French astronomer arago once said, "If we don't see objects falling all the time, gravity will be a very strange phenomenon for us."

Astronomer Carl Sagan once said, "Everyone is a scientist when he is young, because every child, like a scientist, is full of curiosity and awe of the wonders of nature."

Zhang Heng, a great astronomer in the Han Dynasty, once said, "Life is diligent, what is there without seeking?"

Astronomer Zhang Heng once said: "Don't respect the position, but respect the morality. Don't be ashamed of Lu's uncooperative and uninformed. "