I'm a music professor and there's a famous story about an infamous American composer, John Cage. He's the one that "wrote" the piece 4'33" (the piece where a pianist comes out on stage, sits down, positions their hands just above the keyboard, and holds them there for 4'33". The "music" is the audience's reaction). Back in the 1960s Cage wanted to know if there was such a thing as complete silence. He went to AT&T's sound lab, which had the best sound room at the time. He discovered that even when there was nothing audible, his ears picked up the sounds of his central nervous system. So the answer to this question is no, there is no such thing as silence.