Enrico Fermi
Fermi wrote a paper "On the Origin of Cosmic Radiation" in which he proposed that cosmic rays arose through material being accelerated by magnetic fields in interstellar space, which led to a difference of opinion with Teller. Fermi examined the issues surrounding magnetic fields in the arms of a spiral galaxy. He mused about what is now referred to as the "Fermi paradox": the contradiction between the presumed probability of the existence of extraterrestrial life and the fact that contact has not been made.
Toward the end of his life, Fermi questioned his faith in society at large to make wise choices about nuclear technology. He said:
Existential risk from artificial general intelligence
Nick Bostrom was the first person to suggest that an artificial general intelligence might deliberately exterminate humankind, and invention of artificial general intelligence is the explanation for the Fermi paradox. Bostrom's 2014 book om the artificial general intelligence question stimulated discussion. By 2015, public figures such as physicists Stephen Hawking and Nobel laureate Frank Wilczek, computer scientists Stuart J. Russell and Roman Yampolskiy, In April 2016, "Nature" warned: "Machines and robots that outperform humans across the board could self-improve beyond our control — and their interests might not align with ours."