RE: [asa] LHC, TOE, and the limits of knowledge

From: George Cooper <>
Date: Wed Sep 17 2008 - 12:39:50 EDT

 Hi George,


[George wrote] 1) Here's an amusing, though relativistically simple,
question. (In fact I was asked it during my grad school oral comp.) Since
the source for electrons at an accelerator like SLAC are emitted at random,
& since the target is a few km away down a pipe only a few cm in diameter,
how does any significant fraction of those electrons manage to make it to
the target?


I would assume the huge mag. field controls their vector, but that is too
obvious an answer, so..?


2) A slightly pedantic comment on "increase of mass with velocity": That is
an old-fashioned, though not "wrong," way to speak about relativistic
dynamics. But if it's to be used it's necessary to remember that in such a
formulation the "longitudinal mass" of a particle differes from its
"transverse mass." The former is mG^3 while the latter is mG, where m is
the rest mass and G = 1/(1 - v^2/c^2)^(-1/2). Many popular discussions
incorrectly use the transverse mass when talking about straight line motion.


This is interesting. What is transverse mass? I can envision the
contraction, but does it squash outward from the direction of travel? [Is
the negative exponent correct?]


 3) On Burgy's earlier comment, I'm not sure that it was Clarke who first
suggested multi-stage rockets. I need to dig out Willy Ley's book on the


There seems to be a number of inventors dating as far back as the 14th


I vaguely recall that it was not part of the original Von Braun program, but
came in to solve the Apollo weight dilemma.






----- Original Message -----

From: Don <> Winterstein


Sent: Wednesday, September 17, 2008 4:44 AM

Subject: Re: [asa] LHC, TOE, and the limits of knowledge


As I recall, Larry Johnston also told us that the klystrons in the Stanford
Linear Accelerator are made to operate as if the speed of electrons at
injection is exactly the speed of light. If it were not, the particles
would not be accelerated. "Accelerated" in this case does not mean increase
in speed but in mass. In other words, the electron speed differs from the
speed of light all along the 2-mile traverse by a negligible amount.




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Received on Wed Sep 17 12:40:11 2008

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