# If light experiences gravitational redshift as said by GR

1. Jun 1, 2004

### touqra

If light experiences gravitational redshift as said by GR, then, where did the difference between the initial and final energy, $$E = \frac {hc}{\lambda}$$ go?

From Hubble expansion, there is also redshift. Where did the energy difference go?

2. Jun 2, 2004

3. Jun 2, 2004

### TeV

where redshift energies go to

In the simplest case (For that ,imagine two equal photons emited in opposite directions from the massive object):In cowering the difference between inital and final gravitational field strenght of the source of the gravity potential.Accompaning mass of the *emitter* before and after changes.Total energy of the system remains conserved of course.

As of from Hubble expansion red shift,and the question: Where did the energy difference go?:I would say nowhere.Only the density of the energy of the Universe should change.No?

cheers

4. Jun 2, 2004

### Matrixman13

I would think that it goes to space itself. (If there is such a thing)

5. Jun 3, 2004