The answer on my question Does light accelerate as it nears a black hole? leads me to think that light 'gains' the gravitational energy by shifting to a frequency with a higher energy (blue). Is this thought correct?

And is there any method of forcing light to red-shift?

Is this the same principal where low temperature combustion is red... Higher temperature blue (stars)?


You can reflect it on a moving mirror... which will cost you exactly the amount of energy that you will gain from the blueshift. Sorry... no free lunch.

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  • $\begingroup$ If by using a moving mirror to redshift light, in what form would the energy released after the shift? $\endgroup$ – darkspine Mar 3 '16 at 16:46
  • $\begingroup$ The energy gets transferred to (or from) the kinetic energy of the mirror. A real application of this could be solar sails for spacecraft. $\endgroup$ – CuriousOne Mar 3 '16 at 20:51

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