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List of unsolved problems in physics

List of unsolved problems in physics
Some of the major unsolved problems in physics are theoretical, meaning that existing theories seem incapable of explaining a certain observed phenomenon or experimental result. The others are experimental, meaning that there is a difficulty in creating an experiment to test a proposed theory or investigate a phenomenon in greater detail. Unsolved problems by subfield[edit] The following is a list of unsolved problems grouped into broad area of physics.[1] Cosmology, and general relativity[edit] Cosmic inflation Is the theory of cosmic inflation correct, and if so, what are the details of this epoch? Horizon problem Electroweak Horizon Problem Why aren't there obvious large-scale discontinuities in the electroweak vacuum, if distant parts of the observable universe were causally separate when the electroweak epoch ended? Future of the universe Is the universe heading towards a Big Freeze, a Big Rip, a Big Crunch or a Big Bounce? Gravitational wave Can gravitational waves be directly detected? .

Statistical Data Mining Tutorials Advertisment: In 2006 I joined Google. We are growing a Google Pittsburgh office on CMU's campus. We are hiring creative computer scientists who love programming, and Machine Learning is one the focus areas of the office. We're also currently accepting resumes for Fall 2008 intenships. If you might be interested, feel welcome to send me email: . The following links point to a set of tutorials on many aspects of statistical data mining, including the foundations of probability, the foundations of statistical data analysis, and most of the classic machine learning and data mining algorithms. These include classification algorithms such as decision trees, neural nets, Bayesian classifiers, Support Vector Machines and cased-based (aka non-parametric) learning. I hope they're useful (and please let me know if they are, or if you have suggestions or error-corrections).

Ars Electronica Katalogartikel The Noise of the Observer Peter Weibel Modern statistical information theory has its roots in thermodynamics. The relation between information and entropy as "missing information" (L. Boltzmann, 1894) begins with Maxwell's famous demon. "One of the best-established facts in thermodynamics is that it is impossible in a system enclosed in an envelope which permits neither change of volume nor passage of heat, and in which both the temperature and the pressure are everywhere the some, to produce any inequality of temperature or pressure without the expenditure of work. Maxwell offered no definite rejection of his demon. Paul Ehrenfest investigated this question more closely by comparing these intelligent beings with humans, as Smoluchowski had done previously. Yet this concept of energy-use and information proved naive and, in part, incorrect. Precisely at this point another epoch-making paper appeared in the form of Charles H. Entropy is a measure of chance and of disintegration.

Play framework - Home Univers fini de Friedmann Un article de Wikipédia, l'encyclopédie libre. Parmi les nombreux modèles cosmologiques de notre Univers, le modèle d’univers fini de Friedmann occupe une place à part parce qu'il est historiquement l'un des premiers à avoir fourni une image physiquement cohérente du cosmos dans le cadre de la nouvelle théorie de la relativité générale d'Einstein. De plus, sa simplicité intrinsèque et sa richesse font de lui le modèle idéal pour aborder la cosmologie moderne. Cette page est destinée à le présenter en détail. Introduction[modifier | modifier le code] Le modèle d'univers de Friedmann est le plus simple des modèles cosmologiques satisfaisant aux équations d'Einstein. On ne peut toutefois pas aisément visualiser cette situation, car notre espace n'a que trois dimensions alors qu'on traite un objet mathématique abstrait : un espace non réel à quatre dimensions. La métrique FLRW[modifier | modifier le code] On a par ailleurs la métrique euclidienne spatiale : On en déduit la métrique spatiale : .

Amazing Scanning Electron Microscope Photos Amazing Scanning Electron Microscope Photos All these pictures are from the book 'Microcosmos,' created by Brandon Brill from London. This book includes many scanning electron microscope (SEM) images of insects, humanbody parts and household items. These are the most amazing images of what is too small tosee with the naked eye. 2-2-11 An ant, Formica fusca, holding a microchip Surface of an Erasable Programmable Read-Only Memory silicon microchip Eyelash hairs growing from the surface of human skin The surface of a strawberry Bacteria on the surface of a human tongue Human sperm (spermatozoa) Nylon hooks and loops of Velcro Household dust: includes long hairs of cat fur, twisted synthetic and woolen fibers, serrated insect scales, a pollen grain, and plant and insect remains The weave of nylon stocking fibers The head of a mosquito Head louse clinging to a human hair Eight eyes (two groups of four) on the head of a tarantula Cut human hairs and shaving foam between two razor blades Mushrooms spores

Scale Relativity Nottale's work can not be qualified "theory", to the best it is "poetry". He does have ideas, but implements them only with vague analogies. It is unfortunate. In fact, many people have been working before him on this subject, starting with Weyl right after Einstein's original publications. I know it seems paradoxical to reproach a theory with making too many predictions. Besides, Nottale it too busy selling his books and publishing in popular journal to answer the questions raised by the community. I think the whole problem is right here...

