I just have one question:
If we travel with light i.e. we ride along a beam of light,according to einstien then, we must measure it at 300000 km/s,but that would indicate that another observer who is at rest wrt the the sun, stars, earth etc. should calculate the speed of light as 600000 km/s. But then that goes against what einstien had stated. So I just want to get this cleared, what prevents this from happening