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Vacuum energy

Vacuum energy
Vacuum energy is an underlying background energy that exists in space throughout the entire Universe. One contribution to the vacuum energy may be from virtual particles which are thought to be particle pairs that blink into existence and then annihilate in a timespan too short to observe. They are expected to do this everywhere, throughout the Universe. The effects of vacuum energy can be experimentally observed in various phenomena such as spontaneous emission, the Casimir effect and the Lamb shift, and are thought to influence the behavior of the Universe on cosmological scales. Origin[edit] Summing over all possible oscillators at all points in space gives an infinite quantity. Vacuum energy can also be thought of in terms of virtual particles (also known as vacuum fluctuations) which are created and destroyed out of the vacuum. Additional contributions to the vacuum energy come from spontaneous symmetry breaking in quantum field theory. Implications[edit] [citation needed] Notes[edit] Related:  Wikipedia

It's confirmed: Matter is merely vacuum fluctuations - physics-math - 20 November 2008 Matter is built on flaky foundations. Physicists have now confirmed that the apparently substantial stuff is actually no more than fluctuations in the quantum vacuum. The researchers simulated the frantic activity that goes on inside protons and neutrons. Each proton (or neutron) is made of three quarks - but the individual masses of these quarks only add up to about 1% of the proton's mass. Theory says it is created by the force that binds quarks together, called the strong nuclear force. But it has taken decades to work out the actual numbers. So physicists have developed a method called lattice QCD, which models smooth space and time as a grid of separate points. Gnarly calculation Until recently, lattice QCD calculations concentrated on the virtual gluons, and ignored another important component of the vacuum: pairs of virtual quarks and antiquarks. Quark-antiquark pairs can pop up and momentarily transform a proton into a different, more exotic particle. Crunch time Higgs field

Top 10 Ways to Destroy Earth | Black Holes & Sun-Earth Collision | Antimatter Detonation & Von Neumann Machines | Doomsday, Earth Apocalypse & End of World Sam Hughes, LiveScience Contributor | January 12, 2012 08:45am ET Credit: ESA Destroying the Earth is harder than you may have been led to believe. You've seen the action movies where the bad guy threatens to destroy the Earth. Fools. The Earth was built to last. So my first piece of advice to you, dear would-be Earth-destroyer: Do not think this will be easy. ( Editor's Note: This presentation was first published by Sam Hughes on his own website.

Renormalization In quantum field theory, the statistical mechanics of fields, and the theory of self-similar geometric structures, renormalization is any of a collection of techniques used to treat infinities arising in calculated quantities. When describing space and time as a continuum, certain statistical and quantum mechanical constructions are ill defined. To define them, the continuum limit has to be taken carefully. Renormalization establishes a relationship between parameters in the theory when the parameters describing large distance scales differ from the parameters describing small distances. Renormalization was first developed in quantum electrodynamics (QED) to make sense of infinite integrals in perturbation theory. Self-interactions in classical physics[edit] Figure 1. The problem of infinities first arose in the classical electrodynamics of point particles in the 19th and early 20th century. . which becomes infinite in the limit as approaches zero. that makes and restoring factors of and where

Theory of everything A theory of everything (ToE) or final theory, ultimate theory, or master theory is a hypothetical single, all-encompassing, coherent theoretical framework of physics that fully explains and links together all physical aspects of the universe.[1]:6 Finding a ToE is one of the major unsolved problems in physics. Over the past few centuries, two theoretical frameworks have been developed that, as a whole, most closely resemble a ToE. The two theories upon which all modern physics rests are general relativity (GR) and quantum field theory (QFT). GR is a theoretical framework that only focuses on the force of gravity for understanding the universe in regions of both large-scale and high-mass: stars, galaxies, clusters of galaxies, etc. On the other hand, QFT is a theoretical framework that only focuses on three non-gravitational forces for understanding the universe in regions of both small scale and low mass: sub-atomic particles, atoms, molecules, etc. Historical antecedents[edit] [edit]

Vacuum catastrophe In cosmology the vacuum catastrophe refers to the disagreement of 107 orders of magnitude between the upper bound upon the vacuum energy density as inferred from data obtained from the Voyager spacecraft of less than 1014 GeV/m3 and the zero-point energy of 10121 GeV/m3 suggested by a naïve application of quantum field theory.[1] This discrepancy has been termed "the worst theoretical prediction in the history of physics."[2] The magnitude of this discrepancy is entirely beyond the descriptive power of any kind of commonplace comparison. The problem was identified at an early stage by Walther Nernst,[4] who raised the question of the consequences of such a huge energy of vacuum on gravitational effects.[5] A recent philosophical and historical assessment is provided by Rugh and Zinkernagel.[6] See also[edit] References[edit]

Quantum field theory in curved spacetime In particle physics, quantum field theory in curved spacetime is an extension of standard, Minkowski-space quantum field theory to curved spacetime. A general prediction of this theory is that particles can be created by time-dependent gravitational fields (multigraviton pair production), or by time-independent gravitational fields that contain horizons. Description[edit] Interesting new phenomena occur; owing to the equivalence principle the quantization procedure locally resembles that of normal coordinates where the affine connection at the origin is set to zero and a nonzero Riemann tensor in general once the proper (covariant) formalism is chosen; however, even in flat spacetime quantum field theory, the number of particles is not well-defined locally. For non-zero cosmological constants, on curved spacetimes quantum fields lose their interpretation as asymptotic particles. Applications[edit] Approximation to quantum gravity[edit] See also[edit] References[edit] Notes[edit] N.D.

