UCLan researchers make discovery that challenges our perception of space - here's what they found

A researcher from the University of Central Lancashire has made a discovery that challenges some of the basic assumptions about cosmology.

UCLan PhD student Alexia Lopez has discovered something she calls The Big Ring on the Sky, which 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.

Here's what the sky looks like in Lancashire's darkest spot

Two years ago, Ms Lopez 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.

Ms Lopez said: “Neither of these two ultra-large structures is easy to explain in our current understanding of the universe. And their ultra-large sizes, distinctive shapes, and cosmological proximity must surely be telling us something important – but what exactly?"

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.

"Extraordinarily fascinating"

Ms Lopez said: “The Cosmological Principle assumes that the part of the universe we can see is viewed as a ‘fair sample’ of what we expect the rest of the universe to be like. We expect matter to be evenly distributed everywhere in space when we view the universe on a large scale, so there should be no noticeable irregularities above a certain size.

“Cosmologists calculate the current theoretical size limit of structures to be 1.2 billion light-years, yet both of these structures are much larger – the Giant Arc is almost three times bigger and the Big Ring’s circumference is comparable to the Giant Arc’s length.

“From current cosmological theories we didn't think structures on this scale were possible. We could expect maybe one exceedingly large structure in all our observable universe. Yet, the Big Ring and the Giant Arc are two huge structures and are even cosmological neighbours, which is extraordinarily fascinating.”

What does it look like?

The Big Ring appears as an almost perfect ring on the sky, but Alexia’s further analysis reveals that it has more of a coil shape, like a cork-screw, that is aligned face-on with Earth. The Giant Arc, which is approximately 1/15th the radius of the observable universe, shows as an enormous, nearly symmetrical, crescent of galaxies in the remote universe. It is twice the size of the striking Sloan Great Wall of galaxies and clusters that is seen in the relatively nearby universe.

How was it found? Ms Lopez, 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).