Physics is like this. Archimedes dug a cave to live in. Galileo thought the cave was too crude. He dug a hole to build the house. Newton contractor, with Kepler, Hooke, Descartes and so on a group of little brother laid the foundation. Over the next few hundred years, a group of physicists, including Faraday, built a house that looked beautiful and perfect. Then Kelvin said that the house was finished, everybody went to live, it was perfect, the physicist had nothing to do, but it was not sunny, there were two clouds on his head? As a result, Maxwell made two lightning bolts and the house collapsed. Maxwell said, Genima's house, long vision? "The dark clouds were not actually made by Maxwell, but Maxwell's equations predicted that the speed of light would remain unchanged. As the fourth physicist, he had to do a hegemonic job of demolishing the house." So Einstein, the contractor, appeared. He first led Lorenz and other youngsters to build a floor of "Special Theory of Relativity," and later he did. All the younger brothers did not have to build a whole building upstairs. The building was unfinished, and the scientists behind it, Schwarzschild and Hawking, were decorating it on Einstein. Hawking probably had a wall. At the same time as Einstein, Planck, Bohr, Heisenberg and others, oh, and Einstein, they built another building, that is, quantum mechanics, these people built together, there is no foreman, this building now seems to be more bullish, and Yang Zhenning, in this building, made an elevator shaft, using a standard model. Through the building. So Yang Zhenning and Hawking can judge who is taller and who is lower, one decorated the wall, one hit the elevator shaft, as for Einstein with the building and Newton with the foundation, let alone mention it. Later it was discovered that the two buildings could not be connected, and Witten and his men used strings to bridge the bridge there. At present, it seems that only a rainbow bridge, can not walk, the future is not necessarily, perhaps the rainbow bridge is the truth?