As of today, special relativity is the most accurate model of motion at any speed when gravitational effects are negligible. Time and space cannot be defined separately from each other. In einstein special theory of relativity pdf to include gravity, Einstein formulated general relativity in 1915. How far can one travel from the Earth?
Reflections of this type made it clear to me as long ago as shortly after 1900, i. Gradually I despaired of the possibility of discovering the true laws by means of constructive efforts based on known facts. The longer and the more desperately I tried, the more I came to the conviction that only the discovery of a universal formal principle could lead us to assured results How, then, could such a universal principle be found? The laws by which the states of physical systems undergo change are not affected, whether these changes of state be referred to the one or the other of two systems in uniform translatory motion relative to each other. Following Einstein’s original presentation of special relativity in 1905, many different sets of postulates have been proposed in various alternative derivations.