Gravitational redshift is given by the following approximate equation;(adsbygoogle = window.adsbygoogle || []).push({});

[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 travelling 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?

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Gravitational redshift equation

Loading...

Similar Threads - Gravitational redshift equation | Date |
---|---|

I Gravitational redshift | Dec 26, 2016 |

A Gravitational Redshift in Newtonian Equivalence Principle? | Oct 1, 2016 |

Why doesn't the vertical light beam get out of a black hole? | Oct 14, 2015 |

Deriving the gravitational red shift? | Jan 18, 2015 |

Gravitational red- or rather blue-shift when approaching Schwarzschild radius | Nov 16, 2014 |

**Physics Forums - The Fusion of Science and Community**