Space cannon was a superweapon. It didn't belong to this era. If one were to put a time stamp on it, it was a weapon of one or two millennia later.
Humans of this age didn't have the ability to build such weapons. However, Himmel Soan, the 200-year-old man, had successfully built one. Because of the space cannon, people began to believe his age.
Maybe he was the key to saving Earth!
The original plan was to spend two hours on the space cannon and one hour on the underground shelter.
However, the audience was so intrigued that they kept bombarding Himmel Soan with questions. After three hours, they were still inquiring about the space cannon.
Himmel Soan cleared his throat, saying, "I think we should stop here. I've told you the space cannon's overall structure and principle, and you've seen the diagram. Let's move on to the next subject. I'm going to tell you why I find the arks unreliable and why we have to build underground shelters!"