If you know children who are sick with worry about the supposed end of the world in 2012, here's the antidote: a six-page brief by NASA Ames Research Center astrobiologist David Morrison explaining why the whole Mayan calendar scare is a load of nonsense.
The doomsday scenario, in case you hadn't heard, is that a mythical planet called Nibiru will collide with us on December 21, 2012. You can almost hear Morrison sigh as he patiently explains that there is no Nibiru, calendars can't predict the future, and that the whole thing is being fueled by publicity for the film 2012, which comes out next month.
Also, about the asteroid that had an infinitesimal chance of colliding with Earth in 2036? That's not going to happen, either. The odds of a collision with Apophis just went from one-in-45,000 to one-in-250,000, based on a recalculation of the object's orbit.