If you are in a spaceship that is traveling at the speed of light, and you turn on the headlights, does anything happen?”
h/t Steven Wright
If you were in a spaceship traveling at (just below) the speed of light and turned on the headlights the illuminated scene would look perfectly normal to you. To an outside viewer, however, the headlight’s photons would barely be making it out of the filament (or equivalent spaceship light emitter).