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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: awm@google.com . 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).

Rumtidens skjulte dimensioner Rumtidens skjulte dimensioner Rumtiden, som man sædvanligvis tænker på som firedimensional, kan have så mange som syv ekstra dimensioner. Ellevedimensionale strukturer, som studeres nu, kunne give en forenet redegørelse for naturens fire grundlæggende kræfter Daniel Z. Indhold: Indledning Almen relativitet Kaluzas forenede teori Den femte dimension Massive partikler Elektrosvag forening Moderne Kaluza-Klein teorier Supergravitation Teoretiske resultater Superstreng teori Fremtidig udvikling Indledning Den 29. maj, 1919, fejede skyggen fra en total solformørkelse hen over Atlanterhavet fra det vestlige Afrika til det nordlige Brazilien. Observatørerne af formørkelsen ville afprøve en af de forudsagte observationsvirkninger ved Einsteins krumme rumtid. Skønt almen relativitet drejer sig om geometri i kun fire dimensioner, åbnede Einsteins fantasifulde arbejde døren til endnu dristigere anvendelser af hans grundlæggende ide. Hvorfor behøver man 11 dimensioner? Almen relativitet Kaluzas forenede teori

Play framework - Home The Physics of Space Battles 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

Hammer and Feather Corrected Transcript and Commentary Copyright © 1996 by Eric M. Jones. All rights reserved. MP3 Audio Clip ( 6 min 34 sec ) Video Clip 2 min 24 sec ( 0.6 Mb RealVideo or 21 Mb MPG ) 167:02:55 Scott: Whenever you're ready, I'll get the tools off of you (that is, off Jim's PLSS). 167:03:02 Irwin: Okay. 167:03:18 Scott: They want to get that? 167:03:19 Irwin: I guess so; I don't know. 167:03:23 Scott: Yeah. [Jim goes to the back of the Rover, having left the SCB on his seat.] 167:03:25 Allen: Dave, that's affirm. 167:03:33 Scott: Okay. 167:03:35 Irwin: Okay, I'm ready to get the tools off. 167:03:36 Allen: And we're plenty comfortable on the time. 167:03:40 Scott: Yeah, well, we ought to get the descent engine sample first. 167:03:45 Irwin: Okay, well I don't need my bags for that. 167:03:47 Scott: Nope. 167:03:51 Irwin: I'll get the SESC. 167:03:52 Scott: Yeah; and a scoop. 167:03:54 Irwin: Yeah. [Dave goes around the north side of the spacecraft to find a patch of undisturbed soil.

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.

Se Jordens brande de sidste 10 år De sidste 10 år har to af NASA’s satellitter indsamlet data over Jordens brande. Disse billeder har de nu samlet i én stor visuel præsentation af en af naturens mest destruktive fænomener: Ildebrande. Billederne stammer fra instrumentet MODIS (Moderate resolution Imaging Spectroradiometer), som er ombord på NASA’s satellitter ved navn Terra og Aqua. NASA observerer og analyserer brande over hele verden igennem et omfattende researchprogram med satellitter, fly og udstyr på Jorden. »Det man kan se på disse billeder er en rigtig god repræsentation af den satellitdata forskerne bruger til at forstå den globale fordeling af brande og for at fastslå, hvordan brandenes udbredelse stemmer overens med klimaændringer og befolkningens vækst,« siger professor Chris Justice fra University of Maryland, College Park, som er projektleder på MODIS. Forståelse for brandes reaktion på årstidsvariationer Terra og Aqua-satellitterne blev skudt i luften i henholdsvis 1999 og 2002. Fakta

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

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