Astronomy Picture of the Day
    


The Sloan Great Wall: Largest Known Structure
<< Yesterday 7.11.2007 Tomorrow >>
The Sloan Great Wall: Largest Known Structure
Credit & Copyright: W. Schaap (U. Gorningen) et al., 2dF Galaxy Redshift Survey
Explanation: What is the largest structure known? The answer might depend on how one defines "structure." A grouping of galaxies known as the Sloan Great Wall was discovered in the Sloan Digital Sky Survey and is a leading candidate. The Sloan Great Wall can be seen in this digitally recast contour map of galaxies in the Two Degree Field galaxy survey. Galaxies within one billion light years, a redshift of about 0.1, are depicted. The labeled Sloan Great Wall spans over one billion light years, longer than any structure ever measured. Critics worry that the Sloan Great Wall should not itself be characterized as a coherent structure because it is not currently gravitationally bound together and parts of it might never become gravitationally bound. Regardless, the beauty of the local universe of galaxies is evident in the image where several huge superclusters of galaxies -- clusters of galaxy clusters -- can also be seen. These include the Shapley Supercluster of galaxies, part of the Pisces-Cetus Supercluster, and part of the Horologium-Reticulum Supercluster.

January
February
March
April
May
June
July
August
September
October
November
December
 < November 2007  >
Mo Tu We Th Fr Sa Su



1234
567891011
12131415161718
19202122232425
2627282930

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.

Based on Astronomy Picture Of the Day

Publications with keywords: galaxies - universe
Publications with words: galaxies - universe
See also:
All publications on this topic >>