What is the truth of gravitation? How to solve the problem of gravity quantization? This book introduces a new gravitation theory. Lorentz Symmetry and gravitation are derived results of quantum mechanics actually. We extend the concept of the particle wave into 5-dimensional space-time. The 4-dimensional space-time is only a projection of the 5-dimensional space-time. Particles have a new property named speed symmetry. The Lorentz symmetry is just a projection of the speed symmetry. The rest mass of particles breaks the Lorentz symmetry. This Lorentz symmetry breaking effect is just the gravitation force. But it is not changing the light speed. Gravitation is not a real force. Space-time is flat, not curved. There not exists black hole, but have empty hole. Under weak gravity, new gravitation is equivalent to the General Relativity. But even under weak gravity, if orbit has higher eccentricity, there exists obvious difference between the two theories. So we can test the new theory within the solar system. This book contains many new ideas. It suits all the readers with knowledge of university physics.

XiaoLin Li. A independent researcher in physics. Chongqing, China.