Courtesy of Jason Verbelli and his TheRealVerbz YouTube channel, details at the bottom of the post.
There are two parts to his outstanding synopsis
The Huygens–Fresnel principle (named after Dutch physicist Christiaan Huygens and French physicist Augustin-Jean Fresnel) is a method of analysis applied to problems of wave propagation both in the far-field limit and in near-field diffraction and also reflection. It states that every point on a wavefront is itself the source of spherical wavelets, and the secondary wavelets emanating from different points mutually interfere.[1] The sum of these spherical wavelets forms the wavefront.
PART 1
A post of mine involving redshift which is relevant to critics of emissions theory is HERE.
Extinction Shift Principle (under the electrodynamics of Galilean Transformations) highly technical PDF download:
It just so happens I have a different idea of what makes a galaxy rotate and one or two other points but its not critical, sharing ideas is.
PART 2
PART 2