Stephen Hawking: How to create a time-traveling travel machine

Time travel is an interesting topic that is the subject of many science fiction films, besides it also makes a lot of gray matter for many aspiring people to create a capable machine. people return to the past and go to the future. So can that be done? Are there any obstacles? Why has it not been achieved so far? How to build a timeless travel machine? Stephen Hawking, the famous British physicist and cosmologist, will help us solve those problems.

1. Download Stephen Hawking's thesis on the universe

Below are Stephen Hawking's arguments broadcast on "Stephen Hawking's Universe" on Discovery Channel.

Stephen Hawking.

All you need is a deep hole, a Large Hadron Collider particle accelerator or a rocket that can fly at extremely fast speeds.

Hello, my name is Stephen Hawking, a physicist, cosmologist and also a dreamy person. Although I have a lot of restrictions on walking and talking through computers due to illness, my mind is the opposite, they are completely free. Freedom to explore the universe, all things and ask big questions like: is time travel possible? Can we open a gate to the past or find a shortcut to the future? Can we use natural laws to control time? Time travel has been considered a heretical science. And I had to avoid talking about it for fear that people would consider me an odd person, but today is different. In fact, I was like those who had built Stonehenge stones, the ones that were blurred by time. If I had a timeless machine, I would " visit " Marilyn Monroe during her heyday, or visit Galileo when he turned his telescope into the sky. But maybe I want to travel to the end of the universe to see how it is. To understand the reality of time travel, we need to " see " time in the way physicists are looking at - looking at the fourth dimension . Don't worry because it's also simple. Anyone who learns through universal knowledge knows that all objects in nature, even humans, exist in three dimensions, namely length, width and height. But there is actually one dimension, it's the length of time .

As we humans can live for 80 years, the Stonehenge stones have existed for thousands of years, and the Solar system will last for billions of years, everything has its own length of time, and space is no exception. Time travel means traveling through this 4th dimension. To clarify this issue, imagine how we drive everyday. Drive in a straight line that you are driving in one direction, turn left or turn right when you have just added a second dimension, driving up a hill or a downhill is the 3rd dimension. 'in 3-dimensional space.So how do we travel beyond time on Earth? How to find the path of the 4th dimension?

As you often see in science fiction films about time travel, the time machine will create a path, a tunnel through the 4th dimension to allow people to walk through it. The idea is not crazy, but the reality may be very different from what you see on movies. Physicists are also thinking about tunnels this time, but they think from a different angle. But can gates lead to the future or the past can exist but still follow the laws of nature? We think the answer is yes. We even gave it a name that is a wormhole (Wormhole). The truth is that these pits exist around us, only they are too small for us to see. The size of the wormhole is extremely small, they only exist in small angles and in gaps, cracks of time and space. You may start to find it difficult to understand, but wait quickly.

The wormhole opens on one end and the other end leads to another place in the universe.

Nothing is completely flat and solid inside. If you look close enough to see everything has tiny holes and filled with wrinkles inside. This is a basic physics principle, and it is also true for the case of time. Even the surface of a pool has tiny waves. So everything in our 3D space has gaps, and you believe me when I say that this is also true for the 4th dimension. Time also has cracks and gaps. like other objects, and these cracks are very small in size.

Now, imagine that we shrink ourselves to the smallest possible ratio, smaller than the atomic particles, we will reach a place called quantum foam. This is where deep holes exist. Here, the tunnels through space and time are continually born, exist and disappear, and then are born again in this quantum world. And they really link between 2 different places at 2 different times. But unfortunately, these real-time tunnels are as small as one thousand / million / billion / trillion centimeters, so small that people can step through; But from here, the concept of time machine using deep holes slowly appears.

Some scientists think that we can " catch " a deep hole, then enlarge it to billions of times, big enough for humans to walk through, or even a spaceship. If there is enough energy and science and technology, perhaps a giant wormhole will be built in space. I am not saying that it could come true, but if it does, this will be an extraordinary device, with a tunnel head opening somewhere near the Earth, and the other end will open in a very far away place or a some distant planet. Theoretically, a space tunnel (or deep hole) can do more than just take it to other planets. Because if both ends of the tunnel lead to the same place but differ in time, then the spacecraft going through it will return to the past very far, and the dinosaurs will have the opportunity to witness the appearance of modern space ships.

The fastest vehicle people have ever built is the Apollo 10 spacecraft with a maximum speed of 25,000 miles per hour. But to be able to travel over time, we need to fly faster than 2,000 times. Now I find it difficult to think about the 4th dimension, deep holes are very complex concepts that make you headache, but don't be discouraged. Because I thought of a little experiment that could prove whether humans can travel through time through deep holes.

I like small examples like this, and champagne too. So I'll combine these two things to check in my example. Imagine I'm going to a party and my guests will be from the future, and I don't tell anyone about this party until the party takes place. I personally wrote invitations, including the coordinates of the party's time and space, and then copied many copies and hoped that one of these copies would last for thousands of years. , to someday in the future, someone will see this invitation and use the time machine to return to the past and . party. Thereby proving that the theory of time travel is real. In the meantime, my guests can come anytime, count down 5, 4, 3, 2, 1 . but no one comes. What a shame!

