Not enough hours in the day? Scientists predict time will stop completely The theory of time running out was devised by researchers from two Spanish universities trying to explain why the universe appeared to be spreading continuously and accelerating. Observations of supernovae, or exploding stars, found the movement of light indicated they were moving faster than those nearer to the centre of the universe. But the scientists claimed the accepted theory of an opposite force to gravity, known as dark energy, was wrong, and said the reality was that the growth of the universe was slowing.
Gerard ’t Hooft, Theoretical Physics as a Challenge by Gerard 't Hooft Note: This web site will soon be removed from its present address. An updated and renewed version is available at: This is a web site for young students - and anyone else - who are (like me) thrilled by the challenges posed by real science, and who are - like me - determined to use their brains to discover new things about the physical world that we are living in. In short, it is for all those who decided to study theoretical physics, in their own time. It so often happens that I receive mail - well-intended but totally useless - by amateur physicists who believe to have solved the world. Richard Feynman videos Videos This page has been recently updated. The Fantastic Mr Feynman - BBC documentary, May 2013 Feynman's 1984 lecture on Tiny Machines (79 minutes)
Usenet Physics FAQ Version Date: February 2018 This list of answers to frequently asked questions in physics was created by Scott Chase in 1992. Its purpose was to provide good answers to questions that had been discussed often in the sci.physics and related Internet news groups. The articles in this FAQ are based on those discussions and on information from good reference sources. They were later maintained and enlarged by Michael Weiss and Philip Gibbs.
Breakthrough in physics may lead to new view of magnetism An artistic representation of a ‘polaron’ – a new quantum state, or a ‘quasiparticle’. The potassium atom in the middle (blue) repels the smaller lithium atoms (yellow). This creates a complex state, which physically can be best described as a quasiparticle (Illustration: Harald Ritsch) Physics Simulations and Artwork Here is a 3D view of a hydrogren atom in the 4f state. The left image was made in C++ using a technique described by Krzysztof Marczak to make it volumetric like a cloud of smoke. The right image was made in Mathematica by adding 2D cross-sectional layers.
Relativistic Baseball What would happen if you tried to hit a baseball pitched at 90% the speed of light? - Ellen McManis Let’s set aside the question of how we got the baseball moving that fast. We'll suppose it's a normal pitch, except in the instant the pitcher releases the ball, it magically accelerates to 0.9c. From that point onward, everything proceeds according to normal physics. - StumbleUpon A Theory on the Deja Vu or Déjà vu Phenomenon During the time while this web-page has been on the Internet, more than three thousand people (up to Nov 2009) have e-mailed to say that they have Déjà Vu experiences. That is interesting, but their descriptions have virtually always described some different phenomenon. If a person has any pre-knowledge of something that is yet to happen, like in a dream, it cannot be Déjà Vu, and is likely to be some type of Precognition.
Quantum physicists show a small amount of randomness can be amplified without limit Once again quantum physics gives us philosophical implications: physicists showed how a small amount of randomness can be amplified without limit. Classical physics is deterministic: for example, we can determine the position and velocity of a particle at any time in the future. Quantum theory, on the other hand, states that there exist processes which are fundamentally random: for instance, the outcomes of measurements of quantum particles seem to be determined entirely by chance. Classical Mechanics Introduction The purpose of mechanics is to describe how objects change their position in space with time: motion. In physics the atomic hypothesis states: All things are made of atoms - little particles that move around in perpetual motion, attracting each other when they are a distance apart, but repelling upon being squeezed into one another. Richard Feynman Mechanics is described by the following major theories: classical mechanics, relativity and quantum mechanics.
Blog: Higgs Hysteria You know that a scientific idea has penetrated popular culture when people start making jokes about it. Like the one about the priest who changed his name to Higgs so he could be better at giving mass. Or some that say a gadget for negating the Higgs field would be a weapon of mass destruction. Most are variants on a Higgs boson walks into a bar … finally. Such jokes celebrated the Fourth of July announcement of a new subatomic particle, detected amid the debris of proton-proton collisions at a powerful atom smasher in Europe known as the Large Hadron Collider.
The Manhattan Project's Fatal "Demon Core" Sixty six years ago today, Louis Slotin saw a flash of blue light in the depths of Los Alamos National Laboratory. Seconds before, all that separated the young scientist from a lethal dose of radiation was a thin screwdriver. The screwdriver supported a reflective covering that encased a sphere of plutonium, and if the reflector fell into place, a nuclear chain reaction would commence. When Slotin's hand slipped, a lethal burst of radiation hit him, and he died nine days later. One year later, the U.S. military detonated this plutonium "demon core" at the Bikini Atoll in the Pacific Ocean. But the legacy of the demon core -- and its victims -- has endured.
By Controlling Individual Atoms, Researchers Watch Chemical Reactions at the Quantum Level What's the Latest Development? By isolating two individual atoms at extremely low temperatures, researchers have observed how chemical reactions function at the quantum level for the first time. Researchers at the University of Cambridge's Cavendish Laboratory were able to measure the chemical interactions between individual, ultracold ytterbium ions and rubidium atoms. While two atoms will naturally repel each other, scientists observed that "when an atom and a positive ion approach slowly, the ion's charge draws part of the atom's electron cloud towards it, leading to an attractive force between them." What's the Big Idea? The Casimir Effect [Physics FAQ] - [Copyright] Calculation by Don Koks, 2002 Original by Philip Gibbs, 1997 The Casimir effect is a small attractive force that acts between two close parallel uncharged conducting plates. It is due to quantum vacuum fluctuations of the electromagnetic field. The effect was predicted by the Dutch physicist Hendrick Casimir in 1948.