Brianwave asks ?Does gravity effect light?
You will get advice to read Einstein?s work. I am not knowledgeable in Einstein?s work but I have a little understanding of how he explained light was affected by gravity, or possibly not, within this solar system. Newton?s theories are very mechanical wanting to tell us the weight, mass, of all the things and then calculate the probable attraction that an objects mass might have on another object with a mass of its own. There was an exception for light because the consensus was that light has no mass of its own.
It was noted that stars behind the sun could be visible here on earth at times and Einstein theorized that for the light to be seen space must be bent around massive objects and the light was curving around the sun because the space around the sun is ?warped?. You may have seen an example of this when educators place a billiard ball on a net stretched over a ring and the ball makes a depression when it rolls around on the net. This is to be an example of how massive objects warp space. The curve in space depicts the path light would travel to us from behind the sun.
I would like to see a model of the entire solar system with all the warping of hundreds of objects interplay. It would be educational. When objects fall to earth it is difficult to see a curve in real time because they seem to fall straight down depending on their original trajectory upon entering the atmosphere.
All most all calculations regarding planet and satellites are made using Newton?s theories and are still in use every day. He did not have an explanation for the path of the light, and I am not sure the issue ever came up back then, and Einstein?s theory was accepted as valid. I recognize my ignorance in this regard and I am unable to tell you why light can not be bent by gravity because it has no mass but empty space with no mass can be bent and or warped by gravity. Some other member will explain it for you.
Jim Wood