Energy Change Due to Doppler Shift

[deadscientist]

Hello all, so let's suppose a photon is being gravitationally red or blue shifted changing its frequency which ultimately changes its energy, where does this energy change come from?

 

[Drakkith]

I believe it's from the potential energy of the system. (Photon + object attracting it)
The photon gains energy and the system loses an equal amount of potential energy or vice versa.

 

[Vanadium 50]

Suppose a drop a ball in a gravitational field and it gains kinetic energy. Where does this energy change come from?

 

[deadscientist]

Thankyou all, answers were very helpful