# reflection at speed of light when both mirror and viewer is travelling at the speed of light [duplicate]

consider me sitting on the top of a train which is travelling close to the speed of light, will I be able to see my image on a mirror which I'm holding in my hand??

## marked as duplicate by Alfred Centauri, Waffle's Crazy Peanut, Brandon Enright, user10851, twistor59Jun 11 '13 at 16:14

• If an object moves with speed $c$ in one frame of reference, it moves with speed $c$ in all frames of reference, i.e., there is no frame of reference for objects moving with speed $c$, no frame in which the object is at rest. This is one reason it is generally pointless to ask question of the form "will I be able to [whatever] if I'm moving at the speed of light?". Such questions presume that one can move with speed $c$ and have a frame of reference but that's a contradiction. – Alfred Centauri Jun 11 '13 at 14:05
• The linked question referenced as duplicate is gone. Is there another link that is a duplicate question? – Kyle - Microsoft Oct 17 '17 at 22:03
• Voting to reopen since the duplicate-source is deleted... – Tobias Kienzler yesterday
• Probably would be better to just request the other question be undeleted than reopen this one, @TobiasKienzler – Kyle Kanos yesterday
• @KyleKanos How so? I don't know why the other one even got deleted nor can I check its quality (lacking 10k rep). But either way I'm fine – Tobias Kienzler 1 hour ago

• "torn apart"? I do not believe this is generally true; in your little spaceship, you'd still claim that all the laws of physics are the same, and that you are indeed happily at rest (or accelerating at the same rate as you were before you reached $0.9(6)c$). In other words, your speed has nothing to do with the forces you experience. – Rody Oldenhuis Jun 11 '13 at 14:51
• @RodyOldenhuis Maybe I was exaggerating a bit. But forces are involved - in order to reach (almost) $c$ at a constant acceleration of, say $5g$ (which is what test subjects could bear for some 10 minutes), you'd have to accelerate for about 70 days (in your own inertial frame, externally it's about 27% longer). And since at $5g$ you'll probably have trouble eating&stuff you cannot accelerate permanently. Unless you increase the acceleration significantly (which would tear you apart), the tension (=suspense) would kill you... – Tobias Kienzler Jun 12 '13 at 6:45