En astronomía los vacíos son los espacios entre filamentos, la estructura de mayor escala en el Universo, que contiene muy pocas o ninguna galaxia. Fueron descubiertos por primera vez en 1978 durante un estudio pionero llevado a cabo por Stephen Gregory y Laird A. Thompson en el Observatorio Nacional de Kitt Peak. Los vacíos tienen normalmente un díametro que va desde 11 a 150 Mpc; particularmente, nos referimos a los vacíos grandes, definidos por la ausencia de ricos supercúmulos, como supervacíos. Los vacíos que se encuentran en entornos de alta-densidad son más pequeños que los situados en los espacios de baja-densidad del universo. Se cree que los vacíos se formaron debido a la oscilación acústica de bariones en el Big Bang a causa del colapso de masas seguido de implosiones de materia comprimida de bariones. El exterior de los vacíos es lo que queda de los choques frontales que se ocasionarion debido a este proceso. El desacoplamiento de la materia respecto a la radiación cuando el universo se volvió transparente "congeló" los vacíos y los choques frontales.[cita requerida]

Leer el artículo completo en Wikipedia · CC-BY-SA

Cosmic voids are the vast empty spaces between filaments (the largest-scale structures in the Universe), which contain very few or no galaxies. Voids typically have a diameter of 10 to 100 megaparsecs; particularly large voids, defined by the absence of rich superclusters, are sometimes called supervoids. They have less than one-tenth of the average density of matter abundance that is considered typical for the observable Universe. They were first discovered in 1978 in a pioneering study by Stephen Gregory and Laird A. Thompson at the Kitt Peak National Observatory. Voids are believed to have been formed by baryon acoustic oscillations in the Big Bang, collapses of mass followed by implosions of the compressed baryonic matter. Starting from initially small anisotropies from quantum fluctuations in the early Universe, the anisotropies grew larger in scale over time. Regions of higher density collapsed more rapidly under gravity, eventually resulting in the large-scale, foam-like structure or “cosmic web” of voids and galaxy filaments seen today. Voids located in high-density environments are smaller than voids situated in low-density spaces of the universe. Voids appear to correlate with the observed temperature of the cosmic microwave background (CMB) because of the Sachs–Wolfe effect. Colder regions correlate with voids and hotter regions correlate with filaments because of gravitational redshifting. As the Sachs–Wolfe effect is only significant if the Universe is dominated by radiation or dark energy, the existence of voids is significant in providing physical evidence for dark energy.

Leer el artículo completo en Wikipedia · CC-BY-SA