Also available at http://math.ucr.edu/home/baez/week267.html July 23, 2008 This Week's Finds in Mathematical Physics (Week 267) John Baez After the workshop on categorical...

The following article: http://cmathphil.blogspot.com/2008/07/on-penroses-argument-against-density.html addresses Penrose’s criticism (Penrose, 2004, The Road to Reality)...

All, Something about the Hawking-Ellis presentation of GR has long bothered me. In their presentation -- which i take to be more or less definitive -- the starting point is...

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On repeating Einstein's rotating disk experiment, I find redshift of rim = sqrt(1 - ^2) = sqrt(1 - ^2) = sqrt(1 - integraldr/^2) = sqrt(1 - 2delphi/c]^2) where w = angular...

Hi! Suppose you have the light-source and dual-slit and screen, setup so you get the classic interference pattern on a screen, and you make a new slit in the screen in the...

Hi: I've remember reading somewhere than ELF radio transmission is inefficient because it requires to much power. If that is the case, wouldn't MW radio...

Schrödinger's Universe One of the very best books, that has recently come out, is Dr. Milo Wolff's brand new book: Schrödinger's Universe. I've just now finished reading...

By what, if any, methods other than by means of the Lienard-Wiechert potentials can the electric and magnetic fields of a moving point-like charge be derived? Any references...

I once did a calculation for a NG, sci.military.moderated IIRC, concerning the lethality of the hypothetical weapon given a beam pulse energy comparable to the muzzle...

Hi there, I am looking for any reference (article, textbook, etc.) that explains the transition from classical continuum mechanics to classical point mechanics (i.e....

In response to a fair amount of recent discussion about Foldy-Wouthuysen on sci.physics.foundations, someone suggested that a Wiki article be started on this topic because...

In reading a paper I came across an expression that, while simple, I didn't really understand the interpretation of: out|A|in/out|in Where |in and |out are just two...

Adam is standing at the edge of a large disc rotating clockwise. Eve is suspended upside down on a large disc rotating counterclockwise. The relative velocity of the...

The twin paradox has been analyzed many times, and many answers are given. Dr. Parker has pointed to the multiplicity of the answers as proof of its underlying error. The...

Dear All, After several attempts, I finally succeeded to compare my proposal with the Lambda-CDM model. This essay can be downloaded at http://www.e-kr.org/ . Thank you...

I would like to consult in private with with young talented physicists on a variety of topics. Including, but not limited to: quantum electrodynamics, solid-state physics,...

I have noticed that Einstein stresses in various places that, whereas the speed/velocity of light is constant in SR, it is not in GR. The reason for my current source of...

If I take 3 playing cards and arrange them in front of my eye, so that a very small triangular aperture is created by the cards, and I adjust this aperture so that it is...

If two electrodes are sandwitching two dielectric materials with very different dielectric constants (but the same thickness), say, water and glass. Would the new dielectric...