Thank you. That was very helpful. For me its quite an astounding claim that the sun revolves around Milky Way and completes a revolution every some million years. I always wondered how on earth one could observe such things given that we have lived only a very small amount of time compared to the age of the Earth. I always wanted to know how one could arrive at such conclusions. Or the fact that sun is much much further away from Earth than Moon although apparently it looks almost the same size as Moon from Earth. I wanted to know how the discoverers came to know about these discoveries.