Xinhua News Agency, Washington, April 20th-After 45 years of brewing and development, the US gravity probe B satellite with a cost of 750 million US dollars was successfully launched from vandenberg air force base, California on the afternoon of the 20th. Its task is to verify Einstein's general theory of relativity with unprecedented accuracy.
General relativity holds that gravity is the curvature of spacetime caused by the existence of mass, and the existence of gravitational field will change the geometric rules of space-time, which is an inseparable four-dimensional whole. Compared with Newton's classical mechanical theory, general relativity represents the revolution of human view of time and space.
"Gravity Detector B" will verify two important predictions of general relativity. These two kinds of predictions are called geodesic effect and inertial system resistance effect respectively.
The theory of relativity has been confirmed.
188 1 year, American experimental physicist A. Michelson made an experiment on the above problems. A. Michelson measures light along the line with high precision.
Velocity value of propagation in the same direction. In order to detect the expected subtle differences, A. Michelson used very accurate experimental equipment, and his experiments were very accurate.
Yes, the speed difference he measured is much smaller than expected. A: Michelson's experiment has been done many times under different conditions. His experiment got unexpected results. In a moving reference object
In the department, the propagation of light is just the opposite of what we speculated earlier. A Michelson found that on the earth, light travels in any direction at a constant speed.
Same, same. In this sense, the spread of light reminds us of the flight of bullets. We used to imagine that on a moving train,
The movement of the bullet has nothing to do with the movement of the train. Compared with a horse-drawn carriage, a bullet moves in any direction at the same speed.
Thus, A. Michelson's experiment proves that contrary to our conjecture, the propagation of light and the principle of relativity of motion are not contradictory, but completely consistent.
Relativity principle of combined motion. In other words, the reasoning we made in the last section "Will the principle of relativity of motion be shaken?" Is completely wrong.
The 0/00th anniversary of Einstein's Theory of Relativity/KLOC-brought five wonderful discoveries.
This simple and beautiful theory contains too many surprising contents. /kloc-for 0/00 years, people have been aware of the infinite mystery of the universe. Until today, there are still many things that we don't understand.
Text/Gan Xinfeng
The research object of relativity is the high-speed moving world and the vast universe beyond our daily experience, which is the main reason why it is difficult for us to understand relativity.
Since the birth of the theory of relativity, the revolution of time and space brought by it has greatly expanded human understanding of the universe. From the theory of relativity, people have discovered the mystery of time travel, the great energy of atomic fission, the origin and end of the universe, black holes and dark energy and other wonderful phenomena. Almost all the mysteries of the universe are hidden in the simple formula of relativity.
Time travel
Time travel may mean that you can correct or change the development of your destiny, or witness great historical events with people in history; Of course, people may also travel in the future, such as going there to learn about the stock market and explore new scientific discoveries. Time travel opens a door for us to go back to the past and step into the future.
It is a big mistake to think that time travel is only the subject of science fiction, because the idea of relativity shows that time travel is possible.
Special relativity proves that high-speed travel will slow down time. Assuming that at some point in the future, people have solved all the technical problems and can build a spaceship flying at sub-light speed, time travel in a sense will become possible. If the spaceship flies from the earth to a distant galaxy at sub-light speed, it will take only a few years to go back and forth (according to the time on the spaceship), but during this time, thousands of years have passed on the earth and everything has changed dramatically. If human civilization still exists, what new look will it be?
General relativity shows that space-time can be curved, not flat. We can cut a wormhole between the earth and the distance of the universe, and then open this hole with some kind of "strange substance" to make it become a hyperspace pipeline that suddenly appears in the universe, allowing us to reach the other side of the distance in an instant. Then when we came back, the strange nature of the wormhole made us much younger.
General relativity determines that enough mass can change and distort space-time. Mathematician Frank Tippler conceived a method of time travel by rolling up time and space. He believes that if there is a huge object in space rotating at half the speed of light, space-time will be twisted and folded back. So in the future, as long as someone makes a huge cylinder, its length is about 10 times the diameter, and then makes the cylinder rotate at the speed of 150000 km/s, it will create a twisted and folded space-time near the center of the cylinder.
In order to use this cylinder as a time machine, the spacecraft must travel to the center of the cylinder and fly along the inner wall of the cylinder: sailing against the rotation direction of the cylinder means driving into the past, and sailing along the rotation direction of the cylinder means driving into the future, so that the spacecraft will go deeper into the past or future every time it turns. When the time traveler arrives at the destination time, he drives the spaceship away from the cylinder. It must be understood that, like all theoretical time machines, it is impossible to reach an earlier time than making a cylinder through past voyages.
Time travel is a wonderful and fascinating topic. For a long time, scientists have put forward one scheme after another, and the possible problems of time travel have also been heatedly discussed. One day, the fascinating light of relativity will shine on us and start real-time travel.