When the chroniclers of a new Chinese dynasty set about describing the decline of the previous dynasty, they always cite warning portents. The beginning of the end of the Han dynasty, we are told, was signaled by a mysterious green serpent appearing in the Great Hall of Benign Virtue, causing the Emperor to flee in terror. Then an earthquake struck the capital, and tidal waves swept coastal dwellers out to sea. Strange double rainbows were observed, and hens were transformed into roosters. Say what? I sometimes wonder if we are being afflicted with similar omens. I haven’t seen any reports of hens turning into roosters, but this week did turn up a human embryo with one Dad and two Moms, created in a lab in the North of England. Then, on Wednesday night, a mysterious huge fireball lit up the sky over the Midwest. What can it mean? What can it all mean?