Thursday, September 4, 2008

Flying on a Plane and the Theory of Relativity

Being a commuter, I spend a lot of time on buses and trains, and while traveling back and forth from Seattle recently, I realized that the captive time makes my mind race. Well at one point, I had to go to the bathroom, and while standing in line, I got to thinking about the theory of relativity.

Most people know who “discovered” the theory of relativity. But few can explain it. I'm quite sure I would have asked Einstein "what does that mean" when he made the absolute statements about relativity, and I'm sure he would have answered and explained with examples and details. As a digression, Erin will tell you that the statement I make most when I give someone the opportunity to explain absolute statements* is “what does that mean?” or “please give me an example.” It’s a simple statement that you can follow up anyone’s prior statement, and it’s most useful when someone flat out says something you either don’t agree with, want to challenge the validity or conviction of their belief, or just probe to make sure they even know what they are talking about. You’d be surprised how many people try to tell you how you should think. It’s on you to challenge them and ask them “ok, I hear you, but what does that mean??” I find the statement indispensable, and there are lots of other folks eligible for this question. Erin and I always laugh at some of the responses we hear when we ask that simple question.

So what does the theory of relativity mean? Well, relativity was born out of Einstein’s constant struggle to reconcile the speed of light and the measurement of time. I remember the first time I ever read about the theory in Physics in undergrad, and two things stick out: If nothing else, the theory of relativity is profound and should make your head spin, and you realize how far ahead of his time Einstein was as an intellectual. Think of relativity this way, as I am sitting next to Erin on the plane, she and I are not moving relative to one another. However, we are in a plane that is moving at a cruising speed of 450 mph at 30,000 feet. Again, my speed relative to the plane is zero, I am sitting still. But, relative to the ground, I am moving 450 m.p.h. That’s awesome, and guess what?? If I froze the plane in the air, then relative to the plane, the ground is moving 450 miles per hour. Think about that.

Here’s where it gets crazy. If you hold speed constant, the farther away from the ground you get, time begins to slow down. There is nothing that you and I know of that moves fast enough to make this difference noticeable. But if you could move at or near the speed of light, time starts to standstill. It’s a hard thing to conceptualize, but it’s the fundamental basis for time travel, and was instrumental in reconciling the 4th dimension, which is space-time. If you think this is from a science fiction movie, guess again. Global Positioning Satellite units that you can buy for your car sometimes make the marketing claim that they correct for this time lag given that the satellites are moving much faster relative to your position so that you don't have errors in your position magnified...Einstein was ridiculous…think about it. There were no computers back then, just great minds.

*For example, if someone makes an absolute statement like "I think my coworker talks about me?" you should ask simply "What does that mean?" If you can make the person give you an example, or further clarify, 9 times out of 10, if the statement is true, the person can explain what they meant and there is usually a good basis for their belief. If they can't explain their statement or back up with evidence, well, then you know the person just says things with little evidence to back up their beliefs.