Give Ps a chance - Stanford Medicine Magazine - Stanford University School... A Nobelist’s quest to open our eyes to the next DNA. It’s called Poly P By SPYROS ANDREOPOULOS For the past 15 years, Arthur Kornberg, MD, a Nobel Prize-winning biochemist at Stanford, has been deepening his relationship with one of biology’s wallflowers: a molecule he has nicknamed poly P. While most other biochemists ignore the omnipresent molecule (it shows up in every living cell on Earth) Kornberg, 89, can’t pull himself away. “It’s more important than I am,” he says, with a smile. It’s not just his love of a good biochemical mystery that keeps the emeritus professor working in the lab — though that’s certainly part of what drives him. Inorganic polyphosphate, the molecule Kornberg calls poly P, is older than the hills — literally. What exactly is poly P? Kornberg became fascinated by poly P in the 1950s. When Kornberg arrived at Stanford to lead the biochemistry department in the early ’60s, his work on DNA, for which he had received the Nobel Prize in 1959, had heated up.

La relativite d'echelle (ou relativite fractale) Cette théorie est due à Laurent Nottale, physicien au CNRS à l'observatoire de Meudon. On pourra en trouver un exposé dans le numéro 275 de la revue Pour la Science. Cette théorie est une extension directe de la relativité générale. Il se trouve qu'en étendant le principe de relativité, Laurent Nottale a non seulement découvert de nouvelles lois qui se traduisent par des prédictions nouvelles, vérifiées par l'expérience et totalement inexplicables avec d'autres théories, mais encore il a ouvert une voie prometteuse pour l'unification de la relativité et de la mécanique quantique ! Tout ça vous parait trop technique ? Pour plus d'infos : Le site web de Laurent Nottale ATTENTION : La théorie de la relativité d'échelle a récemment (2004, 2005) été sévèrement critiquée, en particulier pour le flou de certain concepts et le nombre d'analogies "poêtiques" qui y figurent, ce qui est, il fautle dire, assez étonnant pour une théorie scientifique. Alors, bidon ou pas bidon ? Intro

Computer learns language by playing games Computers are great at treating words as data: Word-processing programs let you rearrange and format text however you like, and search engines can quickly find a word anywhere on the Web. But what would it mean for a computer to actually understand the meaning of a sentence written in ordinary English — or French, or Urdu, or Mandarin? One test might be whether the computer could analyze and follow a set of instructions for an unfamiliar task. And indeed, in the last few years, researchers at MIT’s Computer Science and Artificial Intelligence Lab have begun designing machine-learning systems that do exactly that, with surprisingly good results. Starting from scratch “Games are used as a test bed for artificial-intelligence techniques simply because of their complexity,” says Branavan, who was first author on both ACL papers. Moreover, Barzilay says, game manuals have “very open text. So initially, its behavior is almost totally random. Proof of concept

Basarab Nicolescu : Le tiers inclus - De la physique quantique à l'ontologie Il s'agit de la communication du physicien théoricien B.Nicolescu, lors du colloque du Centre International de Recherches et d'Études Transdisciplinaires (CIRET), consacré au philosophe Stéphane Lupasco, à Paris. On trouvera l'intégralité du colloque à l'adresse web du CIRET 1. Introduction La philosophie de Lupasco se place sous le double signe de la discontinuité avec la pensée philosophique constituée et de la continuité - cachée, car inhérente à la structure même de la pensée humaine - avec la tradition. On peut déceler trois étapes majeures dans l'oeuvre de Lupasco. Sa thèse de doctorat Du devenir logique et de l'affectivité[1], publiée en 1935, est une méditation approfondie sur le caractère contradictoire de l'espace et du temps, révélé par la théorie de la relativité restreinte d'Einstein. 2. Le fameux état T ("T" du "tiers inclus") fait son apparition à la page 10 du Principe d'antagonisme . 3. 4.