Saturday, December 30, 2006

 

Relativity and the Nature of God

Let me preface this essay by posing a question about God, the answer to which has enormous ramifications about the divine nature.

Consider the following scenario: suppose that at a particular instant in time, your sister is halfway around the world, and about to get hit by a truck. Coincidentally, at nearly that precise moment, you offer a prayer, asking God to protect your sister. The moment you offer the prayer is so close in time to the accident, that there is no way *you* could possibly rescue your sister were you alerted to her peril, even if you were able to travel as fast as the speed of light. But what about God? Can God protect your sister as a result of your prayer? Or is He, too, limited by the speed of light?

The ramifications of that question are surprisingly immense. Allow me to jump to the end result: if you believe, as I do, that God is *not* limited by the speed of light, that He could protect your sister even if your prayer is issued only a nanosecond before she gets hit by the truck, then the physics principle of relativity proves that God is not limited by causality--that is, God can produce an effect that precedes the cause.

Let me explain why that happens. Bear with me, this is a little long—but hopefully all in fairly simple language and concepts. All of the following basically stems from the physics principle that there is no such thing as simultaneity. That is, two events which are simultaneous to one observer are not in general simultaneous to another observer.

This is a direct consequence of Einstein’s Second Postulate of Relativity, which says that all light rays travel at the same speed relative to observers, regardless of the motion of the observers. That is a bizarre concept, and foreign to our everyday experience—for example, if you are skating along a road at 5 mph, and throw a ball ahead of you at 5 mph, then a person standing nearby will measure the ball going at 10 mph. And if you throw the ball backwards at 5 mph, then to the person on the ground the ball will appear to just drop straight down. But Einstein says that if you are flying in your rocketship at 100,000 miles per second, and send a beam of light ahead of you at 186,000 miles per second, then the “bystander” will see the light beam travel at 186,000 mps, not 286,000 mps. That is, *you* see the light beam traveling 186,000 mps faster than you, but the *bystander* sees the light beam only traveling 86,000 mps faster than you.

Bizarre! But Einsteinian Relativity has been proven correct countless times since it was proposed in 1905. It is, as far as we know, 100% correct. It affects measureable quantities in very real ways.

To prove that the constancy of the speed of light means that there is no true simultaneity, consider this “Gedankenexperiment” (thought experiment): Frank is standing in the middle of a train car. This train is going tremendously fast relative to the ground, close to the speed of light. Frank is holding two flashlights, and turns them both on at the same time. The light beams travel out from Frank at 186,000 mps, and in Frank’s point of view, strike the opposite walls of the train car at precisely the same time. The impacts are simultaneous.

Meanwhile, George is standing on the ground watching the train go by. However, consider what George sees: George, too, sees both light rays travel out from Frank at 186,000 mps. What he *doesn’t* see, is the forward-moving ray travel faster than the backward-moving ray, which is what would happen if for example Frank were throwing balls on a slow-moving train—in that case, the velocity of the balls would be added/subtract from the velocity of the train like in the skateboard example above. No, instead, George sees the forward-moving light ray travel at 186,000 mps forwards, and the backward-moving light ray travel at 186,000 mps backwards.

As the forward-moving ray travels forward, the front of the train car moves ahead of it. As the backward-moving ray travels backwards, the back of the train car catches up to it. To George, then, the backward-moving ray has a shorter distance to travel than the forward-moving ray, and it hits *first*. To George’s point of view, the two light rays do *not* hit at the same time; the impacts are *not simultaneous*!

This is not only true for “light ray impacts”, but is a general feature of relativity—two things which seem to occur at the same time for one observer will only seem to occur at the same time for people who are moving at the same relative speed. That is, everyone else on the train will agree with Frank that the events were simultaneous, but nobody else will (unless they are on other trains/rockets/whatever going the same speed and direction as Frank).

And actually, even though George thinks the backward-moving light ray hits first, other people won’t even agree on *that*. For example, if Herman is on a second train, traveling even faster than Frank’s train, he will think that the other light ray hits first.

Moreover, it is impossible to say whether Frank, George, or Herman is “right”. They are in fact *all* correct—none of them has what you might consider a “privileged viewpoint”. In fact, that is essentially Einstein’s First Postulate—that there is no such thing as a privileged viewpoint. All (non-accelerating) points of view are equally valid.

How does this relate to the prayer for your sister?

Well, although *you* might think that your prayer was issued a split second *before* she was miraculously rescued from being hit by the truck, to someone speeding past the earth in a rocket, your prayer was issued a split second *after* the miracle occurs. And even though such a person might not actually exist, the point of view, or “frame of reference” as physicists call it, is a valid one. One cannot say that the prayer was issued before the miracle, if there is *any* valid frame of reference in which the miracle came first.

When the equations for determining times and locations of events in different frames of reference are used (the “Lorentz transformations”), it turns out that as long as two things happen close enough together in time that a light-ray (or anything slower) couldn’t go from one to the other, one can *always* find some frame of reference where event 2 precedes event 1.

So, as I said in the introduction, if you do not think that God is limited by the speed of light, then physics tells you that God can produce a result *before* the cause. And that, in my opinion, is just plain cool. It tells me that God is not bound by time in anywhere close to the same sense that you and I are.

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