And the condition of transcending time and space is to let time to go back. However, Einstein also suggested that the speed of an object should not exceed the speed of light.
However, according to scientists' research, when the spacecraft passes through the gravity field, the tension of the gravity field is converted into thrust. During that time, the spacecraft can fly at the speed of light or even superluminal. Experts from NASA established the theory of spatio-temporal vibration, which is based on the unified field theory of Einstein and German physicist Heisenberg. Its essence is that with the help of the elasticity of the co-evolution of electromagnetism, gravity, light speed and space-time, it can instantly cross the interstellar space of stars. At that time, time reversal will no longer be an unsolved mystery.
Of course, it's all theory.
■ In September 2003, the popular science magazine Newton Science World reported the manufacturing method of the time machine proposed by Australian physicist paul davis with the title "When will the time machine start?".
■ On April 20th, 2004, NASA launched a scientific satellite "Gravity Exploration -B", which took 45 years to develop. It wants to verify with unprecedented accuracy whether the space-time distortion predicted by Einstein's general theory of relativity really exists.
■ People don't know whether "Gravity Detection -B" will add another cornerstone to Einstein's theory, or will shake and fundamentally change our understanding of the universe and time and space; Paul davis and countless sci-fi fans are equally eager for its answer: Is time travel possible?
When people begin to observe the universe scientifically, I believe that most people's dreams of traveling in space will also be shattered, because astronomers tell us that the universe is so big that we can hardly imagine it!
The Milky Way, where we live, seems to be a huge whirlpool surging with rapids. Countless stars gather here because of gravity. There are about 200 billion sun-like stars in the Milky Way, and according to the current observation of human beings, the number of galaxies in the universe is about 50 billion to 654.38+000 billion, which really amazes human beings.
Expert Jiang said that our current space capacity is like being in a big city. We just walked out of a house and walked around the house. Such a circle is really too small for the whole city. If you want to travel in the universe in the future, it is impossible to rely on the current space means, even the space means we can imagine today. It is a fact that you have to travel through time and space. Experts believe that time-space travel needs to change the structure of time and space, because according to the traditional idea of acceleration, even if the existing spacecraft accelerates to near the speed of light, it is impossible to travel in the universe. For example, the nearest galaxy to the Milky Way is Andromeda, which can be seen by naked eyes in a clear night sky. Andromeda galaxy, also known as the straw hat galaxy, looks like a beautiful Spanish straw hat. However, even if we travel at the speed of light, it will take us 2.3 million years to reach that straw hat.
From 65438 to 0997, the sci-fi movie Contact with the Future, which was adapted from the sci-fi works of the famous American astrophysicist carl sagan, was put on the screen.
Sagan wants to tell a story about human contact with aliens, but he can't imagine how humans can contact aliens. Later books had to be dealt with in this way, so that more advanced alien civilizations could teach the earth people how to make a time machine by radio, which could establish a convenient passage between the earth and Alpha Lyra. In the movie, the heroine boarded a spaceship with a rotating mechanical arm at her feet, as if she had entered the turbine of a giant centrifuge. In the film, people saw the heroine riding a time machine and quickly entering a colorful tunnel. Finally, she came to Alpha Lyra.
Alpha Lyra is a Vega that China people are very familiar with.
It takes 26 years to travel from the earth to Vega at the speed of light. Jiang said that a round trip to Lyra described in the movie only takes 1 second on earth, which is a means of using time to travel.
□ 100 years ago, Einstein put forward the famous special theory of relativity. According to the special theory of relativity, some surprising inferences can be made. For example, if a person can travel near the speed of light, time will stagnate for him.
Since ancient Greece or even earlier, people have had many thoughts about time, but the real connection between time and space and a theory of time and space began with Einstein 1905' s special theory of relativity. He first put forward a concept that time and space are not independent of each other. For example, with the change of human motion state, time and space may change in different reference frames, which may not have been thought of before. This theory actually provides scientific support for people to change the simple view that time and space will never change.
Young Einstein likes to observe the light and shadow in the Woods best. In the special theory of relativity, the core is that the speed of light is constant. It believes that no matter how fast the light source moves or in which direction the observer moves, the speed of light will never change. All movements, even time itself, must correspond to it, so Einstein first proposed that time is relative.
