<s>[INST] Why is light affected by gravity even if it doesn't have mass? [/INST] Light doesn't have mass but still have energy, and according to general relativity, gravity affects anything with energy, therefore gravity still affects the path of light, but not the speed.</s>\ <s>[INST] Can you concisely explain General Relativity? [/INST] General relativity is a theory of gravitation that describes how massive objects distort the fabric of space-time, causing gravity. In other words, it explains how gravity works as a result of the curvature of space-time caused by the presence of mass and energy.</s>