 And how long will that nuclear winter last? You know, it's an interesting question you ask, because when the nuclear winter theory first came out in 1983, and it was led by Carl Sagan and his four fellow authors, one of those was Professor Brian Choon, who's still alive. He was Sagan's young student. I interviewed him at length for the book. And Professor Choon and his new team, they've been working on this issue for decades. They now use state-of-the-art climate modeling systems