Knowing the mind of God: Seven theories of everything - physics-math - 04 March 2010 Read full article Continue reading page |1|2 This story has been edited to clarify that it discusses different approaches being taken to develop a theory of everything. The "theory of everything" is one of the most cherished dreams of science. But theologians needn't lose too much sleep just yet. Here's a brief guide to some of the front runners. String theory This is probably the best known theory of everything, and the most heavily studied. What's more, the mathematics of string theory also rely on extra spatial dimensions, which humans could not experience directly. These are radical suggestions, but many theorists find the string approach elegant and have proposed numerous variations on the basic theme that seem to solve assorted cosmological conundrums. First, string theorists have so far struggled to make new predictions that can be tested. Secondly, there are just too many variants of the theory, any one of which could be correct – and little to choose between them. Quantum graphity
Minkowski diagram Minkowski diagram with resting frame (x,t), moving frame (x′,t′), light cone, and hyperbolas marking out time and space with respect to the origin. The Minkowski diagram, also known as a spacetime diagram, was developed in 1908 by Hermann Minkowski and provides an illustration of the properties of space and time in the special theory of relativity. It allows a quantitative understanding of the corresponding phenomena like time dilation and length contraction without mathematical equations. The term Minkowski diagram is used in both a generic and particular sense. Basics[edit] A photon moving right at the origin corresponds to the yellow track of events, a straight line with a slope of 45°. For simplification in Minkowski diagrams, usually only events in a universe of one space dimension and one time dimension are considered. Each point in the diagram represents a certain position in space and time. Path-time diagram in Newtonian physics[edit] Minkowski diagram in special relativity[edit] and
Planck time In physics, the Planck time (P) is the unit of time in the system of natural units known as Planck units. It is the time required for light to travel, in a vacuum, a distance of 1 Planck length.[1] The unit is named after Max Planck, who was the first to propose it. The Planck time is defined as:[2] where: = /2 is the reduced Planck constant (sometimes h is used instead of ħ in the definition[1]) G = gravitational constant c = speed of light in a vacuum s is the SI unit of time, the second. Physical significance[edit] The Planck time is the unique combination of the gravitational constant G, the special-relativistic constant c, and the quantum constant ħ, to produce a constant with units of time. See also[edit] Notes and references[edit]
Twin paradox In physics, the twin paradox is a thought experiment in special relativity involving identical twins, one of whom makes a journey into space in a high-speed rocket and returns home to find that the twin who remained on Earth has aged more. This result appears puzzling because each twin sees the other twin as traveling, and so, according to an incorrect naive application of time dilation, each should paradoxically find the other to have aged more slowly. However, this scenario can be resolved within the standard framework of special relativity: Acceleration is not relative, unlike position and velocity, and one twin is accelerated more than the other. Starting with Paul Langevin in 1911, there have been numerous explanations of this paradox, many based upon there being no contradiction because there is no symmetry—only one twin has undergone acceleration and deceleration, thus differentiating the two cases. History[edit] Max von Laue (1911, 1913) elaborated on Langevin's explanation.
Even a Glass of Water Is a Mystery to Physicists | David Albert With rendition switcher Question: What are some of the great questions in physics today? David Albert: Sure. There's a glass of water on the table beside me. It was noticed about 80 years ago that if one supposes that the fundamental laws of the world are quantum mechanics, if one supposes that the fundamental physical laws of the world are the ones that we get in quantum mechanics textbooks, this story that I just told about how I know there's a glass of water on the table radically falls apart. Now, this is, at the end of the day, a scientific project. So philosophers can be, or people with philosophical training or philosophical sensitivity can be, helpful here in trying to frame very precisely what the problem is, what would count as an adequate solution to the problem, so on and so forth.
Do Frequent Fliers Age More Slowly Is it just me, or is this flight taking forever? [Credit: MarinaAvila, flickr.com] You’re squeezed into a middle seat, two rows from the back of the plane. It’s barely two hours into your cross-country flight, though you’d swear it’s been longer. Does it just seem like the minutes of your trip are crawling by — or does time actually pass more slowly for people who are mid-flight than for people on the ground? Many of us have heard the idea that time doesn’t pass at the same rate for everyone. This familiar — and paradoxical — plotline comes from a particular tenet of relativity theory known as time dilation. Scientists have shown that time dilation doesn’t just happen on near-speed-of-light journeys. So if time dilation occurs under these everyday conditions, is the slowed-down aging experienced by the space-faring twin also experienced — in a much subtler way — by that more familiar airborne traveler, the frequent flier?
