Search results
Results from the WOW.Com Content Network
The "cosmological constant" is a constant term that can be added to Einstein field equations of general relativity.If considered as a "source term" in the field equation, it can be viewed as equivalent to the mass of empty space (which conceptually could be either positive or negative), or "vacuum energy".
The measured dark energy density is Ω Λ ≈ 0.690; the observed ordinary (baryonic) matter energy density is Ω b ≈ 0.0482 and the energy density of radiation is negligible. This leaves a missing Ω dm ≈ 0.258 which nonetheless behaves like matter (see technical definition section above) – dark matter.
This argument depends on the vacuum energy density being constant throughout spacetime, as would be expected if dark energy were the cosmological constant. 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 ...
Dark energy does not exist, some scientists have claimed – which could help get rid of one of the universe’s biggest mysteries. ... Clocks would tick faster in empty space than they would in a ...
The physical nature of dark energy is at present unknown," Huterer said. The new findings appear to corroborate the current standard model of cosmology that includes the theory of general relativity.
Dark energy is one of the greatest mysteries in science today. One of the simplest explanations is that it is a “cosmological constant” – a result of the energy of empty space itself – an ...
The most striking aspect is that it requires a different definition of what it means to be a void. Instead of the general notion that a void is a region of space with a low cosmic mean density; a hole in the distribution of galaxies, it defines voids to be regions in which matter is escaping; which corresponds to the dark energy equation of ...
Different theories of dark energy suggest different values of w, with w < − 1 / 3 for cosmic acceleration (this leads to a positive value of ä in the acceleration equation above). The simplest explanation for dark energy is that it is a cosmological constant or vacuum energy; in this case w = −1.