197 1 year, physicists Richard Keating and Joey Haffler put four extremely accurate atomic clocks on an ordinary sailboat. After the flight, these atomic clocks were found to be 59 nanoseconds slower than those placed on the ground. It not only proves that the special theory of relativity is completely correct, but also shows that it is theoretically feasible for people to live longer by flying, but the effect is too weak.
But in the particle accelerator, the time expansion effect predicted by special relativity is not so weak. In the 40-kilometer particle accelerator in the United States, subatomic particles can accelerate to more than 90% of the speed of light when passing through this giant device. At this speed, the time changes obviously. According to the calculation of special relativity, the mass of flying particles increases, while under normal circumstances, the existence time of short-lived particles increases greatly. This proves that time slows down for these particles.
For time travel, the most important influence after the emergence of general relativity is to provide a wormhole theory, which can make you go back to the past. According to Hawking's description of the wormhole, it is a slender space-time pipeline that communicates between the universes.
19 15 years, Einstein's more profound general theory of relativity came out. General relativity relates gravity, space and time, and predicts that gravity will bend space-time, just like a bowling ball on a piece of paper, and the mass of a star will distort the surrounding space-time.
19 19 years, people observed the change of starlight during the solar eclipse and found that the gravity of the sun would indeed bend the light of the star.
For time travel, the most important influence after the emergence of general relativity is to provide a wormhole theory, which can make you go back to the past. According to Hawking's description of the wormhole in A Brief History of Time, it is a slender space-time pipeline used to communicate information between the universes. Although the wormhole is vividly depicted, it is actually just a mathematical model. Various ideas about it can be regarded as different solutions to Einstein's gravitational field equation. 1935, Einstein and Rosen deduced the channel according to the field equation in their paper, which is called Einstein-Rosen bridge. In this paper, the bridge is impassable. When the spaceship tries to cross the bridge, it will break. But in 1949, the Austrian mathematician Gaarder found through calculation that in fact, in some cases, the bridge will not be broken, and the general theory of relativity made people go back to the past, which also surprised Einstein.
Jiang said that since time and space have been proved to be possible in theory, people will continue to explore along this theoretical line. The more serious problem is that if we can travel back through time and space, then we may break the law of causality. The earliest example conceived by physicists is the so-called grandmother paradox, which says that if you go back in time and meet your grandmother, you accidentally kill her, so that you can't be born. Of course, if it's not born, it's gone. Since you don't exist, how can you kill your grandmother? This constitutes a paradox.
□ Parallel Universe According to Hawking's explanation, after the time traveler went back to the past and changed history, the time line bifurcated, and the bifurcated time line started another period of history, while grandma still existed in another period of history.
Jiang said that the theory of parallel universe was originally put forward to solve the problem of going back to the past, interfering with history and destroying causality. But now people can also find some weak support from some physics.
Quantum theory is a set of ideas used by modern physicists to study the microscopic atomic world. Its core idea is that nature is discontinuous at the microscopic level, which is completely contrary to Newton's classical mechanical theory. 1in March, 994, David deutsch of Oxford University published a paper "Quantum Physics of Time Travel" in Scientific American magazine, expounding the physical possibility of time travel, which he thought was a "multi-world" theory based on quantum mechanics. In the subatomic world, quantum uncertainty is dominant. An electron collides with a proton, either to the left or to the right. This uncertainty is likely to cause the multiplicity of the universe. According to the "multi-world" theory, the universe has infinite parallel worlds from the beginning.
It seems that with the concept of parallel universe, the problem of time travel changing history can be solved harmoniously, so now we can see that in more and more movies describing time travel, the view of parallel universe is frequently used to repair logical contradictions. With the concept of parallel universe, the time machine can move forward boldly.
Jiang believes that wormholes are the most convenient means of time and space travel that everyone can imagine now. Theoretically, there may be some wormholes in the universe, but we haven't found a way to find them yet. There is no way to find them. There are some wormholes in the universe that are only theoretical. If we use wormholes properly, it is possible for us to travel in time and space. It is possible for us to travel between different parallel universes. Another way is to imagine making a wormhole artificially, and physicists have imagined this problem. These assumptions blur the line between science and fantasy. In fact, it is a mixture of scientific fantasy and pure theoretical discussion of physics. Building an artificial wormhole is a pure imagination in the theory of physicists, and there is no technical means to achieve it at present.
Time travel may be realized in the next generation, or it may always be just a dream.
Wells wrote at the end of The Time Machine: People have no choice but to marvel.