Largest structure in universe discovered, extremely old galaxy cores
Astronomers announced today that they had observed the largest structure yet seen in the universe, an enormous cluster of galaxies from the early Universe that spans an astonishing four billion light-years.
The gargantuan structure is a large quasar group (LQG), in which quasars - the nuclei of ancient galaxies, powered by huge amounts of matter sucked into supermassive black holes and emitting radiation in the process - clump together. Quasars can be observed well, since they are the most luminous, powerful, and energetic objects in the universe and are thus visible well over halfway across the universe - some quasars have a higher energy output than the 100 billion stars of the Milky Way combined.
The discovery of the LQG in the deep Universe, about 8.7 billion light-years away, was made by a team led by Roger Clowes at the Jeremiah Horrocks Institute at Britain's University of Central Lancashire.
For comparison, our galaxy (the Milky Way) is separated from its nearest neighbour, the Andromeda galaxy, by two and a half million light years.
"While it is difficult to fathom the scale of this LQG, we can say quite definitely it is the largest structure ever seen in the entire Universe," Clowes said in a press statement issued by Britain's Royal Astronomical Society (RAS), in whose journal the paper is published.
"This is hugely exciting, not least because it runs counter to our current understanding of the scale of the Universe."
Astronomers have noted since 1982 a tendency for quasars to group together. Huge concentrations of mater such as this are thought to possibly be outgrowths of smaller structures that characterized the universe in its early stage.