Quantum cosmology In theoretical physics, quantum cosmology is a field attempting to study the effect of quantum mechanics on the formation of the universe, or its early evolution, especially just after the Big Bang. Despite many attempts, such as the Wheeler-deWitt equation, and more recently loop quantum cosmology, the field remains a rather speculative branch of quantum gravity. An important problem in this field is the origin of physical information in the universe. See also[edit] References[edit] External links[edit] Relativity of simultaneity On spaceships, map-clocks may look unsync'ed. Event B is simultaneous with A in the green reference frame, but it occurred before in the blue frame, and will occur later in the red frame. Events A, B, and C occur in different order depending on the motion of the observer. The white line represents a plane of simultaneity being moved from the past to the future. If we imagine one reference frame assigns precisely the same time to two events that are at different points in space, a reference frame that is moving relative to the first will generally assign different times to the two events. A mathematical form of the relativity of simultaneity ("local time") was introduced by Hendrik Lorentz in 1892, and physically interpreted (to first order in v/c) as the result of a synchronization using light signals by Henri Poincaré in 1900. The train-and-platform thought experiment[edit] The train-and-platform experiment from the reference frame of an observer on board the train Spacetime diagrams[edit]
StereoPhoto Maker (French) English , German , Japanese StereoPhoto Maker (SPM) est un éditeur d'images stéréo très souple et performant mais aussi un outil pour visionner les images stéréo. Il permet aussi aux utilisateurs ayant quelques notions de HTML de créer des pages Web utilisant la 'StereoPhotoViewer Applet'. Téléchargement :StereoPhoto Maker Ver5.06 1310 Ko 30/Sep/2014StereoPhoto Maker 64bit Ver5.06 1974 Ko 30/Sep/2014 Ver. 4.43->4.50See here Ver. 4.41->4.43See here English Online Help Great thanks to Pierre MEINDRE for the French-language documentation. Exemples :Exemples d'images stéréo 1Exemples d'images stéréo 2Exemple d'anaglyphe en jaillissement La plupart des modes de visualisation stéréoscopiques sont supportés ainsi qu'un mode monoscopique : Winx3D n'est plus disponible sur le site web original. Alternativement, le logiciel RivaTuner peut être utilisé pour "patcher" une carte nVidia GeForce en "Quadro" rendant ainsi disponibles le mode stéréo OpenGL et les autres fonctionnalités "professionnelles".
4-manifold In mathematics, 4-manifold is a 4-dimensional topological manifold. A smooth 4-manifold is a 4-manifold with a smooth structure. In dimension four, in marked contrast with lower dimensions, topological and smooth manifolds are quite different. There exist some topological 4-manifolds which admit no smooth structure and even if there exists a smooth structure it need not be unique (i.e. there are smooth 4-manifolds which are homeomorphic but not diffeomorphic). 4-manifolds are of importance in physics because, in General Relativity, spacetime is modeled as a pseudo-Riemannian 4-manifold. Topological 4-manifolds[edit] Examples: Freedman's classification can be extended to some cases when the fundamental group is not too complicated; for example, when it is Z there is a classification similar to the one above using Hermitian forms over the group ring of Z. For any finitely presented group it is easy to construct a (smooth) compact 4-manifold with it as its fundamental group. See also[edit]
Vauxhall/Opel to unveil two-seater EV Concept Vauxhall/Opel will reveal an interesting new concept that blends elements of an electric car and a motorbike Image Gallery (3 images) Vauxhall/Opel will reveal an interesting new concept that blends elements of an electric car and a motorbike this week at the Frankfurt Motor Show. The vehicle is still unnamed, but the GM subsidiary describes it as a "production potential" concept that "could revolutionize" urban transport, though just how is left unexplained at the moment. Aimed at the scooter demographic of young drivers and those strapped for cash, the concept is a low-riding electric vehicle with a tandem two-seater arrangement. It has a top speed of 75 mph (120 km/h) and a maximum range on one battery charge of around 60 miles (100 km) at an estimated running cost of one euro per charge. As part of its appeal to younger customers, Vauxhall/Opell hinted at a version limited to 30 mph (45km/h) more suited to the sixteen-year old crowd. About the Author Post a CommentRelated Articles
Invariant mass The invariant mass, rest mass, intrinsic mass, proper mass, or (in the case of bound systems or objects observed in their center of momentum frame) simply mass, is a characteristic of the total energy and momentum of an object or a system of objects that is the same in all frames of reference related by Lorentz transformations. If a center of momentum frame exists for the system, then the invariant mass of a system is simply the total energy divided by the speed of light squared. In other reference frames, the energy of the system increases, but system momentum is subtracted from this, so that the invariant mass remains unchanged. Systems whose four-momentum is a null vector (for example a single photon or many photons moving in exactly the same direction) have zero invariant mass, and are referred to as massless. A physical object or particle moving faster than the speed of light would have space-like four-momenta (such as the hypothesized tachyon), and these do not appear to exist. .
