Monday, June 12, 2006

REAL Magic Part 2: GPS

This is sort of a culmination of two other topics that I consider to be "magical": space exploration and mathematics. I'll go into each of those individually, but for now, let's focus on this amazing technology that, when explained, seems more fanciful than just saying it's magic.

When I'm doing school assembly programs that promote reading or teach science, I often use magic tricks to illustrate a point or to capture audience attention. Every now and then a child will call out what they imagine to be a plausible solution. My favorites are when they attribute me with powers far beyond anything magical. If I make something vanish, they won't even suggest it is up my sleeve (which it isn't anyway) but instead might yell out "All you did was push a button and the table made it turn invisible!"

As ridiculous as it seems, the real workings of GPS (Global Positioning System) seem equally impossible and ludicrous. The truth is there are satellites circling the globe and constantly sending time signals out. These signals are received by handheld units on the surface of the Earth and based on how long it took the signal to travel through space, the unit can calculate (down to less than a meter) where you are on the surface of the Earth.

That's pretty tightly calibrated time keeping equipment. I mean, how long does it take a signal to travel a meter or two? Imagine a clock that can measure it and then triangulate your position.

That's amazing. Almost like…magic.

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