Given that you can't get any darker than perfectly black, and perfectly black bodies radiate and absorb heat according to well known laws, isn't it likely that cold dark...

There was some discussion last year about alternative cosmological approaches which could result in effective BBN timespans which are shorter than in the standard model...

Hi all, I was wondering if someone can explain to me whether: 1) Superconductors are attracted to originally unmagnetised ferromagnetic or paramagnetic materials? AIUI...

Dear Friends, Following up some recent discussions here with such luminaries as Dr. Neumaier, Peter, J. Thornburg, X-Phy, P. Helbig, and of course, the irrepressible Igor...

I did this qualitatively. I took 5 test tubes - filled #1, and put less water (temp of about 40F) in each one with the last one having just a few cc's. The "mass" gradient...

Crossposting allows news-reading software to "know" that the same article appears in both places, so (for example) if you (a human reader of both newsgroups) have read...

In the process of exploring path integration I have come across an integral of the form: ${-oo,+oo} F(x) (dx)^.5 (1) Is there any body of literature about how one does...

The one-sided Laplace transform of the Dirac delta(t-a) is (0^- means this is taken to include 0): $(0^-,+oo) delta(x-a) exp dx = exp (1) see, e.g., with some renaming...

Someone whose identity has overflowed my mental nested-quoting stack wrote: ] | The mass of the planets compared to that of the Sun is very small, | whether one subscribes...

Hi , I am surprised there has not been a single post on Horava-Lif****z gravity on this forum. What do people (esp. steve Carlip, Tom Roberts, John Baez, Jonathan Thornburg...

Hi to all, Here's a scenario: Suppose there is a single particle trapped in its ground state within a rectangular well. The width of the well is x in its rest frame,...

A theoretical physics FAQ http://www.mat.univie.ac.at/~neum/physfaq/physics-faq.html This year, I finally found the time to reorganize the ASCII theoretical physics...

A calculation of the mechanical stresses shows that the central part of the beam produces a torque at the central region of the plane due to the spin of the beam, and the...

In the process of calculate the basic Gaussian integral, we take: ${-oo,+oo}dx exp ${-oo,+oo}dy exp (1) using a dummy variable y, and then turn this...

Two questions I would like to find an answer in the literature, even if a footnote 1) Can we build a fiber bundle on S7 with fiber O(1), to produce an object with isometry...

Chalky wrote: ] I will continue to have reservations in this respect until/unless stellar nucleosynthesis is also explained in terms of...

I decided to make a web page on world energy. The idea is to give an overview of global numbers, that are "non political". (ie, the page is not written to prove a...

Consider the path integral: q_T/2|exp|q_-T/2=$Dq exp i (1) where L(q,q-dot) is the Lagrangian density and H is the Hamiltonian operator. Here, we take this path...

This post was suggested by the very interesting and clearly written paper: Wei-Tao Liu,Wei Wu, Ping-Xing Chen, Cheng-Zu Li, and Jian-Min Yuan, "Experimental verification...

Take a little bit of Nothing. ds = 0 Divide the little bit of Nothing into two “complementary” parts (dx and cdt) such that dx^2 + (cdt)^2 = 0 = ds^2