Friday, January 18, 2013

Public Weirdness

Black holes are intriguing.  At the event horizon not only can nothing ever escape, but the passage of time, seen from outside, slows to zero because of the intense curvature of space.  Time's arrow shrinks to zero.  Inside the event horizon the curvature of space-time is progressively greater and time's arrow should be reversed.  The further one progresses toward the center the faster time should flow into the past.  Upon reaching the singularity point in the middle of the thing, one should have traveled back in time to the Big Bang.  

But traveling backward in time makes no sense.  Effects would come before things that caused them, things exploding would re-assemble, the old would become young, particles would assemble into the radioactive elements that emitted them, the stink would flow back into the skunk.  Yet that is the logic of time curved more than perpendicularly from our own.  

I have read that the explanation of those impossibilities is that the key phrase is "as seen from outside",  It is the nature of the event horizon that what happens inside cannot be seen from outside.  Which suggests that the event horizon is not just an inconvenience but a logical necessity.  2 plus 2 does not equal 4 because we have carefully measured and found that it is 4 to so many decimal places.  2 plus 2 are exactly 4 because it is a logical necessity and we don't have to measure. Which means that as seen from inside, time would continue to flow normally in one's own immediate frame of reference.

But the problem does not go away so neatly.  The event horizon is only opaque from the outside.  From the inside one should be able to see the outside universe perfectly well because light streams unimpeded into the black hole.  It is as seen from inside the event horizon that all the absurdities would be seen to be happening outside it.   Out here, where you and I are.  Right now.  It is not the inside of the black hole that is impossible and unimaginable, it is right here and now that is. Welcome to the madhouse.

No comments:

Post a Comment