Wikimedia by user Bukvoed, used under Creative Commons CC0 License.
The type of radar used by NORAD to track Santa rotates
steadily, sweeping the sky with a narrow beam searching
Every year NORAD brings up their official Santa tracking radar. You can track Santa’s location for yourself at www.noradsanta.org. In light of the Christmas season, I wanted to share a few facts about Santa’s travels around the globe and the technology behind NORAD.
Santa travels about 56 million miles to reach every home in the world. Not counting the time he is in your house, he would have to travel at 560 miles a second to make his global trek. This is 3000 times faster than the speed of sound, but still 300 times slower than light. This is a good thing for NORAD since they use radio waves that travel at the speed of light to track moving objects. This also means that you might see Santa fly overhead, but you will never hear him coming.
So how does NORAD work? NORAD uses a network of satellites, ground-based radar, airborne radar, and gather jets to detect, intercept, and if necessary, engage any threat to Canada and the United States. Lucky for Santa, he is too fast to intercept. The fastest man-made vehicle is the Ulysses space probe which is not even able to achieve top speeds (only 27.4 miles per second) in the earth’s atmosphere, more than ten times slower than Santa’s sleigh.
NORAD tracks Santa because of how the radar systems work. In the simplest of explanations, you can think of a radar station as throwing electrons in the form of light at the sky in a known pattern. If the electron hits something, it bounces straight back to the radar unit. The radar unit knows how long it takes an electron to travel a certain distance and can then determine where the object was when the electron hit it.
The crazy part is they can only track where Santa was and maybe guess where he is going, but not where he is currently. The speed at which he moves means that if he is 3000 miles from the radar unit, it will take 0.01 seconds for the radar to bounce from his sleigh. In that time he will have traveled 10.5 miles. This means that we never know if Santa is in town but we know he was here, because by the time we detect him on radar he is already gone.
So can we tell exactly where Santa is with satellite imagery? Actually, it gets much worse with satellite. Since the satellites orbit at around 22,000 miles above the surface, by the time the satellite sees Santa he has had 0.12 seconds to travel and has cleared a distance of 44 miles. In this case the satellite can tell if he has been in the county, but not until long after he has left.
So kids, let’s just say your chances of catching Santa in person on Christmas night are very poor. You might catch him on a very high-speed camera as a blur, but even with a camera a few feet away, in the fractions of a second it takes the camera to capture the image, he will have moved across the room.