- #1
Zman
- 96
- 0
Gravitational redshift is given by the following approximate equation;
[tex]
\frac{\lambda}{\lambda_o} = 1 - \frac{GM}{r c^2}
[/tex]
From http://scienceworld.wolfram.com/physics/GravitationalRedshift.html
Where [tex] \lambda [/tex] is the shifted wavelength and [tex] \lambda_o [/tex] is the rest wavelength.
r is the distance from the gravitating body with mass M
The photon is being emitted from the surface of M directly away from the centre of M.
As r is increased and M constant, the redshift is increased as I expected. The photon has to climb further which reduces its energy which is expressed as a larger wavelength or lower frequency.
But with r held constant and M increased, I expected the energy loss of the photon to be increased at r. The photon now travels through a stronger gravitational field and should lose more energy than when traveling through a weak gravitational field.
But the equation above tells me that if r is held constant and M increased, then the gravitational redshift is reduced.
Where am I going wrong?
[tex]
\frac{\lambda}{\lambda_o} = 1 - \frac{GM}{r c^2}
[/tex]
From http://scienceworld.wolfram.com/physics/GravitationalRedshift.html
Where [tex] \lambda [/tex] is the shifted wavelength and [tex] \lambda_o [/tex] is the rest wavelength.
r is the distance from the gravitating body with mass M
The photon is being emitted from the surface of M directly away from the centre of M.
As r is increased and M constant, the redshift is increased as I expected. The photon has to climb further which reduces its energy which is expressed as a larger wavelength or lower frequency.
But with r held constant and M increased, I expected the energy loss of the photon to be increased at r. The photon now travels through a stronger gravitational field and should lose more energy than when traveling through a weak gravitational field.
But the equation above tells me that if r is held constant and M increased, then the gravitational redshift is reduced.
Where am I going wrong?