Κυριακή, 17 Αυγούστου 2008

Η σκοτεινή ύλη λείπει από το κοσμικό κενό

Απόσταση : 1.3 δισεκατομμύρια έτη φωτός
A map of the distribution of galaxies in a thin wedge on the sky, from the Sloan Digital Sky Survey (SDSS-II). The earth is at the vertex of the wedge, and the most distant objects shown are 1.3 billion light years away. Red points mark galaxies whose light is dominated by old stars, while blue points show galaxies with younger populations of stars. Galaxies are arrayed in clumps, filaments, and sheets, which are interweaved with bubbles and tunnels, the cosmic voids. The new study shows that these voids are empty of massive dark matter halos as well as luminous galaxies, and that the numbers and sizes of voids agree with theoretical models in which they grow by gravity starting from a smooth distribution of dark matter in the early universe.
Πηγές στοιχείων : Universe today κι η ιστοσελίδα του Sloan Digital Sky Survey που ήδη αναφέρθηκε.

Δεν υπάρχουν σχόλια: