Hi, I got interested in physics last night and there are a few philosophical questions that came into my mind. I have no formal education in this field but nonetheless, maybe you can answer in a simplistic manner. 1. Particles that has mass affect spacetime and are also affected by spacetime. Particles that don't have mass, like photons do not affect spacetime but are affected by him. Are there particles that affect spacetime but are not affected by spacetime? 2. What is energy? (please no answers like the ability to perform work of something that fills in equations) is it movement? Is there an energy field? Please feel free to tell me the above is nonsense if it is so.