Monday's Lesson #3

Monday's lesson this week is not to get so wrapped up in building a boat, that you forget it's Monday, and there should be a lesson.

Actually the lesson is a relativistic concept:

"The Word" on the Colbert Report a week ago was "Elsewhere," my favorite word. Not only does it roll smoothly off the tongue, it has a wonderful weird physics meaning.

Colbert was reporting on the closing of Guantanamo Bay Prison, and advocated sending the prisoners elsewhere. Little did he know how very effective that would be.

If terrorists are elsewhere, they cannot effect us. Elsewhere is the term in relativity for any space-time points outside of our lightcone. If the terrorists are outside of our lightcone, then no light signal they send can arrive at our space-time point. Even more, no airplane can fly into us, no anthrax-laden mail can arrive in our mailbox, nothing else, travelling slower than light, can arrive at our space-time point and affect us. Placing terrorists elsewhere effectively keeps them from affecting us.

But before you get comfortable, remember that if they are elsewhere, we cannot keep an eye on them. We can't know what they are doing right now, because a light signal from them, showing us what they are doing, cannot reach us at our current space-time point.

Also remember that we do not stay in one space-time point. Even if we don't move in space, we definitely move in time (scientists have yet to figure out how to avoid that). The terrorists may be outside our lightcone now, and what they do now cannot affect us now, but it may be able to affect us in the future, after the light signal, plane, or envelope has had time to move through space to wherever we are, or will be.

Can we put them somewhere where they won't be in our light cone, for say, 100 yrs? Yes, but it would take us more than 100 yrs to get them there, since they can travel away from us only at speeds less than the speed of light that defines the cone. Can we cut down that time, if we also travel away from them at the same time? No - it doesn't matter! No matter how fast they move and no matter how fast we move, their velocity relative to us will always be less than the speed of light.

The final lesson is: They already are elsewhere. Everyone and everything, right now, that isn't at exactly the same place as you are, right now, is in your elsewhere. Nothing can affect you immediately; it cannot affect you for at least the time it takes light to travel from it to you.

Just ask anyone who plays multiplayer "real-time" games online.