🚀 go-pugleaf

cannon@scs.unt.edu (Dustin Cannon (Lab 3460)) writes:

>	I have a question.  I was thinking about the problem of the man 
>walking across a bridge, but he first walks half the distance and then can 
>only walk half the remaining distance and so on.  He never gets to the end, 
>right? 

This is the old Zeno Paradox: the conclusion is not true. If his speed of
walking doesn't decrease, he will (of course) reach the end, mathematically
because the summation 1/2 + 1/4 + 1/8 + 1/16 + ...... is finite.

>	I liked this because it also solves a rather disturbing idea one of 
>my professors once said, which was that as two point charges come in contact 
>with each other they have infinte potential energy due to 1/r.  This, he 
>said, was in his mind a proof of God's exsistence.

Who told you this nonsense? Renormalisation calculus in quantum field
theory knows how to deal with these infinities, and a few time ago
John C. Baez posted a message in which he explained that, even without
QM, the mass would be finite: because gravitation also contributes to
the rest mass, and mass also contributes to the gravitation, we get:

m(r)=m_0 + e^2/r - Gm^2(r)/r

Because in the third term on the left-hand side we have m(r) instead
of m_0 , we receive in the limit r->0: m(r)= e/\sqrt{G}. Finite.

I don't understand what this has to do with a god.

Quantum gravity and superstring deal with quantisized length, but we
don't understand both of these theories yet complete.

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