Our General Physics Lab project that day was meant to help us lowly underclassman understand the coefficient of friction. It wasn’t very exciting; we had a ramp we could ratchet up and down, creating different angles, and a bunch of things to place on the ramp. We had already figured out there was no point setting anything on the ramp at a 45 degree angle; even the rubber-backed place mat wouldn’t stay put on a ramp that steep.
Then the door slammed open so hard it smacked into the wall, and a wild-eyed graduate student raced down the corridor between our lab tables. He vaulted onto the teacher’s desk at the front of the room, and grabbed the heavy clock that was set into the wall above.
This was the olden days, when electric clocks were wired to the wall through their backs; he had to yank several times before the clock came loose, trailing electrical wires and chunks of plaster. He held up the clock like Rafiki presenting baby Simba, and yelled at the top of his lungs, “TIME IS RELATIVE!” Then he leapt down from the desk, and ran out of the room, taking the clock with him.
Shocked, we couldn’t stop laughing; when the teacher came to check on us, (he knew the coefficient of friction wasn’t as funny as all that) we told him about the crazed grad student. He grinned and said, “That’s how I felt when I figured it out.”
Two years later, when I understood enough math to grasp the theory of relativity, the student’s crazy behavior finally made sense to me. The world I knew, the world I’d grown up in, wasn’t real. My senses were tracking time, but the time I experienced was an illusion, not an absolute at all. Time is dependent on our speed and acceleration. Time is profoundly affected by gravity. Time can be rotated. Time, in fact, is completely bizarre and weird and behaves in ways I’d never imagined. I found myself in awe of Einstein (but not for the first–or last–time!)
If you use your cell phone’s location feature, your phone is constantly receiving signals from at least four GPS satellites, and you rely on the theory of relativity daily. GPS satellites move over 8000 miles per hour faster than we do, so they experience a slower slow of time. The satellite clocks have to be calibrated to nullify the time difference, or GPS technology would be worthless. Siri (or Google Maps, depending on your preferred tech) couldn’t answer your questions about how to get to the nearest gas station, or tell you how far you were from your destination.
So the next time you ask your phone for directions, remember Albert Einstein deserves some of the credit for getting you where you want to go.