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]
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. .
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]
Cyrus the Great in the Qur'an Dhul-Qarnayn is thought to refer to Cyrus by some recent Quranic commentators. A "two horned" Elamite figure wrestling with serpents. Cyrus the Great in the Quran is a theory that holds that the character of Dhul-Qarnayn, mentioned in the Quran, is in fact Cyrus the Great. Dhul-Qarnayn (Arabic for "the two-horned") is mentioned in the Quran. Analysis[edit] Abul Ala Maududi, a 20th-century Quran commentator, writes in his Tafsir[3] that the identification of Dhul-Qarnain has been a controversial topic among Islamic scholar from the earliest times. The characteristics of Dhul-Qarnain in the Quran[edit] The characteristics of Dhul-Qarnain in the light of his story as given in the Quran are as follows: (1) The title Dhul-Qarnain ("The Two-Horned") should have been quite familiar to the Jews, for it was at their instigation that the disbelievers of Mecca put this question to Muhammad. According to Maududi's commentary on Surah 18 states: The characteristics of Cyrus the Great[edit] Wall[edit]
Frame of reference Different aspects of "frame of reference"[edit] The need to distinguish between the various meanings of "frame of reference" has led to a variety of terms. For example, sometimes the type of coordinate system is attached as a modifier, as in Cartesian frame of reference. Sometimes the state of motion is emphasized, as in rotating frame of reference. Sometimes the way it transforms to frames considered as related is emphasized as in Galilean frame of reference. Sometimes frames are distinguished by the scale of their observations, as in macroscopic and microscopic frames of reference.[1] In this article, the term observational frame of reference is used when emphasis is upon the state of motion rather than upon the coordinate choice or the character of the observations or observational apparatus. Here is a quotation applicable to moving observational frames and various associated Euclidean three-space coordinate systems [R, R′, etc.]: [4] and this on the utility of separating the notions of
Vinča symbols The Vinča symbols, sometimes called the Vinča signs, Vinča script, Vinča-Turdaș script, Old European script, etc, are a set of symbols found on Neolithic era (6th to 5th millennia BCE) artifacts from the Vinča culture of southeastern Europe. The symbols are mostly considered as constituting the oldest excavated example of "proto-writing" in the world; that is, they probably conveyed a message but did not encode language, predating the development of writing proper by more than a millennium. Discovery[edit] A modern drawing of a clay vessel unearthed in Vinča, found at depth of 8.5 meters. In 1875, archaeological excavations led by the Hungarian archeologist Zsófia Torma (1840–1899) at Tordos (today Turdaș, Romania) unearthed a cache of objects inscribed with previously unknown symbols. The discovery of the Tartaria tablets in Romania by Nicolae Vlassa in 1961 reignited the debate. Fragment of a clay vessel with an "M"-looking incision. Inventory[edit] Meaning of the symbols[edit]
Stress–energy tensor Contravariant components of the stress-energy tensor. Definition[edit] The stress–energy tensor involves the use of superscripted variables (not exponents; see tensor index notation and Einstein summation notation). If Cartesian coordinates in SI units are used, then the components of the position four-vector are given by: x0 = t, x1 = x, x2 = y, and x3 = z, where t is time in seconds, and x, y, and z are distances in meters. In some alternative theories like Einstein–Cartan theory, the stress–energy tensor may not be perfectly symmetric because of a nonzero spin tensor, which geometrically corresponds to a nonzero torsion tensor. Identifying the components of the tensor[edit] Because the stress–energy tensor is of rank two, its components can be displayed in 4 x 4 matrix form: In the following, i and k range from 1 through 3. and for an electromagnetic field in otherwise empty space this component is where E and B are the electric and magnetic fields, respectively.[3] The components where is:
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