Universe is Not Expanding After All, Scientists Say New evidence, based on detailed measurements of the size and brightness of hundreds of galaxies, indicates that the Universe is not expanding after all, says a team of astrophysicists led by Eric Lerner from Lawrenceville Plasma Physics. This image shows a star forming region in a nearby galaxy known as the Large Magellanic Cloud. Image credit: ESA / Hubble. In their study, the scientists tested one of the striking predictions of the Big Bang theory – that ordinary geometry does not work at great distances. In the space around us, on Earth, in the Solar System and our Milky Way Galaxy, as similar objects get farther away, they look fainter and smaller. In contrast, the Big Bang theory tells us that in an expanding Universe objects actually should appear fainter but bigger. So in an expanding Universe the most distant galaxies should have hundreds of times dimmer surface brightness than similar nearby galaxies, making them actually undetectable with present-day telescopes. Eric J.
untitled L'ordinateur quantique ThierryLombry Informaticien Depuis l'invention du premier circuit intégré monolithique par Jack Kilby de Texas Instruments en 1958, l'intégration des composants électroniques n'a cessé d'être améliorée au point que nous parvenons aujourd'hui à faire fonctionner des centaines de milliers de composants sur une puce (chip) mesurant à peine 1 cm2, c'est la technologie ULSI (Ultra Large Scale Integration) qui détrône aujourd'hui le VLSI. Le coeur de l'ordinateur : le microprocesseur Mais à cette échelle la difficulté de fabrication devient digne d'une mission impossible. Représentation artistique des fameux bits quantiques ou qubits. © U.Melbourne/Marc Coe.
What is a gauge? | What's new “Gauge theory” is a term which has connotations of being a fearsomely complicated part of mathematics – for instance, playing an important role in quantum field theory, general relativity, geometric PDE, and so forth. But the underlying concept is really quite simple: a gauge is nothing more than a “coordinate system” that varies depending on one’s “location” with respect to some “base space” or “parameter space”, a gauge transform is a change of coordinates applied to each such location, and a gauge theory is a model for some physical or mathematical system to which gauge transforms can be applied (and is typically gauge invariant, in that all physically meaningful quantities are left unchanged (or transform naturally) under gauge transformations). I was asked recently to explain what a gauge theory was, and so I will try to do so in this post. – Coordinate systems – More generally, a coordinate system can be viewed as an isomorphism and “. , or even , if the origin O and basis vectors to .
Astronomers spy most distant Solar System object ever NASA/ESA/G. Bacon/STScI The Kuiper belt lies beyond Neptune. Astronomers have spotted the most distant object ever seen in the Solar System: a frigid world that currently lies 103 times farther from the Sun than Earth does. Scott Sheppard, an astronomer at the Carnegie Institution for Science in Washington DC, reported the object on 10 November at the American Astronomical Society’s Division for Planetary Sciences meeting in National Harbor, Maryland. The object sits beyond the edge of the Kuiper belt (home to Eris and Pluto), and into the inner fringes of the next part of the Solar System, the Oort cloud. But astronomers have not tracked the newfound object for long enough to know its full path, and there is a chance that it will travel much closer to the Sun than its current distance of 103 astronomical units (au; 1 au is approximately 150 million kilometres). Still, the discovery gives a rare glimpse into the fringes of the Solar System.
String Theory and the Scientific Method | Not Even Wrong There’s a new philosophy of science book out, Richard Dawid’s String Theory and the Scientific Method (available online here if your institution is paying Cambridge University Press appropriately or if you have a credit card). It comes with endorsements from string theorists David Gross and John Schwarz, with Schwarz writing: Richard Dawid argues that string theory plays a novel role in the scientific process that has been neglected by philosophers of science. I believe that this book is a valuable contribution to the philosophy of science, which should interest practicing scientists as well as those who are more interested in the methodology of science. Dawid is a particle theorist turned philosopher, and as you might guess from the endorsement, he approaches string theory from an enthusiast’s point of view. This book has been on my mind ever since I left physics and turned to philosophy in the year 2000. In Dawid’s description, string theorists are still partying like it’s 1999:
untitled Einstein for Everyone Einstein for Everyone Nullarbor Press 2007revisions 2008, 2010, 2011, 2012, 2013 Copyright 2007, 2008, 2010, 2011, 2012, 2013 John D. Norton Published by Nullarbor Press, 500 Fifth Avenue, Pittsburgh, Pennsylvania 15260 with offices in Liberty Ave., Pittsburgh, Pennsylvania, 15222 All Rights Reserved John D. An advanced sequel is planned in this series:Einstein for Almost Everyone 2 4 6 8 9 7 5 3 1 ePrinted in the United States of America no trees were harmed web*bookTM This book is a continuing work in progress. January 1, 2015. Preface For over a decade I have taught an introductory, undergraduate class, "Einstein for Everyone," at the University of Pittsburgh to anyone interested enough to walk through door. With each new offering of the course, I had the chance to find out what content worked and which of my ever so clever pedagogical inventions were failures. At the same time, my lecture notes have evolved. This text owes a lot to many. i i i
Potts model The model is named after Renfrey Potts, who described the model near the end of his 1951 Ph.D. thesis. The model was related to the "planar Potts" or "clock model", which was suggested to him by his advisor, Cyril Domb. The four-state planar Potts model is sometimes known as the Ashkin–Teller model, after Julius Ashkin and Edward Teller, who considered an equivalent model in 1943. Physical description where n = 1, ..., q and that the interaction Hamiltonian be given by with the sum running over the nearest neighbor pairs (i, j) over all lattice sites. What is now known as the standard Potts model was suggested by Potts in the course of the solution above, and uses a simpler Hamiltonian, given by: where δ(si, sj) is the Kronecker delta, which equals one whenever si = sj and zero otherwise. The q=2 standard Potts model is equivalent to the Ising model and the 2-state vector Potts model, with Jp = −2Jc. Discussion Measure theoretic description Interaction energy
125 Great Science Videos: From Astronomy to Physics & Psychology Astronomy & Space Travel A Brief, Wondrous Tour of Earth (From Outer Space) - Video - Recorded from August to October, 2011 at the International Space Station, this HD footage offers a brilliant tour of our planet and stunning views of the aurora borealis.A Universe from Nothing - Video - In 53 minutes, theoretical physicist Lawrence Krauss answers some big enchilada questions, including how the universe came from nothing.A Year of the Moon in 2.5 Minutes - Video - The Lunar Reconnaissance Orbiter has been orbiting the moon for over a year. The footage gets compressed into 2 slick minutes.A Day on Earth (as Seen From Space) - Video - Astronaut Don Pettit trained his camera on planet Earth, took a photo once every 15 seconds, and then created a brilliant time-lapse film.Atlantis's Final Landing at Kennedy Space Center - Video - After more than 30 years, the space shuttle era comes to a close. Video runs 30 minutes. Physics Biology & Chemistry Environment, Geology and & Ecology
LIGO - Laser Interferometer Gravitational Wave Observatory Everything We Just Found Out About Pluto, Courtesy of New Horizons - Futurism | Futurism Page 1 of 24612345...102030...»Last »