The concept that photons are massless entities is founded in obsolete information. It has long since been determined that photons do in fact carry mass. When p

The concept that photons are massless entities is founded in obsolete information. It has long since been determined that photons do in fact carry mass. When photons were initially conceptualized, the capacity to estimate their mass was too small to measure and thus prove to experimentalists. Theorists, therefore, focused on other concepts and problems. Taking a look at the link you've provided actually reaffirms this fact. Mote that it is a question from a novice, and the very first answer refutes the idea that photons lack mass. In other words, a photon does have relativistic mass proportional to its momentum. And here we have it: photons have 'mass' inversely proportional to their wavelength! Then simply by Newton's theory of gravity, they have gravitational influence. Keep in mind that the top google results for stack overflow style Q & A forums aren't always going to line up in favor of your search queries. You should read the top answer, since it's more likely to contain reliable facts, and not presume that the ideas expressed by the question are essentially correct.