Light/emf only existing/propagating in mediums. All matters in space are connected by universal gravitation force and universal repulsion force, gravity is the attraction force between masses, and levity is the repulsion force between the surfaces of masses. therefore light and gravity are instantaneous in space. Forces are coexisting with matters, forces have no speed, internal property of the mass.

2 electrons at any distance repel each other with force F=Ke x ee/r^2, fact. electrons are on the surfaces of all matters, fact. Therefore universal repulsion force /levity in space is fact.

It is important to realize that in physics today, we have no knowledge of what energy is. We do not have a picture that energy comes in little blobs of a definite amount. It is not that way. -Feynman

All these fifty years of conscious brooding have brought me no nearer to the answer to the question, “What are light quanta?” Nowadays every Tom, Dick, and Harry thinks he knows it, but he is mistaken. - Einstein

Redshift is BS. There is impossible anything waving in space without the existence of matter/medium. Only matters can wave/motion. Every star has different mass, therefore different accumulated energy and temperature, and ocsillate at different frequency range. Small stars look redder, large stars look bluer. Simple fact. Light does not travel in space, light induces light throughout space simultaneously by universal repulsion force F=Ke x q1q2/R^2. q1 and q2 are the total line of sight electric charge on the surfaces of mass 1 and mass 2.