cosmic inflation refers to

© In the standard hot big bang model, without inflation, the cosmological horizon moves out, bringing new regions into view. leia smith | February 6, 2015 ... Cosmic inflation is so widely accepted that it is often taken as established fact. Inflation for Beginners. [125][126] This theory extends general relativity by removing a constraint of the symmetry of the affine connection and regarding its antisymmetric part, the torsion tensor, as a dynamical variable. We will never find a better magnifying glass to peer at the most intricate details of reality. In the terminology of mathematics and physics, a "metric" is a measure of distance that satisfies a specific list of properties, and the term implies that the sense of distance within the universe is itself changing. [28][29][30] For example, molecules in a canister of gas are distributed homogeneously and isotropically because they are in thermal equilibrium: gas throughout the canister has had enough time to interact to dissipate inhomogeneities and anisotropies. Loop quantum gravity assumes a quantized spacetime. All models of eternal inflation produce an infinite, hypothetical multiverse, typically a fractal. But inflation may also refer to dark energy mentioned at the isotonic expansion section above. In 1980, to explain the conditions observed in the universe, astrophysicist Alan Guth proposed cosmic inflation. It appears that special conditions are necessary since inflation occurs in tunneling between two vacua in the string landscape. These parts of the Universe are outside our current cosmological horizon. But Boltzmann taught us that the thermodynamic arrow of time arises from very non-generic ("low entropy") initial conditions. In the approximation that the expansion is exactly exponential, the horizon is static and remains a fixed physical distance away. But Boltzmann taught us that the thermodynamic arrow of time arises from very non-generic ("low entropy") initial conditions. One is the amplitude of the spectrum and the spectral index, which measures the slight deviation from scale invariance predicted by inflation (perfect scale invariance corresponds to the idealized de Sitter universe). Thank you for signing up to Space. Penrose's shocking conclusion, though, was that obtaining a flat universe without inflation is much more likely than with inflation – by a factor of 10 to the googol (10 to the 100) power! [127] This model focuses on the dynamics of the early universe considered as a hot gas of strings. The gravitational lensing effect is the bending of light rays by a massive object. However, for many years it was not clear why or how the universe might be expanding, or what it might signify. Inflation is the extreme accelerated expansion of the Universe. The leading idea is known as cosmic inflation. So it is not seen as problematic that a field responsible for cosmic inflation and the metric expansion of space has not yet been discovered. This was quickly interpreted as meaning galaxies were receding from Earth. In other words, it leads to a hot Big Bang that arises from an inflationary state, not a singularity. See Guth (1997) for a popular description of the workshop, or, This is known as a "red" spectrum, in analogy to, Technically, these conditions are that the, Technically, this is because the inflaton potential is expressed as a Taylor series in φ/, Breakthrough Prize in Fundamental Physics, the solution of the energy density continuity equation for an ultra-relativistic fluid, Learn how and when to remove this template message, "The Medallists: A list of past Dirac Medallists", "Laureates of the Breakthrough Prize in Fundamental Physics in 2012", "NASA Technology Views Birth of the Universe", "Space Ripples Reveal Big Bang's Smoking Gun", Using Tiny Particles To Answer Giant Questions, "Three-year Wilkinson Microwave Anisotropy Probe (WMAP) observations: Implications for cosmology", The Astrophysical Journal Supplement Series, "Our Baby Universe Likely Expanded Rapidly, Study Suggests", Monthly Notices of the Royal Astronomical Society, International Journal of Modern Physics D, "Magnetic monopoles in Unified Gauge Theories", "Phase Transitions and Magnetic Monopole Production in the Very Early Universe", "Cosmological production of superheavy magnetic monopoles", "Einstein's theory of gravitation and its astronomical consequences. On Saturday, October 10th, we'll be doing some maintenance on Quizlet to keep things running smoothly. Created by. If the Universe was only hot enough to form such particles before a period of inflation, they would not be observed in nature, as they would be so rare that it is quite likely that there are none in the observable universe. When linear dimensions are doubled, the energy density in radiation falls by a factor of sixteen (see the solution of the energy density continuity equation for an ultra-relativistic fluid). Read a free issue of How It Works magazine! Paul Steinhardt, one of the original architects of the inflationary model, introduced the first