Raising the prospects for quantum levitation An eerie quantum force may one day help separate the surfaces in tiny machines for frictionless movement. More than half-a-century ago, the Dutch theoretical physicist Hendrik Casimir calculated that two mirrors placed facing each other in a vacuum would attract. The mysterious force arises from the energy of virtual particles flitting into and out of existence, as described by quantum theory. Now Norio Inui, a scientist from the University of Hyogo in Japan, has predicted that in certain circumstances a reversal in the direction of the so-called Casimir force would be enough to levitate an extremely thin plate. His calculations are published in the American Institute of Physics' (AIP) Journal of Applied Physics. The Casimir force pushes identical plates together, but changes in the geometry and material properties of one of the plates can reverse the direction of the force. As a next step, many key assumptions in the calculations will need to be experimentally tested.

Zero-point energy Zero-point energy, also called quantum vacuum zero-point energy, is the lowest possible energy that a quantum mechanical physical system may have; it is the energy of its ground state. All quantum mechanical systems undergo fluctuations even in their ground state and have an associated zero-point energy, a consequence of their wave-like nature. The uncertainty principle requires every physical system to have a zero-point energy greater than the minimum of its classical potential well. This results in motion even at absolute zero. For example, liquid helium does not freeze under atmospheric pressure at any temperature because of its zero-point energy. History[edit] In 1900, Max Planck derived the formula for the energy of a single energy radiator, e.g., a vibrating atomic unit:[5] where is Planck's constant, is the frequency, k is Boltzmann's constant, and T is the absolute temperature. According to this expression, an atomic system at absolute zero retains an energy of ½hν. Varieties[edit] .

Quantum gravity Quantum gravity (QG) is a field of theoretical physics that seeks to describe the force of gravity according to the principles of quantum mechanics. Although a quantum theory of gravity is needed in order to reconcile general relativity with the principles of quantum mechanics, difficulties arise when one attempts to apply the usual prescriptions of quantum field theory to the force of gravity.[3] From a technical point of view, the problem is that the theory one gets in this way is not renormalizable and therefore cannot be used to make meaningful physical predictions. As a result, theorists have taken up more radical approaches to the problem of quantum gravity, the most popular approaches being string theory and loop quantum gravity.[4] Strictly speaking, the aim of quantum gravity is only to describe the quantum behavior of the gravitational field and should not be confused with the objective of unifying all fundamental interactions into a single mathematical framework.

Future and Cosmos: “Vacuum Catastrophe” Should Be Called the Vacuum Miracle We tend to think of science as something that gives us the right answers. Almost always science does give us the right answer. But there is at least one case when science gives us the wrong answer – a really, really wrong answer. In fact, there is one case in which science gives us an answer wronger than any answer that you ever gave in school, even on those tests when you wrote wild guesses on your exam sheet because you had daydreamed through every class session. The wrong answer given by science is the answer that it gives to the question: how much energy is in a vacuum? A person not familiar with quantum mechanics tends to think of a vacuum as being just empty space. You can get an idea of the modern concept of the vacuum by looking at the animation below. Imagine if there was a weird rule in your living room that every second 10,000 fireflies had to pop into existence, but that each of them would disappear a fraction of a second later. How far off is this calculation?

Zero Point Energy (ZPE) In a recent article in the popular press (The Economist, January 7, 1989, pp. 71-74) it was noted how many of this century's new technologies depend on the Alice-in-Wonderland physics of quantum mechanics, with all of its seeming absurdities. For starters, one begins with the observation that classical physics tells us that atoms, which can be likened to a miniature solar system with electron planets orbiting a nuclear sun, should not exist. The circling electrons should radiate away their energy like microscopic radio antennas and spiral into the nucleus. These are the so-called "logical positivists" who, in a philosophical sense, are like the news reporter whose only interest is the bottom line. However, there are certain conditions in which the uniformity of the background electromagnetic zero-point energy is slightly disturbed and leads to physical effects. What does this have to do with our basic questions? Gravity can thus be understood as a kind of long-range Casimir force. R.

Higgs boson announcement live: Cern scientists discover subatomic particle | Science 7.17am: Good morning all. Two teams of physicists at the Cern laboratory near Geneva are preparing today to announce their latest efforts to discover the Higgs boson. Participants take a rest early before the opening of the seminar. Photograph: Denis Balibouse/AFP/Getty Images The elusive "God particle" has become the most sought-after particle in modern science. Peter Higgs, the Edinburgh University physicist who proposed the idea of the particle in 1964, is flying in to Geneva, as are two other men who published similar theories at around the same time: François Englert, professor emeritus at the Free University of Brussels (ULB) in Belgium, and Tom Kibble, professor emeritus at Imperial College London. There have been rumours, speculation, and, last night, even an apparent leak from the laboratory when a video announcing the discovery of a new particle was accidentally posted on its website. 7.38am: Now, two video links for your viewing pleasure. 8.02am: And we're off. muscleguy:

Daniel Simons Daniel James Simons (born 1969) is a prominent experimental psychologist, cognitive scientist, and Professor in the Department of Psychology and the Beckman Institute for Advanced Science and Technology at the University of Illinois.[1] Simons is most well known for his work on change blindness and inattentional blindness, two surprising examples of how people can be unaware of information right in front of their eyes. His research interests also include visual cognition, perception, memory, attention, and awareness.[2] Biography[edit] Career[edit] Simons received a B.A. in psychology from Carleton College in 1991 and a Ph.D. from Cornell University in 1997. Research[edit] Professor Simons' research has focused on the cognitive underpinnings of our experience of a stable and continuous visual world. Awards[edit] In 2003, Simons won the APA Distinguished Scientific Award for Early Career Contributions to Psychology. References[edit] Books[edit] The Invisible Gorilla (2010) External links[edit]