I'm here to talk about the theory of General Relativity, this involves an ideas called light deflection, which is exactly what it sounds like- the path of a beam of light is not entirely straight.
As strange as this may seem to you, it's been proven repeatedly. What this means is that, even though light doesn't have any mass, its path is affected by things that do-such as the sun. So if a beam of light from, lets say a really far off star in the sky passes aclose enough to the sun it will actually bend slightly around it, The effect on a star gazer such as us is that we see the star in a different spot of the sky than it's actually located (much like fish in a lake are never spotted where they appear to be when looking at them from above water). So remember the next time you look up at stars, it could all just be a track of light.