What if our universe was not the only one? For several decades now, the hypothesis that the universe we live in is only one among an infinity of others has come a long way. The plausibility of this idea is growing among theoretical physicists, it coincides with the promotion of multiple worlds, multiverses, allowing us to understand quantum physics. Worlds where the properties of elementary particles and their interactions with each other would be different from those proposed by our universe. The fundamental principles of nature would then no longer be absolute. Not so strange, since history has demonstrated on several occasions that understanding our universe is not limited to the "visible".