example of eternal inflation in 1983. [8], In 2002 three of the original architects of the theory were recognized for their major contributions; physicists Alan Guth of M.I.T., Andrei Linde of Stanford, and Paul Steinhardt of Princeton shared the prestigious Dirac Prize "for development of the concept of inflation in cosmology". Wentzel Earth and Space Chapter 18 Quiz Flashcards | Quizlet Other models have been advanced that are claimed to explain some or all of the observations addressed by inflation. Therefore, he proposed that the early universe went through an inflationary de Sitter era. Some have claimed that this is a signature of non-Gaussianity and thus contradicts the simplest models of inflation. (Image credit: By Karl Tate, Infographics Artist). There was a problem. There is evidence for a slight deviation from scale invariance. If the probability of different regions is counted by volume, one should expect that inflation will never end or applying boundary conditions that a local observer exists to observe it, that inflation will end as late as possible. [61] These fluctuations were first calculated by Viatcheslav Mukhanov and G. V. Chibisov in analyzing Starobinsky's similar model. Instead, that honor goes to cosmic inflation, and everyone should understand why. He wishes to redefine the term “Big Bang” so that it only refers to what happened after this alleged period of cosmic inflation that supposedly occurred in the universe's first second. Cosmic inflation offers an explanation, in that the universe expanded by such a large amount, over such a small time, so the entire visible universe is in fact a very small portion of the early universe (in causal contact with surrounding points at that time) which was expanded into everything seen today. Graph of the expansion of the observable universe with inflation. The simplest inflation models, those without fine-tuning, predict a tensor to scalar ratio near 0.1. NY 10036. Inflation theory was developed in the late 1970s and early 80s, with notable contributions by several theoretical physicists, including Alexei Starobinsky at Landau Institute for Theoretical Physics, Alan Guth at Cornell University, and Andrei Linde at Lebedev Physical Institute. ", "Inflation Debate: Is the theory at the heart of modern cosmology deeply flawed? The spectral index, ns is one for a scale-invariant Harrison–Zel'dovich spectrum. In 1964, scientists discovered a faint radio hiss coming from the heavens and realized that the hiss wasn’t just noise. When the incredible burst of inflation begins, the uncertainty that rules nature’s tiniest scales is stretched to astronomical proportions, linking the quantum world with the cosmic. [...] For, if the thermalization is actually doing anything [...] then it represents a definite increasing of the entropy. WMAP Bolsters Case for Cosmic Inflation, March 2006, https://en.wikipedia.org/w/index.php?title=Inflation_(cosmology)&oldid=1000175180, Articles with dead external links from December 2018, Articles with permanently dead external links, Wikipedia indefinitely semi-protected pages, Short description is different from Wikidata, Wikipedia articles needing clarification from November 2012, Articles with unsourced statements from May 2014, Wikipedia articles needing clarification from June 2014, Articles needing additional references from November 2016, All articles needing additional references, Creative Commons Attribution-ShareAlike License, This page was last edited on 13 January 2021, at 23:34. Dark energy is broadly similar to inflation and is thought to be causing the expansion of the present-day universe to accelerate. Weisskopf Professor of Physics, predicts that the universe … And if you have a news tip, correction or comment, let us know at: community@space.com. The interpretation of the no-hair theorem is that the Universe (observable and unobservable) expands by an enormous factor during inflation. Hawking and Page later found ambiguous results when they attempted to compute the probability of inflation in the Hartle-Hawking initial state. Their models failed, however, because of the buildup of entropy over several cycles. [5][114]:223–225 However, Albrecht and Lorenzo Sorbo argued that the probability of an inflationary cosmos, consistent with today's observations, emerging by a random fluctuation from some pre-existent state is much higher than that of a non-inflationary cosmos. Cosmic Inflation Theory explains what happened after Big-Bang. The universe was in a hot and nearly uniform state. The theory of cosmic inflation, first proposed in the 1980s by Guth, the V.F. But if inflation lasted long enough to solve the initial conditions problems, collisions between bubbles became exceedingly rare. Based on a huge amount of experimental observation and theoretical work, it is now believed that the reason for the observation is that space itself is expanding, and that it expanded very rapidly within the first fraction of a second after the Big Bang.
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