Two drugs that may aid kids with muscular dystrophy; demise of the dinosaurs; profile of Franklin Chang-Diaz; northern lights.

Two drugs that may help kids with muscular dystrophy or the frail elderly, who don't have the option of hopping on a treadmill to build strength and endurance; renowned paleontologist George Poinar, who has announced his discovery of multiple clues to parasitic pandemics that could have been just as instrumental in wiping out the dinosaurs as the hypothesized asteroid impact; a profile of rocket scientist and astronaut Franklin Chang-Diaz; and the beauty - and dangers - of the northern lights.