Einstien revealed the inchangeability of mass and energy. SO... doesn't it follow that energy can attract gravitationally just as fully as mass? The entire universe ia suffused with light of various frequencies, more so around galaxies since the billions of stars are continuously emitting new light. Is the density of that energy factored into graviational caculations? If not, isn't a major error being committed?
How much mass is the sun "losing" every day? What percent of that mass is in the form of light? I think these questions have answers. Is the amount of light within the sphere circumferenced by the Earth's orbit a negligible contribution to the total attraction we experience from the sun? Although the density of this "photosphere" is minute, it is -- very roughly speaking -- a million time more volumnious.
Would anyone care to turn these thoughts into calculations?