Clubbed To Death: The Origin
FreeThoughtManifesto (Free subscription) | 07/05/2008
By Rob Dougan - Kurayamino Mix The video features a BBC documentary, about space, Big Bang, Atom explosion, Planet formation & asteroides.
Cosmology
+Vote!
+Vote!
Fourth Of July Fireworks Courtesy Of Big Bang Mini [Happy Fourth]
Kotaku (Free subscription) | 07/04/2008
newVideoPlayer("/Bigbangmini_kotaku.flv", 480, 380,""); It's not just a Fourth of July fireworks display, it's a Fourth of July dual-display! The game is Big Bang Mini, a sort of space shooter in...
- add comment
- send to a friend
- Explore : Video Games
+Vote!
Strong lensing in the Einstein-Straus solution. (arXiv:0807.0380v1 [astro-ph] CROSS LISTED)
Arxiv (Free subscription) | 07/04/2008
We analyse strong lensing in the Einstein-Straus solution with positive cosmological constant. For concreteness we compare the theory to the light deflection of the lensed quasar SDSS J1004+4112.
+Vote!
Quantum gravity as a Fermi liquid. (arXiv:0807.0225v1 [hep-th] CROSS LISTED)
Arxiv (Free subscription) | 07/04/2008
We present a reformulation of loop quantum gravity with a cosmological constant and no matter as a Fermi-liquid theory. When the topological sector is deformed and large gauge symmetry is broken, we show that the Chern-Simons state reduces to Jacobson's degenerate sector describing 1+1 dimensional propagating fermions with nonlocal interactions. The Hamiltonian admits a dual description which we realize...
+Vote!
Tidal Disruption Flares from Recoiling Supermassive Black Holes. (arXiv:0807.0223v1 [astro-ph] CROSS LISTED)
Arxiv (Free subscription) | 07/04/2008
Supermassive black holes ejected from galaxy nuclei by gravitational wave recoil will carry a retinue of bound stars, even in the absence of an accretion disk. We discuss the observable signatures related to these stars, with an emphasis on electromagnetic flares from stars that are tidally disrupted by the black hole. We calculate disruption rates for the bound, and the unbound, stars. The rates...
+Vote!
Gravitational Geons in 1+1 Dimensions. (arXiv:0807.0611v1 [gr-qc])
Arxiv (Free subscription) | 07/04/2008
It is well known that general relativity does not admit gravitational geons that are stationary, asymptotically flat, singularity free and topologically trivial. However, it is likely that general relativity will receive corrections at large curvatures and the modified field equations may admit solutions corresponding to this type of geon. If geons are produced in the early universe and survive until...
+Vote!
Implications of the graviton one-loop effective action on the dynamics of the Universe. (arXiv:0807.0447v1 [gr-qc])
Arxiv (Free subscription) | 07/04/2008
We consider the quantum Friedmann equations which include one-loop vacuum fluctuations due to gravitons and scalar field matter in a FLRW background with constant epsilon=-(dH/dt)/H^2. The resulting expression shows a secular growth if epsilon=n/(1+n) or epsilon=(n+1)/n, with n positive integer and epsilon != {0,1}. We argue that the growing terms are physical and cannot be subtracted by local counterterms....
+Vote!
Homogeneous and Isotropic Born-Infeld Cosmologies. (arXiv:0807.0448v1 [gr-qc])
Arxiv (Free subscription) | 07/04/2008
In this paper I examine cosmological models that contain a stochastic background of nonlinear electromagnetic radiation. I show that for Born-Infeld electrodynamics the equation of state parameter, $w=P/\rho$, remains close to 1/3 throughout the evolution of the universe if $E^2=B^2$ in the late universe to a high degree of accuracy. Theories with electromagnetic Lagrangians of the form $L=-{1/4}F^2+\alpha...
+Vote!
What kinds of coordinate can keep the Hawking temperature invariant for the static spherically symmetric black hole?. (arXiv:0807.0477v1 [gr-qc])
Arxiv (Free subscription) | 07/04/2008
By studying the Hawking radiation of the most general static spherically symmetric black hole arising from scalar and Dirac particles tunnelling, we find the Hawking temperature is invariant in the general coordinate representation (\ref{arbitrary1}), which satisfies two conditions: a) its radial coordinate transformation is regular at the event horizon; and b) there is a time-like Killing vector....
+Vote!
Effect of a positive cosmological constant on cosmic strings. (arXiv:0807.0543v1 [gr-qc])
Arxiv (Free subscription) | 07/04/2008
We study cosmic Nielsen-Olesen strings in space-times with a positive cosmological constant. For the free cosmic string in a cylindrically symmetric space-time, we calculate the contribution of the cosmological constant to the angle deficit, and to the bending of null geodesics. For a cosmic string in a Schwarzschild-de Sitter space-time, we use Kruskal patches around the inner and outer horizons...
- add comment
- send to a friend
- Explore : Shipping, Stolt-Nielsen, Transportation
+Vote!
Basic quantum mechanics for three Dirac equations in a curved spacetime. (arXiv:0807.0570v1 [gr-qc])
Arxiv (Free subscription) | 07/04/2008
We consider three versions of the Dirac equation in a curved spacetime: the standard (Dirac-Fock-Weyl or DFW) equation, and two alternative versions, both of which are based on the recently proposed tensor representation of the Dirac field (TRD). These three equations differ in the covariant derivative D_mu. A common tool is the hermitizing matrix A. Having the current conservation for any solution...
+Vote!
Zero-size objects in Riemann-Cartan spacetime. (arXiv:0807.0596v1 [gr-qc])
Arxiv (Free subscription) | 07/04/2008
We use the conservation law of the stress-energy and spin tensors to study the motion of massive zero-size objects in Riemann-Cartan geometry. The resultant world line equations turn out to exhibit a novel spin-curvature coupling. In particular, the spin of the Dirac particle does not couple to the background curvature. This is a consequence of its truly zero size which consistently rules out the...
+Vote!
The other 'Journey to the Center of the Earth
New York Newsday (Free subscription) | 07/03/2008
We might be digging for an analogy here, but compare the Earth to a golf ball (and the Big Bang as tee time!): Both have a dense inner core, a lighter but rigid middle interior, and a relatively wafer-thin surface. Our planet may not be white and dimpled, but it certainly flies through space.
- add comment
- send to a friend
- Explore : Cinema
+Vote!
The fireworks start early with this Big Bang Mini trailer
DS Fanboy (Free subscription) | 07/03/2008
Filed under: Video What better way to celebrate the impending anniversary of the United States' Declaration of Independence than with less than thirty seconds of video footage of an upcoming DS game? That seems to be the idea behind the timely release of this Big Bang Mini trailer. It's a smart move to promote your fireworks-based game on the eve of one of the most colorfully explosive days of the...
- add comment
- send to a friend
- Explore : Video Games
1Vote!
Lithium: The hole in the big bang theory
New Scientist (Free subscription) | 07/03/2008
What really happened in the first few minutes after the big bang? One element could hold the answer, says (full text available to subscribers)
