Lately I have been going nuts trying to find a definitive answer to this relatively simple question. Why does light curve around bodies of mass? After a bit of digging I have found 3 answers. 1. Light follows the curve of space-time. 2. The mass of a photon is attracted by gravity of the object. 3. Light is refracted by the change in the density of space-time. ...and of course I have then 3 questions : 1. If light follows a curve spatially does not that imply that curved space-time refers to volumetric space, instead of (or perhaps including) gravitational forces and time dilation? In other words, this answer seems to imply curved Space rather than curved space-time. If this is the case we can move the discussion https://www.physicsforums.com/showthread.php?t=400147". 2. There have been many discussions about the mass of a photon, and it is my understanding that the mass is so small that only under 'relativistic' forces does it come into play (ie Black Holes). However we see curved light paths around the Sun during eclipse. Does the mass of a photon play a greater role in less force scenarios? 3. If indeed the principles of refraction are at play, would not the light be refracted both entering the density field and exiting, and thus the path of light would make a slight 'S' shape?(see diagram 1). Reason : Light passing a body of mass experiences greater and greater density in the gravity/time field, and thus its refraction curve would increase. Until it reaches the 'escape' point where the fields begin to decrease from there on out and thus would begin to refract in the opposite way through them. http://commons.wikimedia.org/wiki/File:Refraction_varies_by_frequency.gif" [Broken].