Astronomy enthusiasts come to help solve basic problems.

I recommend you to watch videos and explore the mysteries of the universe. At the same time, I suggest you know something about gravity and the evolution of stars, as well as non-Euclidean geometry, when the sum of the internal angles of a triangle is greater than 180 and less than 180. Non-Euclidean geometry studies surfaces to help you understand the theory of space bending in relativity. There are also popular books on relativity and eleven-dimensional theory, all of which are calculus, which most people can't understand. You can learn a brief history of time and the universe in the shell.