My cousin Henry is answering science questions over at the New York Times. But for heavens’ sake, don’t restrict yourself to questions about science – Henry knows everything and will be happy to tell you so. And if by some miracle you manage to stump him his son Walker, who really does know everything, will answer for him. So go for it – how long should grits simmer? If God is omnipotent, can he make a rock so big he can’t move it? What if Superman had fought for the Nazis? Henry’s ready for all comers.