Dense phosphorus area
So I think that the reason why we are the only planet out there that has life is that we are in a area in the universe that has just enough phosphorus which is one of six essential chemical elements required for life and we somehow had enough phosphorus and the other 5 elements to create life and that is why these other planets that we have observed that are so close to how earth is do not have life only because there is not enough phosphorus in that part of space. Let me know what you think.