To answer Pascal's philosophical questions concerning our place in the universe and the passionate interest of the public, the field of action of scientists could not be limited to astronomy.
We tend to say that the universe began with the Big Bang and then expanded. It is a metaphor, but everyone understands what it represents or nearly.
The shape of the "world" has always aroused our curiosity. If we believe that the universe is finite, common sense leads us to believe that this universe must be enclosed.
We all know that earth's always rotate from the beginning to present, but what we are going to ask is, how Earth really moves? Did earth just spinning and revolutioning itself to sun?
Deep in the night sky, in the constellation of Sagittarius, shrouded by interstellar gas and dust, lies a mysterious object. So enigmatic is this object, it cannot be observed directly, not even light can escape its presence.