January 11, 2013
Astronomers Discover Structure 4 Billion Light Years Across – Largest Known In Universe
redOrbit Staff & Wire Reports - Your Universe Online
Astronomers have reportedly discovered the largest known structure in the universe — a formation so massive it would take a vehicle that was moving at light speed roughly four billion light years to cross it, the Royal Astronomical Society (RAS) announced on Thursday.
The structure is a large quasar group (LQG), or a formation that contains the nuclei of galaxies from the earliest days of the universe´s existence. These quasar groups, which undergo astronomically brief (10 to 100 million years long) periods of extreme brightness that make them eminently visible, are known to be 200 Megaparsecs (Mpc) or more across. In comparison, the distance between Andromeda and the Milky Way is only 0.75 Mpc, the researchers said.
“Based on the Cosmological Principle and the modern theory of cosmology, calculations suggest that astrophysicists should not be able to find a structure larger than 370 Mpc,” the society explained. However, the LQG discovered by University of Central Lancashire (UCLan) astronomer Dr. Roger Clowes and his colleagues “is so significant in size it also challenges the Cosmological Principle: the assumption that the universe, when viewed at a sufficiently large scale, looks the same no matter where you are observing it from.”
Their LQG has a typical dimension of 500 Mpc, and its longest dimension is a whopping 1200 Mpc — 1600 times the distance between our galaxy and its closest neighbor, according to the RAS. Dr. Clowes and his colleagues detail their discovery in Friday´s edition of the journal Monthly Notices of the Royal Astronomical Society.
"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,” the UCLan researchers said. “This is hugely exciting — not least because it runs counter to our current understanding of the scale of the universe.”
“Even traveling at the speed of light, it would take 4 billion light years to cross. This is significant not just because of its size but also because it challenges the Cosmological Principle, which has been widely accepted since Einstein,” he added. “Our team has been looking at similar cases which add further weight to this challenge and we will be continuing to investigate these fascinating phenomena.”
In addition to Dr. Clowes, members of the research team include Kathryn Harris, also of UCLan; Srinivasan Raghunathan and Luis E. Campusano of the Universidad de Chile; Ilona K. Sochting of the University of Oxford; and Matthew J. Graham of the California Institute of Technology (Caltech).