I had hoped that at least one Miss Universe would attend my dinner. So why does this test fail? One of the famous causes can be mentioned when talking about traveling in the past, that is paradox. These paradoxes are very interesting when it is mentioned, the most famous paradox most often referred to as " grandfather paradox ", but here I have a new and simpler " version " called " mad scientist paradox ". I don't like how the scientists in the film are often described as crazy, but in this case it's true. Imagine a scientist building a deep hole, then using it to return to the past a few minutes earlier. Now that scientist could see himself a few minutes ago, what would happen if he pulled out his gun and shot him dead a few minutes earlier? Now he is dead, so who killed him? It is a paradox, but it doesn't make sense, but such situations are always nightmares for cosmologists.

An illustrated picture of Hawking sitting with past and future guests.From left to right: Albert Einstein, Data and Isaac Newton.

Another example of paradox : In a university, the professor offered a new mathematical formula and explained it to his students. One of the students used the time machine to return to the past, before the professor found the math formula and explained to him the formula he learned at school. The teacher then brought this recipe to school to teach students. So the question is who is the author of that math formula? This is a paradox.

This kind of timeless machine will violate a law that encompasses this whole universe, that is the law of cause and effect . I believe that all things cannot negate themselves, because if so, this whole universe will be in a state of turmoil that nothing can stop. So I think there is always something that will appear to prevent the paradoxes from happening . In other words, there is a reason why the above scientist could not fall into a situation where he could end his life. And in this case, I regret to say that the problem here is the deep holes. I think that such deep holes cannot survive, because of a phenomenon called feedback. If you watch a Rock concert, you will hear a lot of annoying hissing sounds, that is the feedback. When the sound enters the microphone, it will be transmitted inside the power cord, then amplified several times through the amplifier and exited through the speaker. But these sounds are so loud that the sound from the speakers continues to " squeeze " into the microphone and continue to go through the process. Every round like that, the screeching sound grew louder, if it didn't stop, this feedback would destroy the whole sound system. The same process is similar to the deep hole, but instead of the sound being transmitted here, it is radiation . As soon as the deep pits bulge out, natural radiation rays will get into it first and undergo the same process as the sound in the microphone, the feedback makes the radiation beams stronger and stronger, destroying it That deep hole. Because of that, even if the tiny pits really exist, and one day it can swell, it cannot survive long enough to be a time machine. This is why no one comes to my party. Therefore, any form of travel back to the past by deep pits or by other methods is almost impossible, otherwise paradoxes will occur. This is a sad news for dinosaur hunters and historians. But the story has not ended here, you still have another way to travel, that is to the future.

I myself believe in traveling over time, especially traveling into the future. Time passes like the flow of a stream in which we are caught in a restless way. But there is a special thing that the flow of time is like the flow of water, that is, it will flow at different speeds in different places, and this is the key for us to go to the future.

This idea was first thought of by Albert Einstein 100 years ago. He realized that in space, there certainly exist places where the flow of time slows down and there are also places where time will run faster . And Einstein was absolutely right. The evidence for this theory lies in the space right above our head. Most of us know about the Global Positioning System (GPS), a network of satellites that fly around the Earth to help people navigate through satellites.

But these satellites also show one more thing: the time in the universe runs faster than the time on Earth. Each of the spacecraft launched into space has an extremely accurate clock, though it is still faster than the clock below Earth 3 / 1,000,000,000 seconds per day. And the system always has to adjust to this extremely small change, otherwise the tiny deviation will cause trouble for the entire system, such as making misleading GPS devices on Earth. 6 miles per day (over 9.6 km), a number is not small at all. A fast clock is also easy to see in this case. The higher the clock, the faster the clock runs. The explanation for this special effect is due to the mass of our Earth.Einstein realized that the heavier the object was, the more it " dragged " time to slow down. This will lead us to the ability to travel to the future.

Right in the middle of the Milky Way galaxy, 26,000 light-years away, the heaviest object in the galaxy, it is a superheavy black hole contained within it, a mass equal to 4 million compressed Sun. into a single point by its own weight. The closer to this black hole the stronger the gravitational force. Just getting close enough that even the light cannot escape and is sucked into that black hole. A black hole of this type has a great effect on the timeline, it can drag time to slow down more than any object in the universe can do. And thanks to that, it became a very natural . natural time machine.

I was excited to think about how to make a airship take advantage of this phenomenon by flying around it to go to the future. For the driver at the center below the Earth, they would see the spacecraft take 16 minutes to fly around this black hole, but for the brave astronauts sitting inside the spacecraft near the black hole , time will slow down. And the effect they experienced was even more harsh than Earth's gravity, and the crew's time would be reduced by half. For every 16 minutes of flying around, they really only spent 8 minutes.

Inside the accelerator Large Hadron Collider particle.