The perfect crime tool: Researchers work on ‘event cloak’ | Raw Story By Agence France-PresseMonday, November 15, 2010 22:54 EDT PARIS — Jewelry robbers, magicians, exam cheats and practical jokers everywhere will have an interest in an offbeat idea launched by physicists on Tuesday: to make the passage of time invisible. The scientists have conceived of a “spacetime cloak” which manipulates light and, in essence, conceals whole events from a viewer. The theory is based on censoring the flow of events, which we perceive as a stream of light particles, also called photons, that strike the retina. By exploiting a characteristic of fiber optics, the flow of photons can be slowed, events edited out and stitched back together, say the team from Imperial College London and Salford University, northwestern England. The theory is expounded in a daunting series of equations and diagrams in the Journal of Optics, published by the Institute of Physics. The refractory index is a determinant of the speed with which the light is transported in the cable. Agence France-Presse
Introduction to special relativity Albert Einstein during a lecture in Vienna in 1921 In physics, special relativity is a fundamental theory concerning space and time, developed by Albert Einstein in 1905[1] as a modification of Galilean relativity. (See "History of special relativity" for a detailed account and the contributions of Hendrik Lorentz and Henri Poincaré.) The theory was able to explain some pressing theoretical and experimental issues in the physics of the time involving light and electrodynamics, such as the failure of the 1887 Michelson–Morley experiment, which aimed to measure differences in the relative speed of light due to the Earth's motion through the hypothetical, and now discredited, luminiferous aether. The predictions of special relativity are almost identical to those of Galilean relativity for most everyday phenomena, in which speeds are much lower than the speed of light, but it makes different, non-obvious predictions for objects moving at very high speeds. Pythagoras' theorem
Fermilab Experiment Hints At Existence of Brand-New Elementary Particle Physicists working with a Fermilab neutrino experiment may have found a new elementary particle whose behavior breaks the known laws of physics. If correct, their results poke holes in the accepted Standard Model of particles and forces, and raise some interesting questions for the Large Hadron Collider and Tevatron experiments. The new particle could even explain the existence of dark matter. Working with Fermilab's MiniBooNE experiment — the first part of the larger planned Booster Neutrino Experiment — physicists found evidence for a fourth flavor of neutrino, according to a new paper published in Physical Review Letters. This means there could be another particle we didn't know about, and that it behaves in a way physicists didn't expect. Neutrinos have been mystifying physicists since they were first theorized decades ago. Examining three years' worth of MiniBooNE data, researchers detected more oscillations than would be possible if there were only three flavors.
£2.2bn superlab where scientists are creating a star on Earth By Daily Mail Reporter Updated: 20:10 GMT, 17 November 2010 It may look like any average building but behind closed doors could lie the answer to safe renewable energy of the future. Here at the National Ignition Facility in Livermore California, scientists are aiming to build the world's first sustainable fusion reactor by 'creating a miniature star on Earth'. Following a series of key experiments over the last few weeks, the £2.2 billion project has inched a little closer to its goal of igniting a workable fusion reaction by 2012. Experiment: Scientists hope that their £2.2billion 'miniature star on earth' will become the world's first sustainable fusion reactor by 2012 According to the National Ignition Facility (NIF) team in Livermore, on November 2 they fired up the 192 lasers beams at the centre of the reactor and aimed them at a glass target containing tritium and deuterium gas. For a direct comparison, the temperature at the centre of the sun is 27 million degrees Fahrenheit.
For the First Time, Humans See Quantum Entanglement With the Naked Eye Physicists at the University of Geneva in Switzerland have devised a new kind of quantum experiment using humans as photon detectors, and in doing so have made the quantum phenomenon of entanglement visible to the naked eye for the first time. For those that need a primer, entanglement is that strange quantum phenomenon that links two particles across distances such that any any measurements carried out on one particle immediately changes the properties of the other--even if they are separated by the entire universe. Einstein called it "spooky action at a distance." And indeed it is weird. Nicolas Gisin at U. of Geneva noted that Italian physicists had previously done an interesting thing with entangled photons. Gisin realized that while the naked eye can't see a single photon, it can certainly see thousands. Sort of. What the Swiss team does know is this: when they started, they had two entangled photons. [Nature]
Riddle of 'God particle' could be solved by 2012: CERN (Update) Physicists said on Tuesday they believed that by the end of 2012 they could determine whether a theorised particle called the Higgs boson, which has unleashed a gruelling decades-long hunt, exists or not. "I'm pretty confident that towards the end of 2012 we will have an answer to the Shakespeare question for the Higgs boson -- to be, or not to be?" Rolf-Dieter Heuer, director general of the European Organisation for Nuclear Research (CERN), told a press conference at Britain's Royal Society. CERN has ordered the world's biggest particle collider to step up the quest to explain mass, one of the greatest puzzles in physics. The key to this is believed to be the Higgs, a notional sub-atomic particle named after British physicist Peter Higgs who mooted its existence in 1964. If it is found, one of the last pieces would be set in place in the famous Standard Model, which seeks to bring all the particles and forces in the Universe under a single, unified theory. "It was wrong," she said.