Huge ring of galaxies discovered
Posted: Mon Jan 15, 2024 7:10 am
UClan student discovers giant ring of galaxies 'so big' it challenges 'understanding of universe'
A Big Cosmological Mystery
A Big Cosmological Mystery
University of Lancaster wrote:
The discovery of a second ultra-large structure in the remote universe has further challenged some of the basic assumptions about cosmology.
The Big Ring on the Sky is 9.2 billion light-years from Earth. It has a diameter of about 1.3 billion light-years, and a circumference of about four billion light-years. If we could step outside and see it directly, the diameter of the Big Ring would need about 15 full Moons to cover it.
It is the second ultra-large structure discovered by University of Central Lancashire (UCLan) PhD student Alexia Lopez who, two years ago, also discovered the Giant Arc on the Sky. Remarkably, the Big Ring and the Giant Arc, which is 3.3 billion light-years across, are in the same cosmological neighbourhood – they are seen at the same distance, at the same cosmic time, and are only 12 degrees apart on the sky.
Such large structures – and there are others found by other cosmologists – challenge our idea of what an ‘average’ region of space looks like. They exceed the size limit of what is considered theoretically viable, and they pose potential challenges to the Cosmological Principle.
AnnAlexia, together with adviser Dr Roger Clowes, both from UCLan’s Jeremiah Horrocks Institute, and collaborator Gerard Williger from the University of Louisville, USA, discovered the new structure by looking at absorption lines in the spectra of quasars from the Sloan Digital Sky Survey (SDSS).
Using the same method that led to the discovery of the Giant Arc, they observed the intervening Magnesium-II (or MgII – it means the atom has lost an electron) absorption systems back-lit by quasars, which are remote super-luminous galaxies. These very-distant, very-bright, quasars act like giant lamps shining a spotlight through distant, but much fainter, intervening galaxies that otherwise would go unseen.