# cosmological constant

So how did this concept go from a failed idea to the driving force of universal expansion? cosmological constant, relaxation mechanisms to reduce the cosmological constant to the currently observed value, the geometrical structure of the de Sitter space-time, thermodynamics of the de Sitter universe and the role of string theory in the cosmological constant problem. Ya.B.

a Λ Thus, the gravitational potential of a point mass in a theory with a cosmological constant is (see [6], Chapt. The latter accounted for an unknown force which had the effect of countering or balancing out gravitational attraction and thus stabilizing the universe, avoiding that the solutions to his equations would describe a universe collapsing upon itself. The cosmological constant is denoted by the uppercase Greek letter lambda (Λ) and represents the energy contained by the vacuum of space which would imply that empty space would, unintuitively, possess a density, possibly caused by quantum fluctuations (the temporary, spontaneous, and random appearance of pair of matter-antimatter particles which would immediately annihilate). However, since the advent of Friedmann's evolutionary cosmological model and its experimental verification, the fact that the original Einstein equations have no such solution is not considered a defect of the theory. .mailster-form-1 .mailster-firstname-wrapper input.input{text-align:center;} He added a term which he called the cosmological constant, which puts the Friedmann equation in the form. Why Do “Left” And “Right” Mean Liberal And Conservative? 24). is the Ricci tensor, $R$ Your email address will not be published. Einstein originally posited a nonzero value for the cosmological constant, but after the expansion of the universe was discovered, he lamented that this was his greatest blunder and set the constant to zero [ Davies2007 , pg. 2 “Democracy” vs. “Republic”: Is There A Difference? $$R _ {ij} - { \frac {1} {2} } g _ {ij} R = \ \frac {8 \pi G } {c ^ {4} } T _ {ij} + \Lambda g _ {ij} ,$$. ρ {\displaystyle \Omega _{\Lambda }} Allerdings ist diese statische Lösung instabil, und kleinste Abweichungen von der idealen Materieverteilung lassen das Universum doch wieder je nach Vorzeichen der Störung kollabieren oder expandieren. Auflage. The cosmological constant, often represented by the Greek letter Lambda (λ), was added to Einstein’s field equations to balance the force of gravity. verwendet: Die Annahme, dass die Vakuumenergiedichte auch bei Expansion des Universums konstant bleibt, führt zu der Zustandsgleichung. That supposed mistake turns out to be the cosmological constant, or Λ, which explains the expansion of the universe. $$, where  \Lambda  Cosmological constant, term reluctantly added by Albert Einstein to his equations of general relativity in order to obtain a solution to the equations that described a static universe, as he believed it to be at the time. [1] Sie wirkt (falls sie positiv ist) wie eine der gravitativen Anziehung entgegengesetzte „Expansions-Kraft“. In recent years, as scientists were studying supernovae in an attempt to quantify the expansion of the universe, which was thought to be decelerating, they discovered that it was actually accelerating. This article was most recently revised and updated by, https://www.britannica.com/science/cosmological-constant. 16),$$
Test Your Knowledge - and learn some interesting things along the way. Galaxies within set solid angles were found in greater abundances of redshift (an indication that an object is moving away from us) than expected.

is the gravitational constant. Während in der Physik lange Zeit die Meinung vorherrschte, dass der Wert der kosmologischen Konstante null sei, kommen jüngste Beobachtungen zu einem sehr kleinen, positiven Wert. Dictionary.com Unabridged is the curvature of space, $T _ {ij}$ Abstract Recent cosmological observations suggest the existence of a positive cosmological constant Λ with the magnitude Λ(G~/c3) ≈ 10−123. Learn a new word every day. We have started a video series on Quantum Mechanics on our YouTube channel. This temporary fix to his theory of general relativity would eventually prove to be faulty primarily due to the fact that Einstein solely based his conclusions upon astronomical phenomena occurring in our galaxy. \frac \Lambda {6} Omissions? The existence of a cosmological constant may essentially modify certain steps in the evolution of the most widespread cosmological models (see [2], Chapt. Can you spell these 10 commonly misspelled words? 3 The concept of the cosmological constant as an index of the energy density and pressure of vacuum makes it possible, in principle, to relate the concept of a cosmological constant with the concepts of quantum field theory. Delivered to your inbox! {\displaystyle \Lambda \!\,} This unknown cause of our universe’s acceleration is now more commonly known as dark energy. gravitational constant, and cosmological constant ˙ as scalar fields, and introducing an Einstein-Hilbert action that is considered consistent with the Einstein equations and with the general constraint that is compliant with contracted Bianchi identities and However, this change was merely temporary. The inclusion of…, …by a term, the “cosmological constant,” that Einstein reluctantly introduced into his theory of general relativity in order to counteract the attractive force of gravity and account for a universe that was assumed to be static (neither expanding nor contracting). What is it?

Now, physicists say, the unnaturalness of the Higgs makes the unnaturalness of the, Einstein had invented this idea, called the, In some cases, like with dark energy, Peebles helped show that a, Even those open to the multiverse idea would love to have alternative solutions to the, The elements of string theory that Joe developed are intrinsic to recent attempts to better understand how inflation happened and why the, In seminal work in 2000, Polchinski and a collaborator argued that the plethora of solutions of string theory enables the small value of the, About 20 years ago, astrophysicists discovered that the expansion of the universe is accelerating, driven by an incredibly small source of energy infused in space, known as the, Post the Definition of cosmological constant to Facebook, Share the Definition of cosmological constant on Twitter, 'Cordial': A Word Straight from the Heart. R _ {ij} - { and pressure $p = - c ^ {4} \Lambda / 8 \pi G$, is the metric tensor, $R _ {ij}$ The Cosmological Constant. How Ole Roemer Calculated The Speed Of Light Using A Moon of Jupiter? There are no reliable indications that the cosmological constant is distinct from zero. This review discusses several aspects of the cosmological constant both from the cosmological (sections 1–6) and ﬁeld theoretical (sections 7–11) perspectives.
This website uses cookies to improve your experience. …a factor Λ, the “cosmological constant.” The new term provided a universal cosmic repulsive force, which could act at great distances to counteract the effects of gravity. {\displaystyle G\,} {\displaystyle \rho _{\mathrm {vac} }} p Das wird als Problem der kosmologischen Konstante bezeichnet. Aus einer Reihe verschiedener Beobachtungen wird der Wert der kosmologischen Konstante heute zu

Allerdings kann ein materieerfülltes Universum, dessen Entwicklung durch Gleichungen ohne die Konstante beschrieben wird, nicht statisch sein, sondern muss notwendigerweise expandieren oder kollabieren. Ω { The constant has the effect of a repulsive force that acts against the gravitational attraction of matter in the universe. .mailster-form-1 .mailster-submit-wrapper .submit-button{width:90%;padding-left:5%;padding-right:5%;margin-left:5%;margin-right:5%;text-align:center;}. der dimensionslose Dichteparameter This article aims at discussing the cosmological constant problem at a pedagogical but fully technical level. \int\limits The term $\Lambda g _ {ij}$

+ The European Mathematical Society, A physical constant characterizing the properties of vacuum, sometimes introduced in the general theory of relativity. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica.

Tolman, "Relativity, thermodynamics and cosmology" , Clarendon Press (1934), S. Weinberg, "Gravitation and cosmology" , Wiley (1972). A. Einstein introduced the cosmological constant in the general theory of relativity [1] in order to ensure that the equations of the gravitational field admit a spatially homogeneous static solution (the so-called Einstein cosmological model). WMAP calculated the cosmological constant, finding that another type of energy was necessary to counteract the effects of baryonic matter.

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