And if they continued to fly around like that and " live " half the time of the Earth, it was obvious that they were together with the spaceship traveling through time. Imagine they fly around the black hole for their 5 years, then elsewhere, the time has passed for 10 years. When returning to Earth, everyone was 10 years old, while they were only five years older. So that super-heavy black hole is a time machine, but it's not very practical. Although this type of black hole has many advantages over deep pits because it does not create paradox and is not destroyed by feedback phenomenon, but it is very dangerous, lies far away from us and cannot be bring people to the distant future. Fortunately, we still have a way to go to the future, this is the last hope and the best way to build a real time machine. That is you have to run (or move) at a fast speed, extremely fast. Faster than the speed needed to not get sucked into the black hole. This is because of another strange fact in the universe, that no object can reach the speed of light, also known as the speed limit (nearly 300,000 km / sec).

This is one of the best principles in science. And whether you believe it or not, moving near the speed of light will take you to the future. To explain this, imagine a new transport system like a high-speed train, with rails placed around the Earth. And we will use this super high-speed train to reach the speed as close to the speed of light as possible and see how it becomes a timeless motorbike. On the train were the passengers holding a one-way ticket to the future without being able to return, the train began to accelerate, running faster and faster, soon after it finished running around the Earth and kept on keep running around like that. To achieve the speed of light, the train must run fast enough to be able to run around the Earth 7 times per second. But because even though the train has so much energy, it cannot achieve the desired speed because the laws of Physics prevent it.

Instead, assume that the train only achieves speed close to the speed of light (think so because you can't achieve that speed), right now, other things often catch The beginning occurred. The time on the train will slow down compared to the rest of the world, the effect is the same as when you are near the black hole, but here the effect is more obvious, everything on the train will take place at a slow speed like You play a movie slowly. So why does everything even people on trains are " slowed down "? This phenomenon occurs to protect the speed limit. Because if not " slow projection ", suppose the train is running at nearly the speed of light, then there is a girl standing from the stern and running fast to the top of the train, at this time the speed of She was added to the train's running speed, it turned out that she was breaking the speed limit in that universe. Natural laws don't allow that, so everything will be . " slowed down ". Because they are " slowed down " like that, they are traveling in the future, in other words.

Imagine that the train left on January 1, 2050, it circled the Earth continuously for 100 years before having to stop temporarily on the new year of the year 2150. At this time, the passengers on the ship were only Spending only a week of time due to slowing down time (the effect is much stronger than flying around a black hole). Stepping out of the train, people will see a world far different from what they saw before stepping on the train. In just 1 week, they traveled for 100 years. Of course, currently we can't make a train that can run that fast, but in return the man who built something similar is the world's largest particle accelerator in Geneva, Switzerland. Deep down in the underground, inside the pipes that circle more than 25 km are the millions of billions of tiny particles moving. When powered on, these particles will accelerate from 0 to more than 96,000 km / h in less than 1 second. As the power source increases, the particles continue to accelerate, moving faster and faster. And at some point, they will be fast enough to fly around 11,000 loops per second, which is close to the speed of light. Like the high-speed train mentioned above, they could not reach the speed of light but at the same time could only achieve 99.9% of the speed limit. And at that time, it was these particles who were also traveling through time. We determine this because some particles have extremely short life cycles, called pi-meson particles, which are normally decayed after only 25 billionths of a second, but when they are achieving near-limit velocity, they have survived 30 times longer than usual.

So it is clear, if you want to travel over time, you just need to move at a very fast speed . And what people have done like that is fly into space. The fastest means of transport the species ever built was the Apollo 10 spacecraft, which achieved a speed of 40,000 km / h. But to travel over time you will need a vehicle to fly faster than Apollo 10 . 2,000 times. It will be a giant spacecraft, big enough to carry enough fuel to operate as well as accelerate to near the speed limit.

And to achieve the desired speed, the spacecraft will have to operate at full capacity for 6 consecutive years. At first, the spacecraft will slow down due to its massive size, but then the speed will increase gradually and the spacecraft will quickly reach larger distances. In the first week, it will reach other planets in the universe, after two years it will reach half the speed of light and will be far away from the solar system. For the next 2 years, the speed is now 90% of the speed of light and 30 trillion miles from Earth. And after 4 years of flying in the universe like that, the spaceship will start traveling over time. At this time, every 1 hour on the spacecraft, compared to on Earth, 2 hours had passed, similar to the situation of flying around super heavy black holes. In the next 2 years, at this time the spacecraft's speed has reached 99% of the desired number and every hour on the spacecraft will be equivalent to 1 year on Earth. The spacecraft actually flew into the future. In addition, slowing down time has another benefit, in theory, that allows us to travel to very far away places with just one life. A journey to the end of the bank takes only 80 years.

Overall, the most miraculous thing about this journey is that it helps reveal to us that this universe is strange, it is a universe where the flow of time passes with different frequencies in those Different places, where deep holes exist right around us . And finally, we can apply the knowledge of Physics to become timeless astronauts through the 4th dimension.