Santa Claus is coming to town. But when, and where is he now?

Everyone knows that Santa will eventually end up on our doorsteps this year, but sometimes the anticipation of exactly when that might occur is too much to bear.

Need to know precisely where Santa is on Christmas Eve? Excited kids all over the world have a number of high-tech options for keeping tabs on jolly old St. Nick this year. For more than 50 years, the North American Aerospace Defense Command (NORAD) has been helping kids track Santa via a hotline (1-877-HI-NORAD) and now also on on its website, on Facebook and on Twitter. Kids with smartphone access can also track Santa via Google Maps or the Santa Tracker app.

The tradition started by accident

So how did this Santa tracking get started? It all started in 1955, when a Sears Roebuck & Co. ad in a Colorado newspaper printed a phone number that kids could call to connect with Santa — only the number was off by a digit and instead directed them to NORAD's emergency hotline. NORAD's director of operations at the time, Col. Harry Shoup, didn't want to disappoint the kids, so he ordered his staff to check the radar and let the kids know where Santa might be. And thus Santa tracking was born.

Since that time, NORAD volunteers have staffed the phones on Christmas Eve to keep kids posted on Santa's whereabouts. First lady Michelle Obama even surprised kids last year by personally answering Santa tracker calls.

How does NORAD know how track Santa? According to the website, NORAD uses four high-tech systems to track Santa: radar, satellites, Santa cams and fighter jets. "Amazingly, Rudolph's bright red nose gives off an infrared signature, which allows our satellites to detect Rudolph and Santa," it says.

Happy tracking!

This story was originally written in 2011 and has been updated with more recent information.