Relativity

Most of everyday experiences deal with objects that move at speeds much less than that of light. The early ideas of Newtonian mechanics on space and time was formulated to the motion of such objects, and this formalism works very well at low speeds. Nonetheless, it fails to describe the motion of objects whose speeds approach that of light. For example, we can test the predictions of Newtonian theory by accelerating an electron through a high potential difference of several millions volts to reach a speed approximately of 0.99c (where c is the speed of light in vacuum). According to Newtonian mechanics, if the potential difference is increased by a factor of 4, the speed of the electron should be doubled to 1.98c. However, in reality, the speed of the electron remains less than the speed of light, regardless of the size of the accelerating voltage [1]. Back in 1905, when Einstein was 26 years old, he published the greatest intellectual achievements of all time, which is the special theory of relativity [1]. Einstein wrote: the relativity theory arose from necessity, from serious and deep contradictions in the old theory from which there seemed no escape. The strength of the new theory lies in the consistency and simplicity with which it solves all these difficulties. We recognize that Einstein was working on electromagnetism and high speeds when he developed the theory, since at low speeds the theory reduces to Newtonian mechanics as a limiting situation.