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seen Jan 10 '12 at 15:28

Jan
1
revised Myths in the history of Physics
added 287 characters in body
Dec
31
accepted Why do those dolphin bubble rings I saw in a video behave the way they do?
Dec
31
comment Myths in the history of Physics
Oops. Try arxiv.org/abs/0806.3414 .
Dec
31
comment Myths in the history of Physics
I take it that the first argument might be experimental. But what about the second argument? Take a spherical mass, e.g. of metal. Deform it into a barbell shape. Would it fall faster or slower upon deformation? Keep on deforming it until one has two spheres connected by a thin wire. How fast does it fall now? Could cutting the thin wire, decrease the velocity by a factor of two? To me, it's a brilliant argument, and one of the first successful thought experiments in physics. I've always liked it.
Dec
31
awarded  Scholar
Dec
31
accepted What is the difference which leads to attraction in e+e- scattering and repulsion in e-e- scattering in QFT
Dec
31
answered Myths in the history of Physics
Dec
30
awarded  Nice Question
Dec
30
answered How long will the Universe's hydrogen reserves last for?
Dec
28
comment Myths in the history of Physics
True. It's all in the LHC Safety Group report at iopscience.iop.org/0954-3899/35/11/115004/pdf/… . In particular section 2 goes to the questions I alluded to.
Dec
27
comment Myths in the history of Physics
Finally, from the Wikipedia article "... However only a small fraction of this energy would be available for an interaction with a proton or neutron on Earth, with most of the energy remaining in the form of kinetic energy of the products of the interaction. The effective energy available for such a collision is the square root of double the product of the particle's energy and the mass energy of the proton, which for this particle gives 7.5×1014 eV, roughly 50 times the collision energy of the Large Hadron Collider.". Given the difference in luminosities, it seems close, possibly too close.
Dec
27
comment Myths in the history of Physics
Also, wasn't there a loophole in the safety argument due to the fact that the UHECRs were traveling hyper-relativistically w.r.t. the Earth, but that the LEP could theoretically (remotely) create one that might be gravitationally captured by the Earth? How was that eventually handled, by the way?
Dec
27
comment Myths in the history of Physics
Ultra High Energy Cosmic Rays, UHECR's, have been detectected up to 3e20 ev, I.e. > 1e7 the energy of the LEP. They are actually quite fascinating, as you might expect. See en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray
Dec
27
answered What's the explanation for the Giant Magnetoresistance effect?
Dec
27
comment What's the explanation for the Giant Magnetoresistance effect?
Maybe the electrodes somehow don't couple well to all the horizontal layers, so the current has a tendency to spread to adjacent layers? At any rate these guys (see ornl.gov/info/ornlreview/v30n3-4/giant.htm ) seem to have a very detailed model. They will know. There is also something about a waveguide effect which might be relevant.
Dec
27
comment Myths in the history of Physics
Ok, will do. Give a day or so, please. Also Moons of Jupiter could simply be an epicycle, perfectly Ok in the Ptolmeic system, no? Sun could still have orbited the earth. Gallileo did have different evidence to be sure, like imperfections on the moon's surface, suggesting that the moon was like the earth, not in a perfect celestial realm, but not overwhelming evidence of the earth's orbital motion like stellar aberration, found only centuries later. We might have agreed with Cardinal Bellarmine on the astronomical evidence submitted at the time. See the video.
Dec
27
answered Why and how is the speed of light in vacuum constant, i.e., independent of reference frame?
Dec
27
comment What is jet quenching and how far can the hydrodynamic analogy go?
Well, maybe not for this paper, but there is phygg.com/phygg
Dec
27
revised Myths in the history of Physics
added 244 characters in body; added 32 characters in body
Dec
27
revised Myths in the history of Physics
added 411 characters in body; added 134 characters in body