In space, a bird's feather and a ten-yen coin fall at the same speed. In space, the earth may also be falling in space. Being in space might be an error. From one idea that we have been falling in the endless space for 4.6 billion years, we learn again the fact that we are not in the same position in space for a single second. It could be said that we are on a long adventurous journey in a ship called the Earth. I'm unsure if humanity will endure, but I believe our imagination will take us far.