String theory landscape The string theory landscape refers to the huge number of possible false vacua in string theory.[1] The large number of theoretically allowed configurations has prompted suggestions that certain physical mysteries, particularly relating to the fine-tuning of constants like the cosmological constant or the Higgs boson mass, may be explained not by a physical mechanism but by assuming that many different vacua are physically realized.[2] The anthropic landscape thus refers to the collection of those portions of the landscape that are suitable for supporting intelligent life, an application of the anthropic principle that selects a subset of the otherwise possible configurations. Anthropic principle[edit] Bayesian probability[edit] Some physicists, starting with Weinberg, have proposed that Bayesian probability can be used to compute probability distributions for fundamental physical parameters, where the probability of observing some fundamental parameters is given by, where and . Criticism[edit]
Quaternion Graphical representation of quaternion units product as 90°-rotation in 4D-space, ij = k, ji = −k, ij = −ji History[edit] Quaternion plaque on Brougham (Broom) Bridge, Dublin, which says: Here as he walked by on the 16th of October 1843 Sir William Rowan Hamilton in a flash of genius discovered the fundamental formula for quaternion multiplicationi2 = j2 = k2 = ijk = −1 & cut it on a stone of this bridge Quaternion algebra was introduced by Hamilton in 1843.[7] Important precursors to this work included Euler's four-square identity (1748) and Olinde Rodrigues' parameterization of general rotations by four parameters (1840), but neither of these writers treated the four-parameter rotations as an algebra.[8][9] Carl Friedrich Gauss had also discovered quaternions in 1819, but this work was not published until 1900.[10][11] i2 = j2 = k2 = ijk = −1, into the stone of Brougham Bridge as he paused on it. On the following day, Hamilton wrote a letter to his friend and fellow mathematician, John T.
LG15: The Resistance LG15: The Resistance (September 20, 2008—December 12, 2008) was a web television series produced by EQAL that took place within the LG15 Universe. The series was first announced on July 4, 2008 via the official behind-the-scenes LG15 blog, Inside.[1] It premiered on September 16, 2008 at the New York Television Festival,[2] and was first uploaded for public viewing on September 20, 2008.[3] The show continued upon the mythology established by lonelygirl15 and KateModern. LG15: The Resistance also marked the debut of a new LG15.com website. Plot[edit] Season One: "We Will Not Be Stopped"[edit] The first season of the show marks the entrance of the Hymn of None, an organization resisting the Order. The Hymn of None posts a video, exposing a company called LifesBlood Labs to be nothing but a sham to get the blood from Trait Positive girls (like the Order). The Hymn of None posts a puzzle leading Jonas and Sarah to the Samsarine Doctrine. The group travel east. Characters[edit] See also[edit]
Principle of relativity In physics, the principle of relativity is the requirement that the equations describing the laws of physics have the same form in all admissible frames of reference. For example, in the framework of special relativity the Maxwell equations have the same form in all inertial frames of reference. In the framework of general relativity the Maxwell equations or the Einstein field equations have the same form in arbitrary frames of reference. Several principles of relativity have been successfully applied throughout science, whether implicitly (as in Newtonian mechanics) or explicitly (as in Albert Einstein's special relativity and general relativity). History of relativity[edit] Basic relativity principles[edit] Certain principles of relativity have been widely assumed in most scientific disciplines. Any principle of relativity prescribes a symmetry in natural law: that is, the laws must look the same to one observer as they do to another. Special principle of relativity[edit] See also[edit]
Réalité augmentée au British Museum - ARC/blog « le Centre a su se montrer innovant en mobilisant le meilleur des technologies numériques dans le cadre de ses ateliers à destination du jeune pubic. Nous avons d’ores et déjà fait appel aux codes QR, à la capture de mouvement, à l’animation, à la modélisation en 3D, aux interfaces de mouvement avec Kinect et des sites Web mobiles. » Il y a dix-huit mois, l’équipe des programmes d’apprentissage numérique du British Museum a pris un nouveau cap stratégique. Le musée a déjà fait appel à la réalité augmentée, à l’automne 2010, dans le cadre de l’ exposition temporaire « Voyage dans l’au-delà : le Livre des morts de l’Egypte ancienne » (Journey to the Afterlife: The Ancient Egyptian Book of the Dead). Après deux autres coups d’essai à petite échelle, nous avons entrepris un projet plus ambitieux, en partenariat avec quatre lycées londoniens. Ces projets sont représentatifs des programmes d’apprentissage numérique pensés par le Samsung Digital Discovery Centre. Shelley Mannion