This paper deals with a subject that dates to the beginning of quantum mechanics, has no formed consensus, splits physicists and philosophers, and is still rapidly evolving. Thus, it is impossible to credit all theories and authors. For instance, although we focused on the Diósi-Penrose model, it is not the only objective collapse theory and not even the only proposal to modify quantum mechanics to incorporate gravity. No field in physics invokes as many passionate philosophical debates as quantum mechanics.