Here's a quick story that explains the chosen topic : We were at physic class explaining the lesson of mechanical waves, when the teacher said that sound doesn't propagate through vaccum. I suddenly turned to my twin sister and told her : "i think that's why human can't hear anything in Space". When i arrived home, i searched about it and found that it was true, so i wanted to talk about sound in Space. Hopefully, i got this chance to speak loud about it !