Hello everyone. I am Sing Lau, a 14-year-old student from Hong Kong. I do astrophotography. At the same time, astronomy theories attract me so much, and raise my infinite number of questions(some stupid). I am here to thank everyone that may answer my questions in the future. Happy Physics! PS: (I don't know if it is appropriate here) Feel free to follow my ig account lunar_site_of_sing_lau. All about astrophotography.