Trying to imagine what the world looks like travelling at relativistic speeds of course has a noble history, vis a vis Swiss trams etc. etc. I get the thing about passing clocks at speed and staying young by going really fast (and slowing down again). I apologise if this perhaps rather obvious thought experiment has been done to death, but what would it be like to travel on a beam of light itself, by definition AT the speed of light ? What might one see ? What will happen to time ? It's this latter point which intrigues. Is time dilation such that the traveller's time frame actually freezes relative to the rest of the universe ? Does time stand still ? Does light exist (from its own perspective) outside of time ? Do all light wave travellers travel instantaneously to the end of time, the universe and “everything”, observing the rest of us slow coaches fizzle out to cold dark dust in an instant ? From a Newbie waiting to be shot down ! - though don't be too harsh – I'm a veteran of Mr Tompkins and can claim at least an “A” level physics and maths.