in time. When you left Earth in the spaceship, you were 25 years old, but now you are only 30 years old, and you have reached 2860 years ahead of your time in the future. Whatever you had left on Earth, everything would have changed in these 2860 years. This is called time dilation. The time travel you have done is a one-way ticket to the future. This means that you can go to the future with this method, but you cannot return. If you go to the future once, you will remain there.
Apart from this, there are other ways of time travel; let’s know about them.
2. Influence of Gravity
As I just told you, Albert Einstein considered time to be like a river. Just as the flow of water in a river is not the same, similarly, the speed of time is not the same everywhere in the universe. And the thing that affects time the most in the universe is gravity. Einstein believed that where the effect of gravity is greater, time moves slowly, and where gravity is less, time passes at a fast speed. If we talk about our solar system, then the speed of time on all the planets in our system will be different. For example, time on the Sun and Jupiter will be passing at a slower speed than on the Earth, but the gravitational force of Jupiter and the Sun is not so much that it can affect time greatly. Therefore, we will not see much difference in the time of the sun and the earth. But in the universe, there are objects millions of times heavier than the Sun that are affecting time to a great extent, such as black holes. Einstein considered black holes to be a natural time machine because the gravitational force of a black hole is so intense that it even bends light 360 degrees. If you spend just one hour near a black hole, then many years will pass on Earth. And when you come back to Earth, you will find yourself in the future. If you remember, this principle is shown in the film Interstellar, in which there were planets Miller, Mann, and Edmunds near a black hole, where 7 years pass on Earth by spending just one hour. While doing time travel through a black hole, we can only go to the future; we cannot return. If seen, both these methods of time travel through a black hole and time travel at the speed of light are scientifically possible, but we have our own limitations, due to which we cannot do time travel in both these ways. Because neither do we have such technology that we can move at the speed of light, nor do we have any black hole near which we can go and do time travel. And even if by chance we get the technology that allows us to travel through both these methods, even then this time travel will take a lot of time. In such methods, we will be completely dependent on time dilation for time travel, and we will only be able to go to the future, not the past. We want to be able to travel in instant time and make a big leap in time in a single moment. But don’t be disappointed, because scientists have also given the theory of instant time travel.
3. Wormholes
Scientists believe that wormholes are shortcuts in the universe that can make us travel millions of kilometers. If you have seen the movie Doctor Strange, then this concept has been used in it. If we create such a wormhole that opens near a black hole, then we can easily time travel by reaching that black hole through that wormhole. Wormholes are not only shortcuts in space, but they are also shortcuts in space-time. This means that through wormholes we can take long jumps not only in space but also in time. Wormholes are portals that also create shortcuts in time. With the help of wormholes, we can do instant time travel in both the past and the future. If we want to see the origin of humans or dinosaurs, then with the help of wormholes we can go to that era and can also return to our time. This concept of wormhole sounds very good, but it also has limitations. Scientists believe that wormholes are created and destroyed every moment, but they are so small that we cannot see them. These wormholes are smaller than an atom, and as soon as the wormhole is created, they are destroyed immediately. In such a situation, if we have to time travel through a wormhole, then we have to enlarge that wormhole so that we can enter it. Also, we have to prevent that wormhole from closing, because if we go to the era of dinosaurs and the wormhole closes before we return, then we will be trapped there. To enlarge the wormhole and keep it open, we will need negative energy. Negative energy will work like anti-gravity in a way. But creating negative energy is the biggest challenge for us. If we can control dark energy, then maybe we can succeed in doing this.
With havin so much content and articles do you ever run into any issues of plagorism or copyright
infringement? My website has a lot of completely unique content I’ve either
written myself or outsourced but it appears a lot of it
is popping it up all over the web without my authorization. Do you know
any methods to help reduce content from being stolen?
I’d definitely appreciate it.
Pingback: Time Travel Paradox - ASTRONOMY ADVENTURE