Please forgive my ignorance, but: I just read that an electron can move from an inner orbit to an outer orbit by absorbing kinetic energy through collisions. So why...

In article , Ben Rudiak-Gould wrote: John Baez wrote: In short: for a fundamentally analogue physical...

I have an interesting question. Is it is possible using air ionization to position gas to a particular location using radio waves or a laser? Using a laser that positively...

As I understand it we can think of the Schwarzschild geometry surrounding an isolated star as a static perturbation within an expanding flat or near flat space-time. I would...

Hello group, I'm thinning out my physics library in preparation for an upcoming move. Up for sale are two copies of "Monte Carlo Simulation in Statistical Physics" (4th ed)...

I like to find simple examples which give insight into physics, and came up with these, which I thought quite fun and that some of you might like to try them. Place a single...

Hi all, i have a brief question: Someone has some infromation (paper or other) about an estimation of the bonding energy between some hydrocarbon species and stainless...

Hello everyone! The Bohr-Sommerfeld rule allows approximating the spectra of integrable systems in a quite accurate way, at least for high quantum numbers. The most general...

Hi, On a matter related to several other current threads here, can anyone tell me whether there are experiments that show that the time delay between the emission and the...

Hi all, Reference postings: Unidentified object in a cloud chamber I brightened up the video, grayscaled it and posted it in a higher quality format. I think this shows...

Hello ! I've got two questions about inverse scattering transform (nonlinear PDEs). If a certain equation is integrable by IST method then it should be possible to solve...

Hello everyone, I was wondering if anybody could tell me how to get SHEEP (it's a symbolic tensor manipulation program, which runs under MACSYMA). All the links I found (In...

Among Lorentz transformations, ordinary rotations and boosts are fairly easy to understand, but "null rotations", the transformations that preserve null vectors, are a...

I understand that the velocities of light and gravity are the same in GR theory. Doe this mean that the velocities of EM and gravitational waves of the same frequency will...

Also available at http://math.ucr.edu/home/baez/week234.html June 12, 2006 This Week's Finds in Mathematical Physics (Week 234) John Baez Today I'd like to talk about the...

Why does everybody assume that the gravitational field must be quantized in some sense? Why not simply derive a spacetime independent version of the Schrodinger equation, and...

How would the universe be different if there were only one grade of lepton? And how would our daily lives be different if muons had not been discovered?

Hello, s.p.r. I have worked out curves for speed as a function of slope with various headwinds and tailwinds for a "standard" bicycle. I haven't posted them anywhere. I...

Hi all, I filmed a peculiar "ghost" in an aquarium cloud chamber that my 17 yo son built. The movie is http://www.jwmooney.com/cloud1tcmooney.mpg It is 5.4 Mb The first...

As I understand history, before general relativity Einstein tried and failed to find a Lorenz invariant description of gravitational forces that would reduce suitably to...