TERRY%LAJ.SAINET.MFENET@LLL-MFE.ARPA (08/29/85)
Does anyone have a mail preprocessor which can scan my mail file and
remove any messages which contain the keywords "information", "grain",
and "frame" all in the same message?
I have seen a number of messages pleading for definitions, references,
and explanations all of which are ignored or simply full of the same
kind of statements as were originally requested to be clarified.
Please reply to these requests in a more rigorous and logical fashion.
I see no basis for the assumption that the rest mass of an electron is
due entirely to the mass of its electrostatic energy. The following
equation is then given:
m*c^2 = e^2/r
but a previous message by the same author says that electron radius
is ~ e^2/(m*c^2). Where did the approximation come in? It seems to
me that the first equation yields r = e^2/(m*c^2) as an exact equality.
The value for r is then given as ~ 3*10^15 meters. Is this really
correct? I can't do the calculation myself since the author states that
e is proportional to the charge, without giving the constant of pro-
portionality, so I can't come up with a number for his use of e.
However, 3 quadrillion meters is a fur piece; quite a value for a
poor little electron which has been shown by experiment to be indis-
tinguishable from a point particle (outside of wave/particle duality
effects) ...
Terrypmk@prometheus.UUCP (Paul M Koloc) (09/02/85)
TERRY%LAJ.SAINET.MFENET@LLL-MFE.ARPA Terry of Science Applications Incorporated? at LLNL Magnetic Fusion Energy? picks up on inconsistencies: > I see no basis for the assumption that the rest mass of an electron is > due entirely to the mass of its electrostatic energy. The following > equation is then given: > m*c^2 = e^2/r > radius is ~ e^2/(m*c^2). Where did the approximation come in? > . .. e is proportional to the charge, without giving the constant of > proportionality ... . . a number for his use of e. > The value for r is then given as ~ 3*10^15 meters. Is this really correct? > . .. . poor little electron which has been shown by experiment to be > indistinguishable from a point particle. Clearly the electron has energy tied up in electrostatic energy, and to a lesser degree magnetic energy. We only used the approximation m*c^2 ~ e^2/r + ... . to show that an electron has real physical size and is not a "zero extent" or point particle. Certainly, the electric energy doesn't exceed or exactly equal the electrons rest mass (energy). But, assuming that all of the rest mass energy was due to entirely to its electrostatic energy gives us a lower bound for the radius of an "at rest" electron. The numerical value given was INCORRECTLY copied from a previous article and should read ~ 3*10^(-15) meters. "e" is defined as follows: "e^2" = "q^2/(4*pi*8.854*10-12 newton {meters squared}) where "q" is electron charge (equals 1.6 * 10^{-19}coulombs). I know of NO experiment which has the appropriate sensitivity that shows an electron is indistinguishable from a point. There are equations which can reduce the earth's mass as acting from a point to obtain an usable result. That doesn't mean that the earth's radius is an infintesmal. The mathematical treatment in such cases are not complete, and should not be extrapolated beyond the limit of its assumptions. - - NOTE: MAIL PATH MAY DIFFER FROM HEADER - - +-------------------------------------------------------+--------+ | Paul M. Koloc, President: (301) 445-1075 | FUSION | | Prometheus II Ltd., College Park, MD 20740-0222 | this | | ..umcp-cs!seismo!prometheus!pmk.UUCP | decade | +-------------------------------------------------------+--------+
sra@oddjob.UUCP (Scott R. Anderson) (09/02/85)
In article <522@sri-arpa.ARPA> TERRY%LAJ.SAINET.MFENET@LLL-MFE.ARPA writes: > >I see no basis for the assumption that the rest mass of an electron is >due entirely to the mass of its electrostatic energy. If an electron is a classical sphere of charge of radius r, it will have a "self-energy" of approximately e^2/r. This is the energy needed to hold the charge together (by some unknown force). From the relativistic equivalence of mass and energy, this binding energy will appear as a mass, just as the mass of a nucleus is different from the total of the masses of its component protons and neutrons. >The following equation is then given: > > m*c^2 = e^2/r > >but a previous message by the same author says that electron radius >is ~ e^2/(m*c^2). Where did the approximation come in? The approximation comes in because e^2/r is not exactly the self-energy; there is some unmentioned constant factor involved (for a uniform sphere, I believe it is 3/10). However, the above expression gives rise to a useful arrangement of universal constants, e^2/mc^2, which is referred to as the "classical electron radius". >The value for r is then given as ~ 3*10^15 meters. Is this really >correct? 3*10^(-15) m. As mentioned before, the upper limit on the electron's radius is much smaller than this. Scott Anderson ihnp4!oddjob!kaos!sra
pmk@prometheus.UUCP (Paul M Koloc) (09/03/85)
Scott Anderson ihnp4!oddjob!kaos!sra mentions: > "classical electron radius". 3*10^(-15) m. As mentioned before, > the upper limit on the electron's radius is much smaller than this. > the energy needed to hold the charge together (by some unknown force). hmmm mm?? ? I believe Scott mentioned something of order 10^(-18) meters for the electron radius of an electron at rest. Now where do you think Scotty got that number from? My guess is he thinks it's leprechaunic. Scott, would you be so kind as to render an explanation, and please keep it simple? Remember we are talking about an electron at rest; that does constrain its energy and its associated momentum. I think Terry is checking on the experimental data. So it looks like we really can't CHOOSE to ignore an electron's momentum without ignoring its energy (position and time), now can we Scott. Consider the Enterprise under attack by a beam of "point" electrons. "Captain Kirk, sir, if they were point particles why didn't they go through without damage?" "Scotty, your right, it wasn't the points that blew the starboard engine, it was their damn fourier transform." Energy of fields Held together by an "unknown" force! How about the infinite force of logic? It sure works for quarks. You don't really think its made of littler marbles do you? If there's logic about, it's gotta show up sooner or latter. More marbles inside of marbles? ??? - - NOTE: MAIL PATH MAY DIFFER FROM HEADER - - +-------------------------------------------------------+--------+ | Paul M. Koloc, President: (301) 445-1075 | FUSION | | Prometheus II Ltd., College Park, MD 20740-0222 | this | | ..umcp-cs!seismo!prometheus!pmk.UUCP | decade | +-------------------------------------------------------+--------+
sra@oddjob.UUCP (Scott R. Anderson) (09/05/85)
<< Just the facts, Ma'am. >> >I believe Scott mentioned something of order 10^(-18) meters for the >electron radius of an electron at rest. Now where do you think >Scotty got that number from? Not an electron at rest, an electron who's position is known exactly. And this is an upper limit on the electron radius, not necessarily the radius itself. I got that number from reading physics textbooks. Forgive my faulty memory, though (am I getting old already?); the actual scale is 10^(-17) meters. This is still a factor of 100 less than the classical electron radius ~ 10^(-15) meters. This discrepancy is discussed in many physics books; you might, for example, look at Jackson, Classical Electrodynamics, p. 790. One can also go to the literature for the actual experimental results; I have done so, and have posted the reference to net.sources. What's that? Wrong type of source? Oh, in that case, here's one of them: B.L. Beron, et al., Phys. Rev. Lett. 33, 663 (1974). This is an e+e- collision experiment, and on the basis of this and other experimental results, physicists have concluded that electrons are much smaller than predicted by the classical electromagnetic arguments recently discussed. Scott Anderson ihnp4!oddjob!kaos!sra