we all know abt twin paradox(except those poor souls who would rather read playboy than physics today!) now a very fundamental question abt it is; does time realy gets slow when we r moving with speed comparable to that of light or its just 'malefunctioning'(mark the word) of clocks? what i mean is that, our most realiable source of measuring time is light itself! consider a clock witch consists of a stick an a light source, we measure time by using lenth and velocity relation. now when we move this clock to a rather high velocity refrence frmae, length of stick changes , speed of light remains same, so we got defrent time rate. does this really have to do with real time? i mean time we can measure by biologicl processes like aging. i dont know abt it, do u? it may be that when twin come back from his journey he will find himself as agd as his brother, just his rolex is some years behind!