Trax3001BBS (2368736) writes "You know the old question of the photon traveling at close to the speed of light passing near a black hole; how much speed will it acquire from the a gravity assist?
The answer I'm fine with is the photon ejects a gamma wave and maintains it's original speed.
How about the reflection from a mirror moving close to the speed of light. The reflection will pick momentum from the speed of the mirror.
Albert Einstein stating that the reflection from a mirror moving close to the speed of light could in principle result in bright light pulses in the short wavelength range
A team of physicists from the Max-Planck-Institute of Quantum Optics(MPQ) in Garching...created such a mirror in a recent experiment."The scientists used an intense laser pulse to accelerate a dense sheet of electrons from a nanometre-thin foil to close to the speed of light and reflected a counter-propagating laser pulse from this relativistic mirror.instead of moving faster (photons already travel at the speed of light),the reflected light is shifted in its frequency.
In the experiment, the incredibly high velocity of the electron mirror gave rise to a change in frequency upon reflection from the near infrared to the extreme ultraviolet up to a wavelength of 60 to 80 nanometre.
Moreoever (sic), the time duration of the reflected pulses was on the order of a few hundred attoseconds only (one attosecond is a billionth of a billionth of a second).
This experiment not only supports Albert Einstein's theory of special relativity, but attosecond pulses of light would allow the electron motion in atoms to be resolved,"