★★★★ Yes, this is a pretty cool show, if not especially uplifting tonight. Because the learned discussions, involving the brainy and geeky Dr Karl Kruszelnicki and Adam Spencer, is about the ways in which the world could end. And, indeed, may end. Any time soon. Or not, as the case may be. How will it end? A nuclear explosion, perhaps? A volcano? A huge asteroid? Sorry, that would be telling . . .