I know what it's like to see one's mother go through the agony of death and be unable to help; there is no consolation. We all have to bear such heavy burdens, for they are unalterably linked to life.
Albert EinsteinEither CS (coordinate system) could be used with equal justification. The two sentences: the sun is at rest and the earth moves, or the sun moves and the earth is at rest, would simply mean two different conventions concerning two different CS
Albert Einstein