If you listen to NASA, there's no need to worry: the Mayan Apocalypse isn't going to happen today as kind of scheduled.
Like clockwork, though, the winter solstice has arrived, Dec. 21 and 22, that is, when the sun appears at noon at its lowest altitude above the horizon.
Broken down, that's the time the Earth's North Pole is tipped farthest from the sun.
Broken down even more: It's the shortest day of the year.
As this calculator on sunrise and sunset shows, daylight in eastern Pennsylvania today shrinks to nine hours, 16 minutes and two seconds.
Sunrise is at 7:22 a.m. and sunset at 4:38 p.m.