well you can outrun light in some cases, the speed of light through some mediums is actually slower than other things (no examples come to mind though)...lights speed depends largely on what it's travelling through
light photons are not affected by the density of surrounding space, they get affected by gravity fields of stars and black holes etc. When light passes by an object with large gravity it bends a little, as proved by the 1919 experiment during a solar eclipse which was used to test Einsteins theory of relativity. See link below
http://www.earthmagazine.org/article/ben...relativity