Update at 7 a.m. ET, Dec. 21: We're Still Here.
Our original post continues:
It is Dec. 20, 2012 — and citizens of Earth are panicking, consumed by the idea that the world will end Friday, something they say was predicted by Mayan astronomers. Of course, most people are not panicking, and Maya expert David Stuart says no one should. The calendar, he says, has plenty of room to go.