In NPQG, photons can lose energy as they travel through spacetime æther that is expanding locally in each galaxy. This reaction is one of several causes of photon redshift.

What do we know?

- Energy is conserved.
- Photon energy transfer is quantized.
- We know that certain light generating events emit photons of a particular wavelength which translates into a specific energy.
- We know that as photons pass through expanding spacetime æther their wavelength is elongated and frequency decreased.
- We know the wavelength of the detected photon.
- We know that these photons have lost energy along their journey.

What don’t we know?

- What is the exact mechanism of the energy transfer between photons and the expanding spacetime æther?
- Does the reaction vary with the energy gradient of the spacetime æther?
- Does the reaction vary with the energy of the photon?
- What happens at the extremes of hot and cold spacetime æther?
- What happens at the extremes of high and low energy photons.

I imagine some sort of function that describes photon energy loss per unit distance traveled as a function of photon energy and spacetime æther energy.

Extremely High Energy Spacetime(near or in a neutron star or black hole) local speed of light = slow | Mid Energy Spacetime(near a planet or star) | Low Energy Spacetime(in space far from celestial objects) local speed of light = standard c | |

High Energy Photon | This photon has a small radius, but the spacetime æther particles are dense here. These photons would experience significant refraction. | Refraction | Galaxy local expansion |

Mid Energy Photon | These photons would experience significant refraction. | Moderate refraction. | Galaxy local expansion |

Low Energy Photon | These photons may experience such high refraction that their path is redirected to impact with the dense object or to decay. | Low refraction? Is there a lower bound where the photon decays? | Galaxy local expansion. Is there a lower bound where the photon decays? |

A detailed scientific understanding of the reaction between photons and spacetime æther is required to determine absolute distance in space as a function of photon redshift.

**J Mark Morris : San Diego : California : November 11, 2019 : v1**