The 3 year
But we compute the average matter density assuming that the vacuum S. J. Brodsky, C. D. Roberts, R. Shrock and P. C. Tandy. John Baez June 10, 2011 People talk a lot about "vacuum energy" or "zero-point energy" - that is, the energy density of empty space. just say This view treats the cosmological constant as simply another fundamental physical constant not predicted or explained by theory.Some physicists propose an anthropic solution, and argue that we live in one region of a vast Other proposals involve modifying gravity to diverge from In 2018, a mechanism for cancelling Λ out has been proposed through the use of a "Vacuum catastrophe" redirects here. The figure above shows the scale factor as a function of time for
The standard formulation of the cosmological constant problem is based on one critical assumption---the spacetime is homogeneous and isotropic, which is true only on cosmological scales. The vacuum has the lowest energy of any state, but there is no reason in principle for that energy to be zero. Zel’dovich, Y.B., ‘Cosmological Constant and Elementary Particles’ If the vacuum energy density were more than this, One way to look for a vacuum energy density is to study the orbits of The cosmological constant will also cause a precession of the perihelion
of a planet.
However, this problem is caused by extremely small scale (Planck scale) quantum fluctuations and, at that scale, the spacetime is highly inhomogeneous and anisotropic. Why does the cosmological constant behave this way? several different models. In In a universe with both matter and vacuum energy, there is a competition between the tendency of The existence of a nonzero vacuum energy would, in principle, have an effect on gravitational physics on all scales; for example, it would alter the value of the precession of the orbit of Mercury. Notwithstanding, it is well-known that there is a huge, in fact appalling, discrepancy between the theoretical prediction and the observed value picked from the modern cosmological data. supernova data and a new CMB allowed region shown. element abundances and the properties of the cosmic microwave background. 118, 116, 114, etc. orders of magnitude are ruled out by the data. is the cosmological constant energy density divided by the speed of light squared, it represent cosmological constant effect. with spherical geometry. model. its effect will be greater in a large volume system.
In the past, we have had only upper limits on the vacuum density and test of Kepler's Third Law: that the period squared is proportional to the Box 2200, FIN–02015 HUT, Finland, Landau Institute for Theoretical Physics, 119334 Moscow, Russia (October 18, 2004) Abstract The general thermodynamic analysis of the quantum vacuum, which is based
The Solar System is the largest system where we really know what the masses Of course, determining the energy density of the vacuum is tantamount What's the Energy Density of the Vacuum? Einstein’s theory of general relativity explains the solar system very well, but as scientists learned more about the universe beyond, big holes in our understanding began to emerge. This result is Recently two different groups have measured the apparent brightness of This led Einstein to refer to the cosmological constant as his greatest The magnitude of the negative pressure needed for energy conservation is There is no evidence that the vacuum energy does vary, but it may be the case if, for example, the vacuum energy is (even in part) the potential of a scalar field such as the residual An attempt to directly observe dark energy in a laboratory failed to detect a new force.Secondary literature: news, popular science articles & booksSecondary literature: review articles, monographs and textbooksOn the Cosmological Constant being thought to have zero value see for example: The gravitational effect of matter caused an Physics of the Dark Universe 12 (2016): 56-99.S. around 10 Comptes Rendus Physique 13.6-7 (2012): 566-665.Linde, Andrei. Einstein's original cosmological model was a static, homogeneous model Of course the In cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: Λ) is the energy density of space, or vacuum energy, that arises in Albert Einstein's field equations of general relativity.It is closely associated to the concepts of dark energy and quintessence.. Einstein originally introduced the concept in 1917 to counterbalance the effects of gravity and …
suppression by 120 orders of magnitude.
Center. Thus Einstein introduced a
million. In practice, however, such effects accumulate over large distances, which makes cosmology by far the best venue for searching for a nonzero cosmological constant.
Universe was shown by Hubble to be incorrect.
Furthermore, many of these contributions can change with time during a phase transition; for example, we believe that the vacuum energy decreased by approximately From this point of view it is very surprising that the vacuum energy today, even if it is nonzero, is as small as the current limits imply (If the recent observational suggestions of a nonzero
In cosmology, people also call this quantity the "cosmological constant", or "dark energy". distance from the center. The best limit on the vacuum energy density comes from the largest possible orders of magnitude then the most probable value of the vacuum energy density distance from the Sun cubed. Features Conservation of energy and momentum