No, it is not true that no one understands Einstein's theory of relativity. Einstein's theory of relativity, which consists of both the special theory of relativity and the general theory of relativity, has been studied and understood by many physicists and scientists over the years.
The special theory of relativity, published by Einstein in 1905, introduced the concept of space-time and provided a new understanding of how time, space, and motion are interconnected. It introduced the famous equation E=mc², which relates energy (E) and mass (m) through the speed of light (c). The theory has been tested and verified through numerous experiments and observations.
The general theory of relativity, published by Einstein in 1915, extended the special theory of relativity to include the effects of gravity. It describes gravity as the curvature of space-time caused by mass and energy. The general theory of relativity has also been extensively tested and confirmed through various experiments, such as the bending of light around massive objects.
While the theories of relativity can be complex and involve advanced mathematical concepts, many physicists have a deep understanding of their principles and implications. The theories have been applied in various areas, including cosmology, astrophysics, and particle physics, and have led to important discoveries and technological advancements.
However, it is true that the theories of relativity can be challenging to fully comprehend, especially for those without a strong background in physics and mathematics. The concepts of space-time curvature and relativistic effects can be counterintuitive compared to our everyday experiences. Nevertheless, through dedicated study and effort, many scientists and researchers have gained a solid understanding of Einstein's theories and their implications.