To my great-grandchildren Would you like to travel to Andromeda? Then you can look around in that other galaxy and investigate what it is like there. Your great-grandparents had spaceships that traveled so slowly that they could not cover the enormous distance in one lifetime. You have much faster ships, but are they...

Einstein’s Special Relativity Theory was brilliant and many know the famous formula E = mc2. However the theory also was criticized. Ehrenfest, Mach and others showed inconsistencies and even Einstein himself formulated his twin paradox: who has become older after return?With help of Minkowsky he solved...

After publication in 1905 of his Special Relativity, Einstein was praised but he also got a lot of criticism. Paul Ehrenfest, Mach and others revealed inconsistencies. Einstein listened to them and made crucial improvements in 1916 so that the famous paradoxes disappeared. It formed the basis for his General...

How many people understand Relativity? Many say they do, but how do they explain the paradoxes of Special Relativity (SR)? Do they know that Einstein changed his mind about his own SR in 1916? They should know that he abandoned the equality of reference frames already in 1916, solving the twin paradox. Then Einstein...

How do you measure? Crucial is which measuring stick or [unit] is used to read the amount or coordinate on your display. Einstein originally didn’t talk about ‘length contraction’ (amount) but about ‘measuring stick contraction’ (unit). Remarkably Einstein’s theories are cast in mathematical formulas using coordinates...