The speed of Light is frequency times wavelength.

Will let ν = frequency

Will let λ = wavelength

Where c = νλ

Where plank's constant is h

Where photon energy = νh

Gravitational potential energy is given as GMm/r

And a photon mass is νh/c

We will write it as νh/c^2

It is not a rest mass.

So the potential energy of a photon to leave a gravitational well GM(νh/c^2)/r

So the photon will after leaving the gravitational well have the energy of ν'h

Where νh - GM(νh/c^2)/r = ν'h

And the new wavelength λ'

Where λ' = c / ν'

I may have left out some steps. But they can be inserted were needed.

Will let ν = frequency

Will let λ = wavelength

Where c = νλ

Where plank's constant is h

Where photon energy = νh

Gravitational potential energy is given as GMm/r

And a photon mass is νh/c

^{2}We will write it as νh/c^2

It is not a rest mass.

So the potential energy of a photon to leave a gravitational well GM(νh/c^2)/r

So the photon will after leaving the gravitational well have the energy of ν'h

Where νh - GM(νh/c^2)/r = ν'h

And the new wavelength λ'

Where λ' = c / ν'

I may have left out some steps. But they can be inserted were needed.

## Comment